srv0srv.c 65.6 KB
Newer Older
1 2 3 4 5 6 7 8 9
/******************************************************
The database server main program

NOTE: SQL Server 7 uses something which the documentation
calls user mode scheduled threads (UMS threads). One such
thread is usually allocated per processor. Win32
documentation does not know any UMS threads, which suggests
that the concept is internal to SQL Server 7. It may mean that
SQL Server 7 does all the scheduling of threads itself, even
10
in i/o waits. We should maybe modify InnoDB to use the same
11 12 13 14 15 16 17 18 19 20 21 22
technique, because thread switches within NT may be too slow.

SQL Server 7 also mentions fibers, which are cooperatively
scheduled threads. They can boost performance by 5 %,
according to the Delaney and Soukup's book.

Windows 2000 will have something called thread pooling
(see msdn website), which we could possibly use.

Another possibility could be to use some very fast user space
thread library. This might confuse NT though.

unknown's avatar
unknown committed
23
(c) 1995 Innobase Oy
24 25 26

Created 10/8/1995 Heikki Tuuri
*******************************************************/
unknown's avatar
unknown committed
27
/* Dummy comment */
28 29 30 31 32
#include "srv0srv.h"

#include "ut0mem.h"
#include "os0proc.h"
#include "mem0mem.h"
33
#include "mem0pool.h"
34 35 36
#include "sync0sync.h"
#include "thr0loc.h"
#include "que0que.h"
37
#include "srv0que.h"
38 39 40 41 42 43 44 45
#include "log0recv.h"
#include "pars0pars.h"
#include "usr0sess.h"
#include "lock0lock.h"
#include "trx0purge.h"
#include "ibuf0ibuf.h"
#include "buf0flu.h"
#include "btr0sea.h"
46
#include "dict0load.h"
unknown's avatar
Merge  
unknown committed
47
#include "srv0start.h"
unknown's avatar
unknown committed
48
#include "row0mysql.h"
49

unknown's avatar
unknown committed
50 51 52 53
/* This is set to TRUE if the MySQL user has set it in MySQL; currently
affects only FOREIGN KEY definition parsing */
ibool	srv_lower_case_table_names	= FALSE;

54 55 56 57
/* The following counter is incremented whenever there is some user activity
in the server */
ulint	srv_activity_count	= 0;

58 59 60
/* The following is the maximum allowed duration of a lock wait. */
ulint	srv_fatal_semaphore_wait_threshold = 600;

61 62 63 64
/* How much data manipulation language (DML) statements need to be delayed,
in microseconds, in order to reduce the lagging of the purge thread. */
ulint	srv_dml_needed_delay = 0;

unknown's avatar
Merge  
unknown committed
65 66 67
ibool	srv_lock_timeout_and_monitor_active = FALSE;
ibool	srv_error_monitor_active = FALSE;

unknown's avatar
unknown committed
68
const char*	srv_main_thread_op_info = "";
69

70 71 72 73 74 75
/* Server parameters which are read from the initfile */

/* The following three are dir paths which are catenated before file
names, where the file name itself may also contain a path */

char*	srv_data_home 	= NULL;
unknown's avatar
unknown committed
76
#ifdef UNIV_LOG_ARCHIVE
77
char*	srv_arch_dir 	= NULL;
unknown's avatar
unknown committed
78
#endif /* UNIV_LOG_ARCHIVE */
79

unknown's avatar
unknown committed
80 81 82 83
ibool	srv_file_per_table = FALSE;	/* store to its own file each table
					created by an user; data dictionary
					tables are in the system tablespace
					0 */
84 85 86 87
ibool   srv_locks_unsafe_for_binlog = FALSE; /* Place locks to records only 
                                                i.e. do not use next-key locking
                                                except on duplicate key checking and
                                                foreign key checking */
88 89 90 91
ulint	srv_n_data_files = 0;
char**	srv_data_file_names = NULL;
ulint*	srv_data_file_sizes = NULL;	/* size in database pages */ 

unknown's avatar
unknown committed
92 93 94 95 96 97 98
ibool	srv_auto_extend_last_data_file	= FALSE; /* if TRUE, then we
						 auto-extend the last data
						 file */
ulint	srv_last_file_size_max	= 0;		 /* if != 0, this tells
						 the max size auto-extending
						 may increase the last data
						 file size */
99 100 101
ulint	srv_auto_extend_increment = 8;		 /* If the last data file is
						 auto-extended, we add this
						 many pages to it at a time */
102 103
ulint*  srv_data_file_is_raw_partition = NULL;

104 105 106 107 108
/* If the following is TRUE we do not allow inserts etc. This protects
the user from forgetting the 'newraw' keyword to my.cnf */

ibool	srv_created_new_raw	= FALSE;

109 110 111 112 113 114
char**	srv_log_group_home_dirs = NULL; 

ulint	srv_n_log_groups	= ULINT_MAX;
ulint	srv_n_log_files		= ULINT_MAX;
ulint	srv_log_file_size	= ULINT_MAX;	/* size in database pages */ 
ulint	srv_log_buffer_size	= ULINT_MAX;	/* size in database pages */ 
unknown's avatar
unknown committed
115
ulint	srv_flush_log_at_trx_commit = 1;
116

unknown's avatar
unknown committed
117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153
byte	srv_latin1_ordering[256]	/* The sort order table of the latin1
					character set. The following table is
					the MySQL order as of Feb 10th, 2002 */
= {
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07
, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F
, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17
, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F
, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27
, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F
, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37
, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F
, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47
, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F
, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57
, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F
, 0x60, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47
, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F
, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57
, 0x58, 0x59, 0x5A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F
, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87
, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F
, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97
, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F
, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7
, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF
, 0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7
, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF
, 0x41, 0x41, 0x41, 0x41, 0x5C, 0x5B, 0x5C, 0x43
, 0x45, 0x45, 0x45, 0x45, 0x49, 0x49, 0x49, 0x49
, 0x44, 0x4E, 0x4F, 0x4F, 0x4F, 0x4F, 0x5D, 0xD7
, 0xD8, 0x55, 0x55, 0x55, 0x59, 0x59, 0xDE, 0xDF
, 0x41, 0x41, 0x41, 0x41, 0x5C, 0x5B, 0x5C, 0x43
, 0x45, 0x45, 0x45, 0x45, 0x49, 0x49, 0x49, 0x49
, 0x44, 0x4E, 0x4F, 0x4F, 0x4F, 0x4F, 0x5D, 0xF7
, 0xD8, 0x55, 0x55, 0x55, 0x59, 0x59, 0xDE, 0xFF
};
154
		
unknown's avatar
unknown committed
155 156 157 158 159 160 161 162
ulint	srv_pool_size		= ULINT_MAX;	/* size in pages; MySQL inits
						this to size in kilobytes but
						we normalize this to pages in
						srv_boot() */
ulint	srv_awe_window_size 	= 0;		/* size in pages; MySQL inits
						this to bytes, but we
						normalize it to pages in
						srv_boot() */
163 164 165 166 167
ulint	srv_mem_pool_size	= ULINT_MAX;	/* size in bytes */ 
ulint	srv_lock_table_size	= ULINT_MAX;

ulint	srv_n_file_io_threads	= ULINT_MAX;

unknown's avatar
unknown committed
168 169
#ifdef UNIV_LOG_ARCHIVE
ibool	srv_log_archive_on	= FALSE;
170 171
ibool	srv_archive_recovery	= 0;
dulint	srv_archive_recovery_limit_lsn;
unknown's avatar
unknown committed
172
#endif /* UNIV_LOG_ARCHIVE */
173 174

ulint	srv_lock_wait_timeout	= 1024 * 1024 * 1024;
unknown's avatar
unknown committed
175

unknown's avatar
unknown committed
176 177 178
char*   srv_file_flush_method_str = NULL;
ulint   srv_unix_file_flush_method = SRV_UNIX_FDATASYNC;
ulint   srv_win_file_flush_method = SRV_WIN_IO_UNBUFFERED;
179

unknown's avatar
unknown committed
180 181
ulint	srv_max_n_open_files	  = 300;

182 183 184 185 186
/* The InnoDB main thread tries to keep the ratio of modified pages
in the buffer pool to all database pages in the buffer pool smaller than
the following number. But it is not guaranteed that the value stays below
that during a time of heavy update/insert activity. */

187
ulint	srv_max_buf_pool_modified_pct	= 90;
188

189
/* If the following is != 0 we do not allow inserts etc. This protects
unknown's avatar
Merge  
unknown committed
190
the user from forgetting the innodb_force_recovery keyword to my.cnf */
191 192

ulint	srv_force_recovery	= 0;
unknown's avatar
Merge  
unknown committed
193
/*-----------------------*/
194 195 196 197 198 199
/* We are prepared for a situation that we have this many threads waiting for
a semaphore inside InnoDB. innobase_start_or_create_for_mysql() sets the
value. */

ulint   srv_max_n_threads       = 0;

unknown's avatar
Merge  
unknown committed
200 201 202 203 204 205 206
/* The following controls how many threads we let inside InnoDB concurrently:
threads waiting for locks are not counted into the number because otherwise
we could get a deadlock. MySQL creates a thread for each user session, and
semaphore contention and convoy problems can occur withput this restriction.
Value 10 should be good if there are less than 4 processors + 4 disks in the
computer. Bigger computers need bigger values. */

unknown's avatar
unknown committed
207
ulint	srv_thread_concurrency	= 8;
unknown's avatar
Merge  
unknown committed
208 209 210

os_fast_mutex_t	srv_conc_mutex;		/* this mutex protects srv_conc data
					structures */
unknown's avatar
unknown committed
211 212 213 214 215 216 217
lint	srv_conc_n_threads	= 0;	/* number of OS threads currently
					inside InnoDB; it is not an error
					if this drops temporarily below zero
					because we do not demand that every
					thread increments this, but a thread
					waiting for a lock decrements this
					temporarily */
unknown's avatar
unknown committed
218 219 220
ulint	srv_conc_n_waiting_threads = 0;	/* number of OS threads waiting in the
					FIFO for a permission to enter InnoDB
					*/
unknown's avatar
Merge  
unknown committed
221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238

typedef struct srv_conc_slot_struct	srv_conc_slot_t;
struct srv_conc_slot_struct{
	os_event_t			event;		/* event to wait */
	ibool				reserved;	/* TRUE if slot
							reserved */
	ibool				wait_ended;	/* TRUE when another
							thread has already set
							the event and the
							thread in this slot is
							free to proceed; but
							reserved may still be
							TRUE at that point */
	UT_LIST_NODE_T(srv_conc_slot_t)	srv_conc_queue;	/* queue node */
};

UT_LIST_BASE_NODE_T(srv_conc_slot_t)	srv_conc_queue;	/* queue of threads
							waiting to get in */
239
srv_conc_slot_t* srv_conc_slots;			/* array of wait
unknown's avatar
Merge  
unknown committed
240
							slots */
unknown's avatar
unknown committed
241 242 243 244 245

/* Number of times a thread is allowed to enter InnoDB within the same
SQL query after it has once got the ticket at srv_conc_enter_innodb */
#define SRV_FREE_TICKETS_TO_ENTER	500

unknown's avatar
Merge  
unknown committed
246 247 248 249 250
/*-----------------------*/
/* If the following is set TRUE then we do not run purge and insert buffer
merge to completion before shutdown */

ibool	srv_fast_shutdown	= FALSE;
251

252 253 254 255
ibool	srv_very_fast_shutdown	= FALSE; /* if this TRUE, do not flush the
					 buffer pool to data files at the
					 shutdown; we effectively 'crash'
					 InnoDB */
256 257 258
/* Generate a innodb_status.<pid> file */
ibool	srv_innodb_status	= FALSE;

259 260
ibool	srv_use_doublewrite_buf	= TRUE;

unknown's avatar
unknown committed
261 262
ibool   srv_set_thread_priorities = TRUE;
int     srv_query_thread_priority = 0;
unknown's avatar
unknown committed
263 264 265 266 267 268

/* TRUE if the Address Windowing Extensions of Windows are used; then we must
disable adaptive hash indexes */
ibool	srv_use_awe			= FALSE;
ibool	srv_use_adaptive_hash_indexes 	= TRUE;

269 270
/* Maximum allowable purge history length.  <=0 means 'infinite'. */
ulint	srv_max_purge_lag		= 0;
unknown's avatar
unknown committed
271

272 273 274 275 276 277 278 279 280 281 282
/*-------------------------------------------*/
ulint	srv_n_spin_wait_rounds	= 20;
ulint	srv_spin_wait_delay	= 5;
ibool	srv_priority_boost	= TRUE;

ibool	srv_print_thread_releases	= FALSE;
ibool	srv_print_lock_waits		= FALSE;
ibool	srv_print_buf_io		= FALSE;
ibool	srv_print_log_io		= FALSE;
ibool	srv_print_latch_waits		= FALSE;

unknown's avatar
unknown committed
283 284 285 286 287 288 289 290
ulint		srv_n_rows_inserted		= 0;
ulint		srv_n_rows_updated		= 0;
ulint		srv_n_rows_deleted		= 0;
ulint		srv_n_rows_read			= 0;
static ulint	srv_n_rows_inserted_old		= 0;
static ulint	srv_n_rows_updated_old		= 0;
static ulint	srv_n_rows_deleted_old		= 0;
static ulint	srv_n_rows_read_old		= 0;
291

292 293 294 295 296
/*
  Set the following to 0 if you want InnoDB to write messages on
  stderr on startup/shutdown
*/
ibool	srv_print_verbose_log		= TRUE;
297
ibool	srv_print_innodb_monitor	= FALSE;
298 299
ibool   srv_print_innodb_lock_monitor   = FALSE;
ibool   srv_print_innodb_tablespace_monitor = FALSE;
300
ibool   srv_print_innodb_table_monitor = FALSE;
301

302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325
/* The parameters below are obsolete: */

ibool	srv_print_parsed_sql		= FALSE;

ulint	srv_sim_disk_wait_pct		= ULINT_MAX;
ulint	srv_sim_disk_wait_len		= ULINT_MAX;
ibool	srv_sim_disk_wait_by_yield	= FALSE;
ibool	srv_sim_disk_wait_by_wait	= FALSE;

ibool	srv_measure_contention	= FALSE;
ibool	srv_measure_by_spin	= FALSE;
	
ibool	srv_test_extra_mutexes	= FALSE;
ibool	srv_test_nocache	= FALSE;
ibool	srv_test_cache_evict	= FALSE;

ibool	srv_test_sync		= FALSE;
ulint	srv_test_n_threads	= ULINT_MAX;
ulint	srv_test_n_loops	= ULINT_MAX;
ulint	srv_test_n_free_rnds	= ULINT_MAX;
ulint	srv_test_n_reserved_rnds = ULINT_MAX;
ulint	srv_test_array_size	= ULINT_MAX;
ulint	srv_test_n_mutexes	= ULINT_MAX;

326 327 328
/* Array of English strings describing the current state of an
i/o handler thread */

329 330
const char* srv_io_thread_op_info[SRV_MAX_N_IO_THREADS];
const char* srv_io_thread_function[SRV_MAX_N_IO_THREADS];
331

unknown's avatar
unknown committed
332 333
time_t	srv_last_monitor_time;

334 335 336 337 338 339
mutex_t	srv_innodb_monitor_mutex;

/* Mutex for locking srv_monitor_file */
mutex_t	srv_monitor_file_mutex;
/* Temporary file for innodb monitor output */
FILE*	srv_monitor_file;
unknown's avatar
unknown committed
340

unknown's avatar
unknown committed
341 342 343
ulint	srv_main_thread_process_no	= 0;
ulint	srv_main_thread_id		= 0;

344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562
/*
	IMPLEMENTATION OF THE SERVER MAIN PROGRAM
	=========================================

There is the following analogue between this database
server and an operating system kernel:

DB concept			equivalent OS concept
----------			---------------------
transaction		--	process;

query thread		--	thread;

lock			--	semaphore;

transaction set to
the rollback state	--	kill signal delivered to a process;

kernel			--	kernel;

query thread execution:
(a) without kernel mutex
reserved	 	-- 	process executing in user mode;
(b) with kernel mutex reserved
			--	process executing in kernel mode;

The server is controlled by a master thread which runs at
a priority higher than normal, that is, higher than user threads.
It sleeps most of the time, and wakes up, say, every 300 milliseconds,
to check whether there is anything happening in the server which
requires intervention of the master thread. Such situations may be,
for example, when flushing of dirty blocks is needed in the buffer
pool or old version of database rows have to be cleaned away.

The threads which we call user threads serve the queries of
the clients and input from the console of the server.
They run at normal priority. The server may have several
communications endpoints. A dedicated set of user threads waits
at each of these endpoints ready to receive a client request.
Each request is taken by a single user thread, which then starts
processing and, when the result is ready, sends it to the client
and returns to wait at the same endpoint the thread started from.

So, we do not have dedicated communication threads listening at
the endpoints and dealing the jobs to dedicated worker threads.
Our architecture saves one thread swithch per request, compared
to the solution with dedicated communication threads
which amounts to 15 microseconds on 100 MHz Pentium
running NT. If the client
is communicating over a network, this saving is negligible, but
if the client resides in the same machine, maybe in an SMP machine
on a different processor from the server thread, the saving
can be important as the threads can communicate over shared
memory with an overhead of a few microseconds.

We may later implement a dedicated communication thread solution
for those endpoints which communicate over a network.

Our solution with user threads has two problems: for each endpoint
there has to be a number of listening threads. If there are many
communication endpoints, it may be difficult to set the right number
of concurrent threads in the system, as many of the threads
may always be waiting at less busy endpoints. Another problem
is queuing of the messages, as the server internally does not
offer any queue for jobs.

Another group of user threads is intended for splitting the
queries and processing them in parallel. Let us call these
parallel communication threads. These threads are waiting for
parallelized tasks, suspended on event semaphores.

A single user thread waits for input from the console,
like a command to shut the database.

Utility threads are a different group of threads which takes
care of the buffer pool flushing and other, mainly background
operations, in the server.
Some of these utility threads always run at a lower than normal
priority, so that they are always in background. Some of them
may dynamically boost their priority by the pri_adjust function,
even to higher than normal priority, if their task becomes urgent.
The running of utilities is controlled by high- and low-water marks
of urgency. The urgency may be measured by the number of dirty blocks
in the buffer pool, in the case of the flush thread, for example.
When the high-water mark is exceeded, an utility starts running, until
the urgency drops under the low-water mark. Then the utility thread
suspend itself to wait for an event. The master thread is
responsible of signaling this event when the utility thread is
again needed.

For each individual type of utility, some threads always remain
at lower than normal priority. This is because pri_adjust is implemented
so that the threads at normal or higher priority control their
share of running time by calling sleep. Thus, if the load of the
system sudenly drops, these threads cannot necessarily utilize
the system fully. The background priority threads make up for this,
starting to run when the load drops.

When there is no activity in the system, also the master thread
suspends itself to wait for an event making
the server totally silent. The responsibility to signal this
event is on the user thread which again receives a message
from a client.

There is still one complication in our server design. If a
background utility thread obtains a resource (e.g., mutex) needed by a user
thread, and there is also some other user activity in the system,
the user thread may have to wait indefinitely long for the
resource, as the OS does not schedule a background thread if
there is some other runnable user thread. This problem is called
priority inversion in real-time programming.

One solution to the priority inversion problem would be to
keep record of which thread owns which resource and
in the above case boost the priority of the background thread
so that it will be scheduled and it can release the resource.
This solution is called priority inheritance in real-time programming.
A drawback of this solution is that the overhead of acquiring a mutex 
increases slightly, maybe 0.2 microseconds on a 100 MHz Pentium, because
the thread has to call os_thread_get_curr_id.
This may be compared to 0.5 microsecond overhead for a mutex lock-unlock
pair. Note that the thread
cannot store the information in the resource, say mutex, itself,
because competing threads could wipe out the information if it is
stored before acquiring the mutex, and if it stored afterwards,
the information is outdated for the time of one machine instruction,
at least. (To be precise, the information could be stored to
lock_word in mutex if the machine supports atomic swap.)

The above solution with priority inheritance may become actual in the
future, but at the moment we plan to implement a more coarse solution,
which could be called a global priority inheritance. If a thread
has to wait for a long time, say 300 milliseconds, for a resource,
we just guess that it may be waiting for a resource owned by a background
thread, and boost the the priority of all runnable background threads
to the normal level. The background threads then themselves adjust
their fixed priority back to background after releasing all resources
they had (or, at some fixed points in their program code).

What is the performance of the global priority inheritance solution?
We may weigh the length of the wait time 300 milliseconds, during
which the system processes some other thread
to the cost of boosting the priority of each runnable background
thread, rescheduling it, and lowering the priority again.
On 100 MHz Pentium + NT this overhead may be of the order 100
microseconds per thread. So, if the number of runnable background
threads is not very big, say < 100, the cost is tolerable.
Utility threads probably will access resources used by
user threads not very often, so collisions of user threads
to preempted utility threads should not happen very often.

The thread table contains
information of the current status of each thread existing in the system,
and also the event semaphores used in suspending the master thread
and utility and parallel communication threads when they have nothing to do.
The thread table can be seen as an analogue to the process table
in a traditional Unix implementation.

The thread table is also used in the global priority inheritance
scheme. This brings in one additional complication: threads accessing
the thread table must have at least normal fixed priority,
because the priority inheritance solution does not work if a background
thread is preempted while possessing the mutex protecting the thread table.
So, if a thread accesses the thread table, its priority has to be
boosted at least to normal. This priority requirement can be seen similar to
the privileged mode used when processing the kernel calls in traditional
Unix.*/

/* Thread slot in the thread table */
struct srv_slot_struct{
	os_thread_id_t	id;		/* thread id */
	os_thread_t	handle;		/* thread handle */
	ulint		type;		/* thread type: user, utility etc. */
	ibool		in_use;		/* TRUE if this slot is in use */
	ibool		suspended;	/* TRUE if the thread is waiting
					for the event of this slot */
	ib_time_t	suspend_time;	/* time when the thread was
					suspended */
	os_event_t	event;		/* event used in suspending the
					thread when it has nothing to do */
	que_thr_t*	thr;		/* suspended query thread (only
					used for MySQL threads) */
};

/* Table for MySQL threads where they will be suspended to wait for locks */
srv_slot_t*	srv_mysql_table = NULL;

os_event_t	srv_lock_timeout_thread_event;

srv_sys_t*	srv_sys	= NULL;

byte		srv_pad1[64];	/* padding to prevent other memory update
				hotspots from residing on the same memory
				cache line */
mutex_t*	kernel_mutex_temp;/* mutex protecting the server, trx structs,
				query threads, and lock table */
byte		srv_pad2[64];	/* padding to prevent other memory update
				hotspots from residing on the same memory
				cache line */

/* The following three values measure the urgency of the jobs of
buffer, version, and insert threads. They may vary from 0 - 1000.
The server mutex protects all these variables. The low-water values
tell that the server can acquiesce the utility when the value
drops below this low-water mark. */

ulint	srv_meter[SRV_MASTER + 1];
ulint	srv_meter_low_water[SRV_MASTER + 1];
ulint	srv_meter_high_water[SRV_MASTER + 1];
ulint	srv_meter_high_water2[SRV_MASTER + 1];
ulint	srv_meter_foreground[SRV_MASTER + 1];

/* The following values give info about the activity going on in
the database. They are protected by the server mutex. The arrays
are indexed by the type of the thread. */

ulint	srv_n_threads_active[SRV_MASTER + 1];
ulint	srv_n_threads[SRV_MASTER + 1];

563 564 565 566 567 568 569 570 571 572 573 574 575 576
/*************************************************************************
Sets the info describing an i/o thread current state. */

void
srv_set_io_thread_op_info(
/*======================*/
	ulint		i,	/* in: the 'segment' of the i/o thread */
	const char*	str)	/* in: constant char string describing the
				state */
{
	ut_a(i < SRV_MAX_N_IO_THREADS);

	srv_io_thread_op_info[i] = str;
}
577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668

/*************************************************************************
Accessor function to get pointer to n'th slot in the server thread
table. */
static
srv_slot_t*
srv_table_get_nth_slot(
/*===================*/
				/* out: pointer to the slot */
	ulint	index)		/* in: index of the slot */
{
	ut_a(index < OS_THREAD_MAX_N);

	return(srv_sys->threads + index);
}

/*************************************************************************
Gets the number of threads in the system. */

ulint
srv_get_n_threads(void)
/*===================*/
{
	ulint	i;
	ulint	n_threads	= 0;

	mutex_enter(&kernel_mutex);

	for (i = SRV_COM; i < SRV_MASTER + 1; i++) {
	
		n_threads += srv_n_threads[i];
	}

	mutex_exit(&kernel_mutex);

	return(n_threads);
}

/*************************************************************************
Reserves a slot in the thread table for the current thread. Also creates the
thread local storage struct for the current thread. NOTE! The server mutex
has to be reserved by the caller! */
static
ulint
srv_table_reserve_slot(
/*===================*/
			/* out: reserved slot index */
	ulint	type)	/* in: type of the thread: one of SRV_COM, ... */
{
	srv_slot_t*	slot;
	ulint		i;
	
	ut_a(type > 0);
	ut_a(type <= SRV_MASTER);

	i = 0;
	slot = srv_table_get_nth_slot(i);

	while (slot->in_use) {
		i++;
		slot = srv_table_get_nth_slot(i);
	}

	ut_a(slot->in_use == FALSE);
	
	slot->in_use = TRUE;
	slot->suspended = FALSE;
	slot->id = os_thread_get_curr_id();
	slot->handle = os_thread_get_curr();
	slot->type = type;

	thr_local_create();

	thr_local_set_slot_no(os_thread_get_curr_id(), i);

	return(i);
}

/*************************************************************************
Suspends the calling thread to wait for the event in its thread slot.
NOTE! The server mutex has to be reserved by the caller! */
static
os_event_t
srv_suspend_thread(void)
/*====================*/
			/* out: event for the calling thread to wait */
{
	srv_slot_t*	slot;
	os_event_t	event;
	ulint		slot_no;
	ulint		type;

669
#ifdef UNIV_SYNC_DEBUG
670
	ut_ad(mutex_own(&kernel_mutex));
671
#endif /* UNIV_SYNC_DEBUG */
672 673 674 675
	
	slot_no = thr_local_get_slot_no(os_thread_get_curr_id());

	if (srv_print_thread_releases) {
676 677
		fprintf(stderr,
			"Suspending thread %lu to slot %lu meter %lu\n",
unknown's avatar
unknown committed
678 679
			(ulong) os_thread_get_curr_id(), (ulong) slot_no,
			(ulong) srv_meter[SRV_RECOVERY]);
680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721
	}

	slot = srv_table_get_nth_slot(slot_no);

	type = slot->type;

	ut_ad(type >= SRV_WORKER);
	ut_ad(type <= SRV_MASTER);

	event = slot->event;
	
	slot->suspended = TRUE;

	ut_ad(srv_n_threads_active[type] > 0);

	srv_n_threads_active[type]--;

	os_event_reset(event);

	return(event);
}

/*************************************************************************
Releases threads of the type given from suspension in the thread table.
NOTE! The server mutex has to be reserved by the caller! */

ulint
srv_release_threads(
/*================*/
			/* out: number of threads released: this may be
			< n if not enough threads were suspended at the
			moment */
	ulint	type,	/* in: thread type */
	ulint	n)	/* in: number of threads to release */
{
	srv_slot_t*	slot;
	ulint		i;
	ulint		count	= 0;

	ut_ad(type >= SRV_WORKER);
	ut_ad(type <= SRV_MASTER);
	ut_ad(n > 0);
722
#ifdef UNIV_SYNC_DEBUG
723
	ut_ad(mutex_own(&kernel_mutex));
724
#endif /* UNIV_SYNC_DEBUG */
725 726 727 728 729
	
	for (i = 0; i < OS_THREAD_MAX_N; i++) {
	
		slot = srv_table_get_nth_slot(i);

unknown's avatar
unknown committed
730
		if (slot->in_use && slot->type == type && slot->suspended) {
731 732 733 734 735 736 737 738
			
			slot->suspended = FALSE;

			srv_n_threads_active[type]++;

			os_event_set(slot->event);

			if (srv_print_thread_releases) {
739
				fprintf(stderr,
740
		"Releasing thread %lu type %lu from slot %lu meter %lu\n",
741 742
				(ulong) slot->id, (ulong) type, (ulong) i,
		                (ulong) srv_meter[SRV_RECOVERY]);
743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785
			}

			count++;

			if (count == n) {
				break;
			}
		}
	}

	return(count);
}

/*************************************************************************
Returns the calling thread type. */

ulint
srv_get_thread_type(void)
/*=====================*/
			/* out: SRV_COM, ... */
{
	ulint		slot_no;
	srv_slot_t*	slot;
	ulint		type;

	mutex_enter(&kernel_mutex);
	
	slot_no = thr_local_get_slot_no(os_thread_get_curr_id());

	slot = srv_table_get_nth_slot(slot_no);

	type = slot->type;

	ut_ad(type >= SRV_WORKER);
	ut_ad(type <= SRV_MASTER);

	mutex_exit(&kernel_mutex);

	return(type);
}

/*************************************************************************
Initializes the server. */
unknown's avatar
unknown committed
786
static
787 788 789 790
void
srv_init(void)
/*==========*/
{
unknown's avatar
Merge  
unknown committed
791 792 793
	srv_conc_slot_t* 	conc_slot;
	srv_slot_t*		slot;
	ulint			i;
794 795 796 797 798 799

	srv_sys = mem_alloc(sizeof(srv_sys_t));

	kernel_mutex_temp = mem_alloc(sizeof(mutex_t));
	mutex_create(&kernel_mutex);
	mutex_set_level(&kernel_mutex, SYNC_KERNEL);
unknown's avatar
unknown committed
800 801 802

	mutex_create(&srv_innodb_monitor_mutex);
	mutex_set_level(&srv_innodb_monitor_mutex, SYNC_NO_ORDER_CHECK);
803 804 805 806 807 808
	
	srv_sys->threads = mem_alloc(OS_THREAD_MAX_N * sizeof(srv_slot_t));

	for (i = 0; i < OS_THREAD_MAX_N; i++) {
		slot = srv_table_get_nth_slot(i);
		slot->in_use = FALSE;
unknown's avatar
unknown committed
809
                slot->type=0;	/* Avoid purify errors */
810 811 812 813 814 815 816 817 818
		slot->event = os_event_create(NULL);
		ut_a(slot->event);
	}

	srv_mysql_table = mem_alloc(OS_THREAD_MAX_N * sizeof(srv_slot_t));

	for (i = 0; i < OS_THREAD_MAX_N; i++) {
		slot = srv_mysql_table + i;
		slot->in_use = FALSE;
unknown's avatar
unknown committed
819
		slot->type = 0;
820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840
		slot->event = os_event_create(NULL);
		ut_a(slot->event);
	}

	srv_lock_timeout_thread_event = os_event_create(NULL);
	
	for (i = 0; i < SRV_MASTER + 1; i++) {
		srv_n_threads_active[i] = 0;
		srv_n_threads[i] = 0;
		srv_meter[i] = 30;
		srv_meter_low_water[i] = 50;
		srv_meter_high_water[i] = 100;
		srv_meter_high_water2[i] = 200;
		srv_meter_foreground[i] = 250;
	}
	
	srv_sys->operational = os_event_create(NULL);

	ut_a(srv_sys->operational);

	UT_LIST_INIT(srv_sys->tasks);
unknown's avatar
Merge  
unknown committed
841 842 843 844 845 846

	/* Init the server concurrency restriction data structures */

	os_fast_mutex_init(&srv_conc_mutex);
	
	UT_LIST_INIT(srv_conc_queue);
847

848 849
	srv_conc_slots = mem_alloc(OS_THREAD_MAX_N * sizeof(srv_conc_slot_t));

unknown's avatar
Merge  
unknown committed
850 851 852 853 854 855
	for (i = 0; i < OS_THREAD_MAX_N; i++) {
		conc_slot = srv_conc_slots + i;
		conc_slot->reserved = FALSE;
		conc_slot->event = os_event_create(NULL);
		ut_a(conc_slot->event);
	}
856
}	
unknown's avatar
unknown committed
857

858
/*************************************************************************
unknown's avatar
unknown committed
859
Frees the OS fast mutex created in srv_init(). */
unknown's avatar
unknown committed
860

861
void
unknown's avatar
unknown committed
862 863
srv_free(void)
/*==========*/
864
{
unknown's avatar
unknown committed
865
	os_fast_mutex_free(&srv_conc_mutex);
866 867
}

unknown's avatar
unknown committed
868
/*************************************************************************
unknown's avatar
unknown committed
869
Initializes the synchronization primitives, memory system, and the thread
unknown's avatar
unknown committed
870 871 872
local storage. */

void
unknown's avatar
unknown committed
873
srv_general_init(void)
unknown's avatar
unknown committed
874 875
/*==================*/
{
unknown's avatar
unknown committed
876 877 878 879
	os_sync_init();
	sync_init();
	mem_init(srv_mem_pool_size);
	thr_local_init();
unknown's avatar
unknown committed
880 881
}

unknown's avatar
unknown committed
882 883
/*======================= InnoDB Server FIFO queue =======================*/

unknown's avatar
unknown committed
884

unknown's avatar
Merge  
unknown committed
885 886 887 888 889 890 891 892 893 894
/*************************************************************************
Puts an OS thread to wait if there are too many concurrent threads
(>= srv_thread_concurrency) inside InnoDB. The threads wait in a FIFO queue. */

void
srv_conc_enter_innodb(
/*==================*/
	trx_t*	trx)	/* in: transaction object associated with the
			thread */
{
unknown's avatar
unknown committed
895
	ibool			has_slept = FALSE;
896
	srv_conc_slot_t*	slot	  = NULL;
unknown's avatar
Merge  
unknown committed
897 898
	ulint			i;

unknown's avatar
unknown committed
899 900 901 902 903 904 905 906 907 908 909 910 911 912
	if (srv_thread_concurrency >= 500) {
		/* Disable the concurrency check */
	
		return;
	}

	/* If trx has 'free tickets' to enter the engine left, then use one
	such ticket */

	if (trx->n_tickets_to_enter_innodb > 0) {
		trx->n_tickets_to_enter_innodb--;

		return;
	}
unknown's avatar
Merge  
unknown committed
913 914

	os_fast_mutex_lock(&srv_conc_mutex);
unknown's avatar
unknown committed
915
retry:
unknown's avatar
unknown committed
916 917
	if (trx->declared_to_be_inside_innodb) {
	        ut_print_timestamp(stderr);
918
		fputs(
unknown's avatar
unknown committed
919
"  InnoDB: Error: trying to declare trx to enter InnoDB, but\n"
920 921 922
"InnoDB: it already is declared.\n", stderr);
		trx_print(stderr, trx);
		putc('\n', stderr);
unknown's avatar
unknown committed
923 924 925
		os_fast_mutex_unlock(&srv_conc_mutex);

		return;
unknown's avatar
unknown committed
926 927
	}

unknown's avatar
unknown committed
928
	if (srv_conc_n_threads < (lint)srv_thread_concurrency) {
unknown's avatar
Merge  
unknown committed
929

unknown's avatar
unknown committed
930 931 932 933
		srv_conc_n_threads++;
		trx->declared_to_be_inside_innodb = TRUE;
		trx->n_tickets_to_enter_innodb = SRV_FREE_TICKETS_TO_ENTER;
		
unknown's avatar
Merge  
unknown committed
934 935 936 937
		os_fast_mutex_unlock(&srv_conc_mutex);

		return;
	}
unknown's avatar
unknown committed
938

unknown's avatar
unknown committed
939 940 941
	/* If the transaction is not holding resources, let it sleep for 50
	milliseconds, and try again then */
 
unknown's avatar
unknown committed
942 943 944
	if (!has_slept && !trx->has_search_latch
	    && NULL == UT_LIST_GET_FIRST(trx->trx_locks)) {

unknown's avatar
unknown committed
945 946 947 948 949 950 951
	        has_slept = TRUE; /* We let is sleep only once to avoid
				  starvation */

		srv_conc_n_waiting_threads++;

		os_fast_mutex_unlock(&srv_conc_mutex);

unknown's avatar
unknown committed
952
		trx->op_info = "sleeping before joining InnoDB queue";
953

unknown's avatar
unknown committed
954 955 956 957 958 959 960
		/* Peter Zaitsev suggested that we take the sleep away
		altogether. But the sleep may be good in pathological
		situations of lots of thread switches. Simply put some
		threads aside for a while to reduce the number of thread
		switches. */

		os_thread_sleep(10000);
unknown's avatar
unknown committed
961

unknown's avatar
unknown committed
962
		trx->op_info = "";
unknown's avatar
unknown committed
963

unknown's avatar
unknown committed
964 965 966
		os_fast_mutex_lock(&srv_conc_mutex);

		srv_conc_n_waiting_threads--;
unknown's avatar
unknown committed
967 968

		goto retry;
unknown's avatar
unknown committed
969
	}   
unknown's avatar
unknown committed
970

unknown's avatar
unknown committed
971
	/* Too many threads inside: put the current thread to a queue */
unknown's avatar
Merge  
unknown committed
972 973 974 975 976

	for (i = 0; i < OS_THREAD_MAX_N; i++) {
		slot = srv_conc_slots + i;

		if (!slot->reserved) {
977

unknown's avatar
Merge  
unknown committed
978 979 980 981 982 983 984 985 986
			break;
		}
	}

	if (i == OS_THREAD_MAX_N) {
		/* Could not find a free wait slot, we must let the
		thread enter */

		srv_conc_n_threads++;
unknown's avatar
unknown committed
987 988
		trx->declared_to_be_inside_innodb = TRUE;
		trx->n_tickets_to_enter_innodb = 0;
unknown's avatar
Merge  
unknown committed
989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007

		os_fast_mutex_unlock(&srv_conc_mutex);

		return;
	}

	/* Release possible search system latch this thread has */
	if (trx->has_search_latch) {
		trx_search_latch_release_if_reserved(trx);
	}

	/* Add to the queue */
	slot->reserved = TRUE;
	slot->wait_ended = FALSE;
	
	UT_LIST_ADD_LAST(srv_conc_queue, srv_conc_queue, slot);

	os_event_reset(slot->event);

unknown's avatar
unknown committed
1008 1009
	srv_conc_n_waiting_threads++;

unknown's avatar
Merge  
unknown committed
1010 1011 1012 1013 1014
	os_fast_mutex_unlock(&srv_conc_mutex);

	/* Go to wait for the event; when a thread leaves InnoDB it will
	release this thread */

unknown's avatar
unknown committed
1015
	trx->op_info = "waiting in InnoDB queue";
unknown's avatar
unknown committed
1016

unknown's avatar
Merge  
unknown committed
1017 1018
	os_event_wait(slot->event);

unknown's avatar
unknown committed
1019
	trx->op_info = "";
unknown's avatar
unknown committed
1020

unknown's avatar
Merge  
unknown committed
1021 1022
	os_fast_mutex_lock(&srv_conc_mutex);

unknown's avatar
unknown committed
1023 1024
	srv_conc_n_waiting_threads--;

unknown's avatar
Merge  
unknown committed
1025 1026 1027 1028 1029 1030 1031
	/* NOTE that the thread which released this thread already
	incremented the thread counter on behalf of this thread */

	slot->reserved = FALSE;

	UT_LIST_REMOVE(srv_conc_queue, srv_conc_queue, slot);

unknown's avatar
unknown committed
1032 1033 1034
	trx->declared_to_be_inside_innodb = TRUE;
	trx->n_tickets_to_enter_innodb = SRV_FREE_TICKETS_TO_ENTER;

unknown's avatar
Merge  
unknown committed
1035 1036 1037 1038 1039 1040 1041 1042
	os_fast_mutex_unlock(&srv_conc_mutex);
}

/*************************************************************************
This lets a thread enter InnoDB regardless of the number of threads inside
InnoDB. This must be called when a thread ends a lock wait. */

void
unknown's avatar
unknown committed
1043 1044 1045 1046
srv_conc_force_enter_innodb(
/*========================*/
	trx_t*	trx)	/* in: transaction object associated with the
			thread */
unknown's avatar
Merge  
unknown committed
1047
{
unknown's avatar
unknown committed
1048 1049 1050 1051 1052
	if (srv_thread_concurrency >= 500) {
	
		return;
	}

unknown's avatar
Merge  
unknown committed
1053 1054 1055
	os_fast_mutex_lock(&srv_conc_mutex);

	srv_conc_n_threads++;
unknown's avatar
unknown committed
1056 1057
	trx->declared_to_be_inside_innodb = TRUE;
	trx->n_tickets_to_enter_innodb = 0;
unknown's avatar
Merge  
unknown committed
1058 1059 1060 1061 1062

	os_fast_mutex_unlock(&srv_conc_mutex);
}

/*************************************************************************
unknown's avatar
unknown committed
1063 1064
This must be called when a thread exits InnoDB in a lock wait or at the
end of an SQL statement. */
unknown's avatar
Merge  
unknown committed
1065 1066

void
unknown's avatar
unknown committed
1067 1068 1069 1070
srv_conc_force_exit_innodb(
/*=======================*/
	trx_t*	trx)	/* in: transaction object associated with the
			thread */
unknown's avatar
Merge  
unknown committed
1071 1072 1073
{
	srv_conc_slot_t*	slot	= NULL;

unknown's avatar
unknown committed
1074 1075 1076 1077 1078 1079 1080 1081 1082 1083
	if (srv_thread_concurrency >= 500) {
	
		return;
	}

	if (trx->declared_to_be_inside_innodb == FALSE) {
		
		return;
	}

unknown's avatar
Merge  
unknown committed
1084 1085 1086
	os_fast_mutex_lock(&srv_conc_mutex);

	srv_conc_n_threads--;
unknown's avatar
unknown committed
1087 1088
	trx->declared_to_be_inside_innodb = FALSE;
	trx->n_tickets_to_enter_innodb = 0;
unknown's avatar
Merge  
unknown committed
1089

unknown's avatar
unknown committed
1090
	if (srv_conc_n_threads < (lint)srv_thread_concurrency) {
unknown's avatar
Merge  
unknown committed
1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116
		/* Look for a slot where a thread is waiting and no other
		thread has yet released the thread */
	
		slot = UT_LIST_GET_FIRST(srv_conc_queue);

		while (slot && slot->wait_ended == TRUE) {
			slot = UT_LIST_GET_NEXT(srv_conc_queue, slot);
		}

		if (slot != NULL) {
			slot->wait_ended = TRUE;

			/* We increment the count on behalf of the released
			thread */

			srv_conc_n_threads++;
		}
	}

	os_fast_mutex_unlock(&srv_conc_mutex);

	if (slot != NULL) {
		os_event_set(slot->event);
	}
}

unknown's avatar
unknown committed
1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146
/*************************************************************************
This must be called when a thread exits InnoDB. */

void
srv_conc_exit_innodb(
/*=================*/
	trx_t*	trx)	/* in: transaction object associated with the
			thread */
{
	if (srv_thread_concurrency >= 500) {
	
		return;
	}

	if (trx->n_tickets_to_enter_innodb > 0) {
		/* We will pretend the thread is still inside InnoDB though it
		now leaves the InnoDB engine. In this way we save
		a lot of semaphore operations. srv_conc_force_exit_innodb is
		used to declare the thread definitely outside InnoDB. It
		should be called when there is a lock wait or an SQL statement
		ends. */

		return;
	}

	srv_conc_force_exit_innodb(trx);
}

/*========================================================================*/

1147
/*************************************************************************
1148
Normalizes init parameter values to use units we use inside InnoDB. */
1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164
static
ulint
srv_normalize_init_values(void)
/*===========================*/
				/* out: DB_SUCCESS or error code */
{
	ulint	n;
	ulint	i;

	n = srv_n_data_files;
	
	for (i = 0; i < n; i++) {
		srv_data_file_sizes[i] = srv_data_file_sizes[i]
					* ((1024 * 1024) / UNIV_PAGE_SIZE);
	}		

unknown's avatar
unknown committed
1165 1166 1167
	srv_last_file_size_max = srv_last_file_size_max
					* ((1024 * 1024) / UNIV_PAGE_SIZE);
		
1168 1169 1170 1171
	srv_log_file_size = srv_log_file_size / UNIV_PAGE_SIZE;

	srv_log_buffer_size = srv_log_buffer_size / UNIV_PAGE_SIZE;

unknown's avatar
unknown committed
1172 1173 1174
	srv_pool_size = srv_pool_size / (UNIV_PAGE_SIZE / 1024);

	srv_awe_window_size = srv_awe_window_size / UNIV_PAGE_SIZE;
1175
	
unknown's avatar
unknown committed
1176 1177 1178 1179 1180 1181 1182
	if (srv_use_awe) {
	        /* If we are using AWE we must save memory in the 32-bit
		address space of the process, and cannot bind the lock
		table size to the real buffer pool size. */

	        srv_lock_table_size = 20 * srv_awe_window_size;
	} else {
1183
	        srv_lock_table_size = 5 * srv_pool_size;
unknown's avatar
unknown committed
1184
	}
1185 1186 1187 1188 1189

	return(DB_SUCCESS);
}

/*************************************************************************
1190
Boots the InnoDB server. */
1191 1192 1193 1194 1195 1196 1197 1198 1199

ulint
srv_boot(void)
/*==========*/
			/* out: DB_SUCCESS or error code */
{
	ulint	err;

	/* Transform the init parameter values given by MySQL to
1200
	use units we use inside InnoDB: */
1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221
	
	err = srv_normalize_init_values();

	if (err != DB_SUCCESS) {
		return(err);
	}
	
	/* Initialize synchronization primitives, memory management, and thread
	local storage */
	
	srv_general_init();

	/* Initialize this module */

	srv_init();

	return(DB_SUCCESS);
}

/*************************************************************************
Reserves a slot in the thread table for the current MySQL OS thread.
unknown's avatar
unknown committed
1222
NOTE! The kernel mutex has to be reserved by the caller! */
1223 1224 1225 1226 1227 1228 1229 1230 1231
static
srv_slot_t*
srv_table_reserve_slot_for_mysql(void)
/*==================================*/
			/* out: reserved slot */
{
	srv_slot_t*	slot;
	ulint		i;

1232
#ifdef UNIV_SYNC_DEBUG
unknown's avatar
unknown committed
1233
	ut_ad(mutex_own(&kernel_mutex));
1234
#endif /* UNIV_SYNC_DEBUG */
unknown's avatar
unknown committed
1235

1236 1237 1238 1239 1240
	i = 0;
	slot = srv_mysql_table + i;

	while (slot->in_use) {
		i++;
unknown's avatar
unknown committed
1241 1242 1243 1244 1245 1246 1247 1248 1249

		if (i >= OS_THREAD_MAX_N) {

		        ut_print_timestamp(stderr);

		        fprintf(stderr,
"  InnoDB: There appear to be %lu MySQL threads currently waiting\n"
"InnoDB: inside InnoDB, which is the upper limit. Cannot continue operation.\n"
"InnoDB: We intentionally generate a seg fault to print a stack trace\n"
1250
"InnoDB: on Linux. But first we print a list of waiting threads.\n", (ulong) i);
unknown's avatar
unknown committed
1251 1252 1253 1254 1255 1256 1257

			for (i = 0; i < OS_THREAD_MAX_N; i++) {

			        slot = srv_mysql_table + i;

			        fprintf(stderr,
"Slot %lu: thread id %lu, type %lu, in use %lu, susp %lu, time %lu\n",
1258 1259 1260 1261
				  (ulong) i, (ulong) os_thread_pf(slot->id),
				  (ulong) slot->type, (ulong) slot->in_use,
				  (ulong) slot->suspended,
			  (ulong) difftime(ut_time(), slot->suspend_time));
unknown's avatar
unknown committed
1262 1263
			}

1264
		        ut_error;
unknown's avatar
unknown committed
1265
		}
1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279
		
		slot = srv_mysql_table + i;
	}

	ut_a(slot->in_use == FALSE);
	
	slot->in_use = TRUE;
	slot->id = os_thread_get_curr_id();
	slot->handle = os_thread_get_curr();

	return(slot);
}

/*******************************************************************
unknown's avatar
unknown committed
1280 1281 1282 1283 1284
Puts a MySQL OS thread to wait for a lock to be released. If an error
occurs during the wait trx->error_state associated with thr is
!= DB_SUCCESS when we return. DB_LOCK_WAIT_TIMEOUT and DB_DEADLOCK
are possible errors. DB_DEADLOCK is returned if selective deadlock
resolution chose this transaction as a victim. */
1285

unknown's avatar
unknown committed
1286
void
1287 1288
srv_suspend_mysql_thread(
/*=====================*/
unknown's avatar
unknown committed
1289 1290
	que_thr_t*	thr)	/* in: query thread associated with the MySQL
				OS thread */
1291 1292 1293 1294
{
	srv_slot_t*	slot;
	os_event_t	event;
	double		wait_time;
unknown's avatar
unknown committed
1295
	trx_t*		trx;
unknown's avatar
unknown committed
1296 1297
	ibool		had_dict_lock			= FALSE;
	ibool		was_declared_inside_innodb	= FALSE;
unknown's avatar
unknown committed
1298
	
1299
#ifdef UNIV_SYNC_DEBUG
1300
	ut_ad(!mutex_own(&kernel_mutex));
1301
#endif /* UNIV_SYNC_DEBUG */
1302

unknown's avatar
unknown committed
1303 1304
	trx = thr_get_trx(thr);
	
1305 1306 1307 1308
	os_event_set(srv_lock_timeout_thread_event);

	mutex_enter(&kernel_mutex);

unknown's avatar
unknown committed
1309 1310
	trx->error_state = DB_SUCCESS;

1311 1312
	if (thr->state == QUE_THR_RUNNING) {

unknown's avatar
unknown committed
1313 1314 1315 1316 1317 1318 1319 1320 1321 1322
		ut_ad(thr->is_active == TRUE);
	
		/* The lock has already been released or this transaction
		was chosen as a deadlock victim: no need to suspend */

		if (trx->was_chosen_as_deadlock_victim) {

			trx->error_state = DB_DEADLOCK;
			trx->was_chosen_as_deadlock_victim = FALSE;
		}
1323 1324 1325

		mutex_exit(&kernel_mutex);

unknown's avatar
unknown committed
1326
		return;
1327 1328
	}
	
unknown's avatar
unknown committed
1329 1330
	ut_ad(thr->is_active == FALSE);

1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346
	slot = srv_table_reserve_slot_for_mysql();

	event = slot->event;
	
	slot->thr = thr;

	os_event_reset(event);	

	slot->suspend_time = ut_time();

	/* Wake the lock timeout monitor thread, if it is suspended */

	os_event_set(srv_lock_timeout_thread_event);
	
	mutex_exit(&kernel_mutex);

unknown's avatar
unknown committed
1347 1348 1349
	if (trx->declared_to_be_inside_innodb) {

		was_declared_inside_innodb = TRUE;
unknown's avatar
Merge  
unknown committed
1350
	
unknown's avatar
unknown committed
1351 1352 1353
		/* We must declare this OS thread to exit InnoDB, since a
		possible other thread holding a lock which this thread waits
		for must be allowed to enter, sooner or later */
unknown's avatar
Merge  
unknown committed
1354
	
unknown's avatar
unknown committed
1355 1356
		srv_conc_force_exit_innodb(trx);
	}
unknown's avatar
Merge  
unknown committed
1357

unknown's avatar
unknown committed
1358
	/* Release possible foreign key check latch */
unknown's avatar
unknown committed
1359 1360 1361
	if (trx->dict_operation_lock_mode == RW_S_LATCH) {

		had_dict_lock = TRUE;
unknown's avatar
unknown committed
1362

unknown's avatar
unknown committed
1363
		row_mysql_unfreeze_data_dictionary(trx);
unknown's avatar
unknown committed
1364 1365
	}

unknown's avatar
unknown committed
1366 1367
	ut_a(trx->dict_operation_lock_mode == 0);

1368 1369 1370 1371
	/* Wait for the release */
	
	os_event_wait(event);

unknown's avatar
unknown committed
1372
	if (had_dict_lock) {
unknown's avatar
unknown committed
1373

unknown's avatar
unknown committed
1374
		row_mysql_freeze_data_dictionary(trx);
unknown's avatar
unknown committed
1375 1376
	}

unknown's avatar
unknown committed
1377 1378 1379
	if (was_declared_inside_innodb) {

		/* Return back inside InnoDB */
unknown's avatar
Merge  
unknown committed
1380
	
unknown's avatar
unknown committed
1381 1382
		srv_conc_force_enter_innodb(trx);
	}
unknown's avatar
Merge  
unknown committed
1383

1384 1385 1386 1387 1388 1389 1390 1391
	mutex_enter(&kernel_mutex);

	/* Release the slot for others to use */
	
	slot->in_use = FALSE;

	wait_time = ut_difftime(ut_time(), slot->suspend_time);
	
unknown's avatar
unknown committed
1392 1393 1394 1395 1396 1397
	if (trx->was_chosen_as_deadlock_victim) {

		trx->error_state = DB_DEADLOCK;
		trx->was_chosen_as_deadlock_victim = FALSE;
	}

1398 1399 1400 1401 1402
	mutex_exit(&kernel_mutex);

	if (srv_lock_wait_timeout < 100000000 && 
	    			wait_time > (double)srv_lock_wait_timeout) {

unknown's avatar
unknown committed
1403 1404
	    	trx->error_state = DB_LOCK_WAIT_TIMEOUT;
	}
1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419
}

/************************************************************************
Releases a MySQL OS thread waiting for a lock to be released, if the
thread is already suspended. */

void
srv_release_mysql_thread_if_suspended(
/*==================================*/
	que_thr_t*	thr)	/* in: query thread associated with the
				MySQL OS thread  */
{
	srv_slot_t*	slot;
	ulint		i;
	
1420
#ifdef UNIV_SYNC_DEBUG
1421
	ut_ad(mutex_own(&kernel_mutex));
1422
#endif /* UNIV_SYNC_DEBUG */
1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439

	for (i = 0; i < OS_THREAD_MAX_N; i++) {

		slot = srv_mysql_table + i;

		if (slot->in_use && slot->thr == thr) {
			/* Found */

			os_event_set(slot->event);

			return;
		}
	}

	/* not found */
}

unknown's avatar
unknown committed
1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467
/**********************************************************************
Refreshes the values used to calculate per-second averages. */
static
void
srv_refresh_innodb_monitor_stats(void)
/*==================================*/
{
	mutex_enter(&srv_innodb_monitor_mutex);

	srv_last_monitor_time = time(NULL);

	os_aio_refresh_stats();

	btr_cur_n_sea_old = btr_cur_n_sea;
	btr_cur_n_non_sea_old = btr_cur_n_non_sea;

	log_refresh_stats();
	
	buf_refresh_io_stats();

	srv_n_rows_inserted_old = srv_n_rows_inserted;
	srv_n_rows_updated_old = srv_n_rows_updated;
	srv_n_rows_deleted_old = srv_n_rows_deleted;
	srv_n_rows_read_old = srv_n_rows_read;

	mutex_exit(&srv_innodb_monitor_mutex);
}

unknown's avatar
unknown committed
1468
/**********************************************************************
1469
Outputs to a file the output of the InnoDB Monitor. */
1470

unknown's avatar
unknown committed
1471
void
1472 1473 1474
srv_printf_innodb_monitor(
/*======================*/
	FILE*	file)	/* in: output stream */
1475
{
unknown's avatar
unknown committed
1476 1477
	double	time_elapsed;
	time_t	current_time;
unknown's avatar
unknown committed
1478
	ulint   n_reserved;
unknown's avatar
Merge  
unknown committed
1479

unknown's avatar
unknown committed
1480
	mutex_enter(&srv_innodb_monitor_mutex);
1481

unknown's avatar
unknown committed
1482
	current_time = time(NULL);
1483

unknown's avatar
unknown committed
1484 1485 1486
	/* We add 0.001 seconds to time_elapsed to prevent division
	by zero if two users happen to call SHOW INNODB STATUS at the same
	time */
1487
	
unknown's avatar
unknown committed
1488 1489
	time_elapsed = difftime(current_time, srv_last_monitor_time)
			+ 0.001;
1490

unknown's avatar
unknown committed
1491
	srv_last_monitor_time = time(NULL);
1492

1493 1494
	rewind(file);
	fputs("\n=====================================\n", file);
unknown's avatar
unknown committed
1495

1496 1497 1498 1499 1500 1501
	ut_print_timestamp(file);
	fprintf(file,
		" INNODB MONITOR OUTPUT\n"
		"=====================================\n"
		"Per second averages calculated from the last %lu seconds\n",
		(ulong)time_elapsed);
unknown's avatar
unknown committed
1502

1503 1504 1505 1506
	fputs("----------\n"
		"SEMAPHORES\n"
		"----------\n", file);
	sync_print(file);
unknown's avatar
unknown committed
1507

unknown's avatar
unknown committed
1508 1509 1510 1511 1512 1513 1514
	/* Conceptually, srv_innodb_monitor_mutex has a very high latching
	order level in sync0sync.h, while dict_foreign_err_mutex has a very
	low level 135. Therefore we can reserve the latter mutex here without
	a danger of a deadlock of threads. */

	mutex_enter(&dict_foreign_err_mutex);

1515 1516 1517 1518 1519 1520
	if (ftell(dict_foreign_err_file) != 0L) {
		fputs("------------------------\n"
			"LATEST FOREIGN KEY ERROR\n"
			"------------------------\n", file);
		ut_copy_file(file, dict_foreign_err_file);
	}
unknown's avatar
unknown committed
1521

unknown's avatar
unknown committed
1522
	mutex_exit(&dict_foreign_err_mutex);
1523

1524 1525 1526 1527 1528
	lock_print_info(file);
	fputs("--------\n"
		"FILE I/O\n"
		"--------\n", file);
	os_aio_print(file);
1529

1530 1531 1532 1533 1534 1535 1536 1537
	fputs("-------------------------------------\n"
		"INSERT BUFFER AND ADAPTIVE HASH INDEX\n"
		"-------------------------------------\n", file);
	ibuf_print(file);

	ha_print_info(file, btr_search_sys->hash_index);

	fprintf(file,
unknown's avatar
unknown committed
1538 1539 1540 1541 1542
		"%.2f hash searches/s, %.2f non-hash searches/s\n",
			(btr_cur_n_sea - btr_cur_n_sea_old)
						/ time_elapsed,
			(btr_cur_n_non_sea - btr_cur_n_non_sea_old)
						/ time_elapsed);
unknown's avatar
unknown committed
1543 1544
	btr_cur_n_sea_old = btr_cur_n_sea;
	btr_cur_n_non_sea_old = btr_cur_n_non_sea;
unknown's avatar
unknown committed
1545

1546
	fputs("---\n"
1547
		       "LOG\n"
1548 1549 1550 1551
		"---\n", file);
	log_print(file);

	fputs("----------------------\n"
1552
		       "BUFFER POOL AND MEMORY\n"
1553 1554
		"----------------------\n", file);
	fprintf(file,
unknown's avatar
unknown committed
1555
	"Total memory allocated " ULINTPF
unknown's avatar
unknown committed
1556
	"; in additional pool allocated " ULINTPF "\n",
unknown's avatar
unknown committed
1557 1558
				ut_total_allocated_memory,
				mem_pool_get_reserved(mem_comm_pool));
1559

unknown's avatar
unknown committed
1560
	if (srv_use_awe) {
unknown's avatar
unknown committed
1561
		fprintf(file,
unknown's avatar
unknown committed
1562
	"In addition to that %lu MB of AWE memory allocated\n",
unknown's avatar
unknown committed
1563
		(ulong) (srv_pool_size / ((1024 * 1024) / UNIV_PAGE_SIZE)));
unknown's avatar
unknown committed
1564 1565
	}
	
1566
	buf_print_io(file);
1567

1568 1569 1570 1571
	fputs("--------------\n"
		"ROW OPERATIONS\n"
		"--------------\n", file);
	fprintf(file, "%ld queries inside InnoDB, %lu queries in queue\n",
unknown's avatar
unknown committed
1572 1573
       		       (long) srv_conc_n_threads,
		       (ulong) srv_conc_n_waiting_threads);
unknown's avatar
unknown committed
1574 1575
        n_reserved = fil_space_get_n_reserved_extents(0);
        if (n_reserved > 0) {
unknown's avatar
unknown committed
1576
                fprintf(file,
unknown's avatar
unknown committed
1577
        "%lu tablespace extents now reserved for B-tree split operations\n",
1578
                                                    (ulong) n_reserved);
unknown's avatar
unknown committed
1579
        }
1580

unknown's avatar
unknown committed
1581
#ifdef UNIV_LINUX
1582
	fprintf(file, "Main thread process no. %lu, id %lu, state: %s\n",
1583 1584 1585
		       (ulong) srv_main_thread_process_no,
		       (ulong) srv_main_thread_id,
		       srv_main_thread_op_info);
unknown's avatar
unknown committed
1586
#else
1587
	fprintf(file, "Main thread id %lu, state: %s\n",
1588
			(ulong) srv_main_thread_id,
unknown's avatar
unknown committed
1589
			srv_main_thread_op_info);
unknown's avatar
unknown committed
1590
#endif
1591
	fprintf(file,
unknown's avatar
unknown committed
1592 1593 1594 1595 1596 1597
	"Number of rows inserted " ULINTPF
	", updated " ULINTPF ", deleted " ULINTPF ", read " ULINTPF "\n",
			srv_n_rows_inserted, 
			srv_n_rows_updated, 
			srv_n_rows_deleted, 
			srv_n_rows_read);
1598
	fprintf(file,
1599 1600 1601 1602 1603 1604 1605 1606 1607 1608
	"%.2f inserts/s, %.2f updates/s, %.2f deletes/s, %.2f reads/s\n",
			(srv_n_rows_inserted - srv_n_rows_inserted_old)
						/ time_elapsed,
			(srv_n_rows_updated - srv_n_rows_updated_old)
						/ time_elapsed,
			(srv_n_rows_deleted - srv_n_rows_deleted_old)
						/ time_elapsed,
			(srv_n_rows_read - srv_n_rows_read_old)
						/ time_elapsed);

unknown's avatar
unknown committed
1609 1610 1611 1612
	srv_n_rows_inserted_old = srv_n_rows_inserted;
	srv_n_rows_updated_old = srv_n_rows_updated;
	srv_n_rows_deleted_old = srv_n_rows_deleted;
	srv_n_rows_read_old = srv_n_rows_read;
1613

1614
	fputs("----------------------------\n"
1615
		       "END OF INNODB MONITOR OUTPUT\n"
1616
		"============================\n", file);
1617

unknown's avatar
unknown committed
1618
	mutex_exit(&srv_innodb_monitor_mutex);
1619
	fflush(file);
unknown's avatar
unknown committed
1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633
}

/*************************************************************************
A thread which wakes up threads whose lock wait may have lasted too long.
This also prints the info output by various InnoDB monitors. */

#ifndef __WIN__
void*
#else
ulint
#endif
srv_lock_timeout_and_monitor_thread(
/*================================*/
			/* out: a dummy parameter */
1634 1635
	void*	arg __attribute__((unused)))
			/* in: a dummy parameter required by
unknown's avatar
unknown committed
1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646
			os_thread_create */
{
	srv_slot_t*	slot;
	double		time_elapsed;
	time_t          current_time;
	time_t		last_table_monitor_time;
	time_t		last_monitor_time;
	ibool		some_waits;
	double		wait_time;
	ulint		i;

1647
#ifdef UNIV_DEBUG_THREAD_CREATION
1648
	fprintf(stderr, "Lock timeout thread starts, id %lu\n",
unknown's avatar
unknown committed
1649
			     os_thread_pf(os_thread_get_curr_id()));
1650
#endif
unknown's avatar
unknown committed
1651 1652 1653 1654 1655 1656 1657 1658 1659 1660
	UT_NOT_USED(arg);
	srv_last_monitor_time = time(NULL);
	last_table_monitor_time = time(NULL);
	last_monitor_time = time(NULL);
loop:
	srv_lock_timeout_and_monitor_active = TRUE;

	/* When someone is waiting for a lock, we wake up every second
	and check if a timeout has passed for a lock wait */

unknown's avatar
unknown committed
1661
	os_thread_sleep(1000000);
unknown's avatar
unknown committed
1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676

	/* In case mutex_exit is not a memory barrier, it is
	theoretically possible some threads are left waiting though
	the semaphore is already released. Wake up those threads: */
	
	sync_arr_wake_threads_if_sema_free();

	current_time = time(NULL);

	time_elapsed = difftime(current_time, last_monitor_time);
	
	if (time_elapsed > 15) {
	    last_monitor_time = time(NULL);

	    if (srv_print_innodb_monitor) {
1677 1678
		srv_printf_innodb_monitor(stderr);
	    }
unknown's avatar
unknown committed
1679

1680 1681 1682
	    mutex_enter(&srv_monitor_file_mutex);
	    rewind(srv_monitor_file);
	    srv_printf_innodb_monitor(srv_monitor_file);
1683
	    os_file_set_eof(srv_monitor_file);
1684
	    mutex_exit(&srv_monitor_file_mutex);
1685

1686 1687
	    if (srv_print_innodb_tablespace_monitor
		&& difftime(current_time, last_table_monitor_time) > 60) {
unknown's avatar
unknown committed
1688 1689 1690

		last_table_monitor_time = time(NULL);	

1691 1692
		fputs("================================================\n",
			stderr);
1693

1694
		ut_print_timestamp(stderr);
1695

1696 1697 1698
		fputs(" INNODB TABLESPACE MONITOR OUTPUT\n"
			"================================================\n",
			stderr);
1699 1700
	       
		fsp_print(0);
1701
		fputs("Validating tablespace\n", stderr);
1702
		fsp_validate(0);
1703 1704
		fputs("Validation ok\n"
			"---------------------------------------\n"
1705
	       		"END OF INNODB TABLESPACE MONITOR OUTPUT\n"
1706 1707
			"=======================================\n",
			stderr);
1708 1709
	    }

unknown's avatar
unknown committed
1710
	    if (srv_print_innodb_table_monitor
1711
		&& difftime(current_time, last_table_monitor_time) > 60) {
unknown's avatar
unknown committed
1712 1713

		last_table_monitor_time = time(NULL);	
1714

1715
		fputs("===========================================\n", stderr);
1716

1717
		ut_print_timestamp(stderr);
1718

1719 1720 1721
		fputs(" INNODB TABLE MONITOR OUTPUT\n"
			"===========================================\n",
			stderr);
1722 1723
	    	dict_print();

1724
		fputs("-----------------------------------\n"
1725
	       		"END OF INNODB TABLE MONITOR OUTPUT\n"
1726 1727
			"==================================\n",
			stderr);
1728 1729 1730
	    }
	}

1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750
	mutex_enter(&kernel_mutex);

	some_waits = FALSE;

	/* Check of all slots if a thread is waiting there, and if it
	has exceeded the time limit */
	
	for (i = 0; i < OS_THREAD_MAX_N; i++) {

		slot = srv_mysql_table + i;

		if (slot->in_use) {
			some_waits = TRUE;

			wait_time = ut_difftime(ut_time(), slot->suspend_time);
			
			if (srv_lock_wait_timeout < 100000000 && 
	    			(wait_time > (double) srv_lock_wait_timeout
						|| wait_time < 0)) {

unknown's avatar
Merge  
unknown committed
1751
				/* Timeout exceeded or a wrap-around in system
1752
				time counter: cancel the lock request queued
1753
				by the transaction and release possible
unknown's avatar
unknown committed
1754 1755 1756 1757 1758 1759 1760 1761
				other transactions waiting behind; it is
				possible that the lock has already been
				granted: in that case do nothing */

			        if (thr_get_trx(slot->thr)->wait_lock) {
				        lock_cancel_waiting_and_release(
				          thr_get_trx(slot->thr)->wait_lock);
			        }
1762 1763 1764 1765 1766 1767 1768 1769
			}
		}
	}

	os_event_reset(srv_lock_timeout_thread_event);

	mutex_exit(&kernel_mutex);

unknown's avatar
Merge  
unknown committed
1770 1771 1772 1773
	if (srv_shutdown_state >= SRV_SHUTDOWN_CLEANUP) {
		goto exit_func;
	}

1774 1775 1776 1777
	if (some_waits || srv_print_innodb_monitor
			|| srv_print_innodb_lock_monitor
			|| srv_print_innodb_tablespace_monitor
			|| srv_print_innodb_table_monitor) {
1778 1779 1780
		goto loop;
	}

1781 1782
	/* No one was waiting for a lock and no monitor was active:
	suspend this thread */
unknown's avatar
Merge  
unknown committed
1783 1784 1785

	srv_lock_timeout_and_monitor_active = FALSE;

1786 1787 1788
#if 0
	/* The following synchronisation is disabled, since
	the InnoDB monitor output is to be updated every 15 seconds. */
1789
	os_event_wait(srv_lock_timeout_thread_event);
1790
#endif
1791 1792
	goto loop;

unknown's avatar
Merge  
unknown committed
1793 1794 1795
exit_func:
	srv_lock_timeout_and_monitor_active = FALSE;

1796 1797 1798 1799
	/* We count the number of threads in os_thread_exit(). A created
	thread should always use that to exit and not use return() to exit. */

	os_thread_exit(NULL);
1800
#ifndef __WIN__
1801
	return(NULL);
1802
#else
1803
	return(0);
1804
#endif
1805 1806
}

1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818
/*************************************************************************
A thread which prints warnings about semaphore waits which have lasted
too long. These can be used to track bugs which cause hangs. */

#ifndef __WIN__
void*
#else
ulint
#endif
srv_error_monitor_thread(
/*=====================*/
			/* out: a dummy parameter */
1819 1820
	void*	arg __attribute__((unused)))
			/* in: a dummy parameter required by
1821 1822
			os_thread_create */
{
1823 1824
	/* number of successive fatal timeouts observed */
	ulint	fatal_cnt	= 0;
unknown's avatar
unknown committed
1825 1826
	dulint	old_lsn;
	dulint	new_lsn;
unknown's avatar
unknown committed
1827

unknown's avatar
unknown committed
1828 1829
	old_lsn = srv_start_lsn;

1830
#ifdef UNIV_DEBUG_THREAD_CREATION
1831
	fprintf(stderr, "Error monitor thread starts, id %lu\n",
unknown's avatar
unknown committed
1832
			      os_thread_pf(os_thread_get_curr_id()));
1833
#endif
1834
loop:
unknown's avatar
Merge  
unknown committed
1835 1836
	srv_error_monitor_active = TRUE;

unknown's avatar
unknown committed
1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847
	/* Try to track a strange bug reported by Harald Fuchs and others,
	where the lsn seems to decrease at times */

	new_lsn = log_get_lsn();

	if (ut_dulint_cmp(new_lsn, old_lsn) < 0) {
		ut_print_timestamp(stderr);
		fprintf(stderr,
"  InnoDB: Error: old log sequence number %lu %lu was greater\n"
"InnoDB: than the new log sequence number %lu %lu!\n"
"InnoDB: Please send a bug report to mysql@lists.mysql.com\n",
1848 1849 1850 1851
		(ulong) ut_dulint_get_high(old_lsn),
		(ulong) ut_dulint_get_low(old_lsn),
		(ulong) ut_dulint_get_high(new_lsn),
		(ulong) ut_dulint_get_low(new_lsn));
unknown's avatar
unknown committed
1852 1853 1854 1855
	}

	old_lsn = new_lsn;

unknown's avatar
unknown committed
1856 1857 1858
	if (difftime(time(NULL), srv_last_monitor_time) > 60) {
		/* We referesh InnoDB Monitor values so that averages are
		printed from at most 60 last seconds */
1859

unknown's avatar
unknown committed
1860 1861 1862
		srv_refresh_innodb_monitor_stats();
	}

1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876
	if (sync_array_print_long_waits()) {
		fatal_cnt++;
		if (fatal_cnt > 5) {

			fprintf(stderr,
"InnoDB: Error: semaphore wait has lasted > %lu seconds\n"
"InnoDB: We intentionally crash the server, because it appears to be hung.\n",
				srv_fatal_semaphore_wait_threshold);

			ut_error;
		}
	} else {
		fatal_cnt = 0;
	}
unknown's avatar
unknown committed
1877

1878
	/* Flush stderr so that a database user gets the output
unknown's avatar
unknown committed
1879 1880 1881 1882
	to possible MySQL error file */

	fflush(stderr);

unknown's avatar
unknown committed
1883 1884
	os_thread_sleep(2000000);

unknown's avatar
Merge  
unknown committed
1885 1886 1887 1888 1889 1890
	if (srv_shutdown_state < SRV_SHUTDOWN_LAST_PHASE) {

		goto loop;
	}

	srv_error_monitor_active = FALSE;
1891

1892 1893 1894
	/* We count the number of threads in os_thread_exit(). A created
	thread should always use that to exit and not use return() to exit. */

unknown's avatar
unknown committed
1895 1896
	os_thread_exit(NULL);

1897
#ifndef __WIN__
1898
	return(NULL);
1899 1900 1901 1902 1903
#else
	return(0);
#endif
}

1904
/***********************************************************************
1905
Tells the InnoDB server that there has been activity in the database
1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926
and wakes up the master thread if it is suspended (not sleeping). Used
in the MySQL interface. Note that there is a small chance that the master
thread stays suspended (we do not protect our operation with the kernel
mutex, for performace reasons). */

void
srv_active_wake_master_thread(void)
/*===============================*/
{
	srv_activity_count++;
			
	if (srv_n_threads_active[SRV_MASTER] == 0) {

		mutex_enter(&kernel_mutex);

		srv_release_threads(SRV_MASTER, 1);

		mutex_exit(&kernel_mutex);
	}
}

unknown's avatar
unknown committed
1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942
/***********************************************************************
Wakes up the master thread if it is suspended or being suspended. */

void
srv_wake_master_thread(void)
/*========================*/
{
	srv_activity_count++;
			
	mutex_enter(&kernel_mutex);

	srv_release_threads(SRV_MASTER, 1);

	mutex_exit(&kernel_mutex);
}

1943 1944 1945
/*************************************************************************
The master thread controlling the server. */

1946 1947 1948
#ifndef __WIN__
void*
#else
1949
ulint
1950
#endif
1951 1952 1953
srv_master_thread(
/*==============*/
			/* out: a dummy parameter */
1954 1955
	void*	arg __attribute__((unused)))
			/* in: a dummy parameter required by
1956 1957 1958
			os_thread_create */
{
	os_event_t	event;
1959 1960
	time_t          last_flush_time;
	time_t          current_time;
1961 1962 1963 1964 1965
	ulint		old_activity_count;
	ulint		n_pages_purged;
	ulint		n_bytes_merged;
	ulint		n_pages_flushed;
	ulint		n_bytes_archived;
unknown's avatar
unknown committed
1966
	ulint		n_tables_to_drop;
1967 1968 1969 1970
	ulint		n_ios;
	ulint		n_ios_old;
	ulint		n_ios_very_old;
	ulint		n_pend_ios;
unknown's avatar
unknown committed
1971
	ibool		skip_sleep	= FALSE;
1972 1973
	ulint		i;
	
1974
#ifdef UNIV_DEBUG_THREAD_CREATION
1975
	fprintf(stderr, "Master thread starts, id %lu\n",
unknown's avatar
unknown committed
1976
			      os_thread_pf(os_thread_get_curr_id()));
1977
#endif
unknown's avatar
unknown committed
1978 1979 1980
	srv_main_thread_process_no = os_proc_get_number();
	srv_main_thread_id = os_thread_pf(os_thread_get_curr_id());
	
1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
	srv_table_reserve_slot(SRV_MASTER);	

	mutex_enter(&kernel_mutex);

	srv_n_threads_active[SRV_MASTER]++;

	mutex_exit(&kernel_mutex);

	os_event_set(srv_sys->operational);
loop:
1991 1992 1993 1994
	/*****************************************************************/
	/* ---- When there is database activity by users, we cycle in this
	loop */

unknown's avatar
unknown committed
1995
	srv_main_thread_op_info = "reserving kernel mutex";
1996 1997 1998

	n_ios_very_old = log_sys->n_log_ios + buf_pool->n_pages_read
						+ buf_pool->n_pages_written;
1999 2000
	mutex_enter(&kernel_mutex);

2001
	/* Store the user activity counter at the start of this loop */
2002 2003 2004 2005
	old_activity_count = srv_activity_count;

	mutex_exit(&kernel_mutex);

2006 2007 2008 2009 2010 2011 2012 2013
	if (srv_force_recovery >= SRV_FORCE_NO_BACKGROUND) {

		goto suspend_thread;
	}

	/* ---- We run the following loop approximately once per second
	when there is database activity */

unknown's avatar
unknown committed
2014
	skip_sleep = FALSE;
2015 2016

	for (i = 0; i < 10; i++) {
2017 2018
		n_ios_old = log_sys->n_log_ios + buf_pool->n_pages_read
						+ buf_pool->n_pages_written;
unknown's avatar
unknown committed
2019
		srv_main_thread_op_info = "sleeping";
unknown's avatar
unknown committed
2020 2021 2022 2023 2024 2025 2026
		
		if (!skip_sleep) {

		        os_thread_sleep(1000000);
		}

		skip_sleep = FALSE;
2027

unknown's avatar
unknown committed
2028 2029 2030 2031
		/* ALTER TABLE in MySQL requires on Unix that the table handler
		can drop tables lazily after there no longer are SELECT
		queries to them. */

unknown's avatar
unknown committed
2032
		srv_main_thread_op_info = "doing background drop tables";
unknown's avatar
unknown committed
2033 2034 2035

		row_drop_tables_for_mysql_in_background();

unknown's avatar
unknown committed
2036
		srv_main_thread_op_info = "";
unknown's avatar
unknown committed
2037

unknown's avatar
unknown committed
2038
		if (srv_fast_shutdown && srv_shutdown_state > 0) {
2039

unknown's avatar
unknown committed
2040
			goto background_loop;
2041 2042
		}

unknown's avatar
unknown committed
2043 2044 2045 2046
		/* We flush the log once in a second even if no commit
		is issued or the we have specified in my.cnf no flush
		at transaction commit */

unknown's avatar
unknown committed
2047
		srv_main_thread_op_info = "flushing log";
unknown's avatar
unknown committed
2048
		log_buffer_flush_to_disk();
unknown's avatar
unknown committed
2049

unknown's avatar
unknown committed
2050
		srv_main_thread_op_info = "making checkpoint";
unknown's avatar
unknown committed
2051 2052
		log_free_check();

2053
		/* If there were less than 5 i/os during the
2054 2055 2056 2057 2058 2059 2060 2061
		one second sleep, we assume that there is free
		disk i/o capacity available, and it makes sense to
		do an insert buffer merge. */

		n_pend_ios = buf_get_n_pending_ios()
						+ log_sys->n_pending_writes;
		n_ios = log_sys->n_log_ios + buf_pool->n_pages_read
						+ buf_pool->n_pages_written;
2062
		if (n_pend_ios < 3 && (n_ios - n_ios_old < 5)) {
unknown's avatar
unknown committed
2063
			srv_main_thread_op_info = "doing insert buffer merge";
2064 2065
			ibuf_contract_for_n_pages(TRUE, 5);

unknown's avatar
unknown committed
2066
			srv_main_thread_op_info = "flushing log";
unknown's avatar
unknown committed
2067 2068

			log_buffer_flush_to_disk();
2069
		}
unknown's avatar
Merge  
unknown committed
2070

2071 2072 2073 2074 2075 2076 2077 2078
		if (buf_get_modified_ratio_pct() >
				             srv_max_buf_pool_modified_pct) {

			/* Try to keep the number of modified pages in the
			buffer pool under the limit wished by the user */
			
			n_pages_flushed = buf_flush_batch(BUF_FLUSH_LIST, 100,
							  ut_dulint_max);
unknown's avatar
unknown committed
2079 2080 2081 2082 2083 2084 2085

		        /* If we had to do the flush, it may have taken
			even more than 1 second, and also, there may be more
			to flush. Do not sleep 1 second during the next
			iteration of this loop. */
			     
			skip_sleep = TRUE;
unknown's avatar
Merge  
unknown committed
2086 2087
		}

2088 2089
		if (srv_activity_count == old_activity_count) {

2090 2091
			/* There is no user activity at the moment, go to
			the background loop */
2092 2093 2094 2095 2096

			goto background_loop;
		}
	}

2097 2098
	/* ---- We perform the following code approximately once per
	10 seconds when there is database activity */
2099

unknown's avatar
unknown committed
2100 2101 2102 2103 2104
#ifdef MEM_PERIODIC_CHECK
	/* Check magic numbers of every allocated mem block once in 10
	seconds */
	mem_validate_all_blocks();
#endif	
2105 2106
	/* If there were less than 200 i/os during the 10 second period,
	we assume that there is free disk i/o capacity available, and it
2107
	makes sense to flush 100 pages. */
2108 2109 2110 2111 2112 2113

	n_pend_ios = buf_get_n_pending_ios() + log_sys->n_pending_writes;
	n_ios = log_sys->n_log_ios + buf_pool->n_pages_read
						+ buf_pool->n_pages_written;
	if (n_pend_ios < 3 && (n_ios - n_ios_very_old < 200)) {

unknown's avatar
unknown committed
2114
		srv_main_thread_op_info = "flushing buffer pool pages";
unknown's avatar
unknown committed
2115
		buf_flush_batch(BUF_FLUSH_LIST, 100, ut_dulint_max);
2116

unknown's avatar
unknown committed
2117
		srv_main_thread_op_info = "flushing log";
unknown's avatar
unknown committed
2118
		log_buffer_flush_to_disk();
2119 2120 2121 2122 2123
	}

	/* We run a batch of insert buffer merge every 10 seconds,
	even if the server were active */

unknown's avatar
unknown committed
2124
	srv_main_thread_op_info = "doing insert buffer merge";
2125 2126
	ibuf_contract_for_n_pages(TRUE, 5);

unknown's avatar
unknown committed
2127
	srv_main_thread_op_info = "flushing log";
unknown's avatar
unknown committed
2128
	log_buffer_flush_to_disk();
2129 2130 2131 2132

	/* We run a full purge every 10 seconds, even if the server
	were active */
	
2133 2134
	n_pages_purged = 1;

unknown's avatar
unknown committed
2135 2136
	last_flush_time = time(NULL);

2137
	while (n_pages_purged) {
unknown's avatar
unknown committed
2138

unknown's avatar
Merge  
unknown committed
2139 2140 2141 2142 2143
		if (srv_fast_shutdown && srv_shutdown_state > 0) {

			goto background_loop;
		}

unknown's avatar
unknown committed
2144
		srv_main_thread_op_info = "purging";
2145
		n_pages_purged = trx_purge();
2146

unknown's avatar
unknown committed
2147 2148 2149
		current_time = time(NULL);

		if (difftime(current_time, last_flush_time) > 1) {
unknown's avatar
unknown committed
2150
			srv_main_thread_op_info = "flushing log";
2151

unknown's avatar
unknown committed
2152
		        log_buffer_flush_to_disk();
unknown's avatar
unknown committed
2153 2154
			last_flush_time = current_time;
		}
2155
	}
unknown's avatar
unknown committed
2156
	
unknown's avatar
unknown committed
2157
	srv_main_thread_op_info = "flushing buffer pool pages";
2158

2159
	/* Flush a few oldest pages to make a new checkpoint younger */
unknown's avatar
unknown committed
2160

2161
	if (buf_get_modified_ratio_pct() > 70) {
unknown's avatar
unknown committed
2162

2163 2164 2165
		/* If there are lots of modified pages in the buffer pool
		(> 70 %), we assume we can afford reserving the disk(s) for
		the time it requires to flush 100 pages */
unknown's avatar
unknown committed
2166

unknown's avatar
unknown committed
2167 2168 2169
	        n_pages_flushed = buf_flush_batch(BUF_FLUSH_LIST, 100,
							ut_dulint_max);
	} else {
2170 2171 2172
	        /* Otherwise, we only flush a small number of pages so that
		we do not unnecessarily use much disk i/o capacity from
		other work */
unknown's avatar
unknown committed
2173

unknown's avatar
unknown committed
2174 2175 2176
	        n_pages_flushed = buf_flush_batch(BUF_FLUSH_LIST, 10,
							ut_dulint_max);
	}
unknown's avatar
unknown committed
2177

unknown's avatar
unknown committed
2178
	srv_main_thread_op_info = "making checkpoint";
unknown's avatar
unknown committed
2179 2180 2181 2182

	/* Make a new checkpoint about once in 10 seconds */

	log_checkpoint(TRUE, FALSE);
2183

unknown's avatar
unknown committed
2184
	srv_main_thread_op_info = "reserving kernel mutex";
2185

2186
	mutex_enter(&kernel_mutex);
2187 2188 2189 2190
	
	/* ---- When there is database activity, we jump from here back to
	the start of loop */

2191 2192 2193 2194
	if (srv_activity_count != old_activity_count) {
		mutex_exit(&kernel_mutex);
		goto loop;
	}
2195
	
2196 2197
	mutex_exit(&kernel_mutex);

2198 2199 2200 2201 2202
	/* If the database is quiet, we enter the background loop */

	/*****************************************************************/
background_loop:
	/* ---- In this loop we run background operations when the server
2203 2204
	is quiet from user activity. Also in the case of a shutdown, we
	loop here, flushing the buffer pool to the data files. */
2205

2206 2207 2208
	/* The server has been quiet for a while: start running background
	operations */
		
unknown's avatar
unknown committed
2209
	srv_main_thread_op_info = "doing background drop tables";
2210 2211 2212

	n_tables_to_drop = row_drop_tables_for_mysql_in_background();

2213 2214 2215 2216 2217 2218 2219 2220 2221
	if (n_tables_to_drop > 0) {
	        /* Do not monopolize the CPU even if there are tables waiting
		in the background drop queue. (It is essentially a bug if
		MySQL tries to drop a table while there are still open handles
		to it and we had to put it to the background drop queue.) */

		os_thread_sleep(100000);
	}
 
unknown's avatar
unknown committed
2222
	srv_main_thread_op_info = "purging";
2223

unknown's avatar
unknown committed
2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235
	/* Run a full purge */
	
	n_pages_purged = 1;

	last_flush_time = time(NULL);

	while (n_pages_purged) {
		if (srv_fast_shutdown && srv_shutdown_state > 0) {

			break;
		}

unknown's avatar
unknown committed
2236
		srv_main_thread_op_info = "purging";
unknown's avatar
unknown committed
2237 2238 2239 2240 2241
		n_pages_purged = trx_purge();

		current_time = time(NULL);

		if (difftime(current_time, last_flush_time) > 1) {
unknown's avatar
unknown committed
2242
			srv_main_thread_op_info = "flushing log";
unknown's avatar
unknown committed
2243 2244 2245 2246

		        log_buffer_flush_to_disk();
			last_flush_time = current_time;
		}
unknown's avatar
unknown committed
2247
	}
2248

unknown's avatar
unknown committed
2249
	srv_main_thread_op_info = "reserving kernel mutex";
2250

2251 2252 2253 2254 2255 2256 2257
	mutex_enter(&kernel_mutex);
	if (srv_activity_count != old_activity_count) {
		mutex_exit(&kernel_mutex);
		goto loop;
	}
	mutex_exit(&kernel_mutex);

unknown's avatar
unknown committed
2258
	srv_main_thread_op_info = "doing insert buffer merge";
unknown's avatar
unknown committed
2259 2260 2261 2262 2263 2264

	if (srv_fast_shutdown && srv_shutdown_state > 0) {
	        n_bytes_merged = 0;
	} else {
	        n_bytes_merged = ibuf_contract_for_n_pages(TRUE, 20);
	}
2265

unknown's avatar
unknown committed
2266
	srv_main_thread_op_info = "reserving kernel mutex";
2267

2268 2269 2270 2271 2272 2273 2274
	mutex_enter(&kernel_mutex);
	if (srv_activity_count != old_activity_count) {
		mutex_exit(&kernel_mutex);
		goto loop;
	}
	mutex_exit(&kernel_mutex);
	
2275
flush_loop:
unknown's avatar
unknown committed
2276
	srv_main_thread_op_info = "flushing buffer pool pages";
2277 2278 2279 2280 2281 2282 2283 2284 2285 2286

	if (!srv_very_fast_shutdown) {
		n_pages_flushed =
			buf_flush_batch(BUF_FLUSH_LIST, 100, ut_dulint_max);
	} else {
		/* In a 'very fast' shutdown we do not flush the buffer pool
		to data files: we set n_pages_flushed to 0 artificially. */

		n_pages_flushed = 0;
	}
2287

unknown's avatar
unknown committed
2288
	srv_main_thread_op_info = "reserving kernel mutex";
2289

2290 2291 2292 2293 2294 2295 2296
	mutex_enter(&kernel_mutex);
	if (srv_activity_count != old_activity_count) {
		mutex_exit(&kernel_mutex);
		goto loop;
	}
	mutex_exit(&kernel_mutex);
	
unknown's avatar
unknown committed
2297
	srv_main_thread_op_info = "waiting for buffer pool flush to end";
2298 2299
	buf_flush_wait_batch_end(BUF_FLUSH_LIST);

unknown's avatar
unknown committed
2300
	srv_main_thread_op_info = "flushing log";
unknown's avatar
unknown committed
2301 2302 2303

	log_buffer_flush_to_disk();

unknown's avatar
unknown committed
2304
	srv_main_thread_op_info = "making checkpoint";
2305

2306 2307
	log_checkpoint(TRUE, FALSE);

2308 2309 2310 2311 2312 2313 2314 2315
	if (buf_get_modified_ratio_pct() > srv_max_buf_pool_modified_pct) {

		/* Try to keep the number of modified pages in the
		buffer pool under the limit wished by the user */
			
		goto flush_loop;
	}

unknown's avatar
unknown committed
2316
	srv_main_thread_op_info = "reserving kernel mutex";
2317

2318 2319 2320 2321 2322 2323
	mutex_enter(&kernel_mutex);
	if (srv_activity_count != old_activity_count) {
		mutex_exit(&kernel_mutex);
		goto loop;
	}
	mutex_exit(&kernel_mutex);
unknown's avatar
unknown committed
2324
/*
unknown's avatar
unknown committed
2325
	srv_main_thread_op_info = "archiving log (if log archive is on)";
2326 2327
	
	log_archive_do(FALSE, &n_bytes_archived);
unknown's avatar
unknown committed
2328 2329
*/
	n_bytes_archived = 0;
2330

2331 2332
	/* Keep looping in the background loop if still work to do */

unknown's avatar
Merge  
unknown committed
2333
	if (srv_fast_shutdown && srv_shutdown_state > 0) {
unknown's avatar
unknown committed
2334 2335
		if (n_tables_to_drop + n_pages_flushed
				+ n_bytes_archived != 0) {
unknown's avatar
Merge  
unknown committed
2336

2337 2338
			/* If we are doing a fast shutdown (= the default)
			we do not do purge or insert buffer merge. But we
2339 2340 2341 2342
			flush the buffer pool completely to disk.
			In a 'very fast' shutdown we do not flush the buffer
			pool to data files: we have set n_pages_flushed to
			0 artificially. */
2343

unknown's avatar
Merge  
unknown committed
2344 2345
			goto background_loop;
		}
unknown's avatar
unknown committed
2346
	} else if (n_tables_to_drop +
2347
		   n_pages_purged + n_bytes_merged + n_pages_flushed
2348
						+ n_bytes_archived != 0) {
2349 2350 2351
		/* In a 'slow' shutdown we run purge and the insert buffer
		merge to completion */

2352 2353 2354 2355 2356 2357
		goto background_loop;
	}
		
	/* There is no work for background operations either: suspend
	master thread to wait for more server activity */
	
unknown's avatar
Merge  
unknown committed
2358
suspend_thread:
unknown's avatar
unknown committed
2359
	srv_main_thread_op_info = "suspending";
2360

2361 2362
	mutex_enter(&kernel_mutex);

unknown's avatar
unknown committed
2363 2364 2365 2366 2367 2368
	if (row_get_background_drop_list_len_low() > 0) {
		mutex_exit(&kernel_mutex);

		goto loop;
	}

2369 2370 2371 2372
	event = srv_suspend_thread();

	mutex_exit(&kernel_mutex);

unknown's avatar
unknown committed
2373
	srv_main_thread_op_info = "waiting for server activity";
2374

2375 2376
	os_event_wait(event);

unknown's avatar
unknown committed
2377 2378 2379 2380 2381 2382 2383
	if (srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS) {
	        /* This is only extra safety, the thread should exit
		already when the event wait ends */

	        os_thread_exit(NULL);
	}

2384 2385 2386
	/* When there is user activity, InnoDB will set the event and the main
	thread goes back to loop: */

2387 2388
	goto loop;

2389 2390 2391 2392 2393 2394 2395
	/* We count the number of threads in os_thread_exit(). A created
	thread should always use that to exit and not use return() to exit.
	The thread actually never comes here because it is exited in an
	os_event_wait(). */
	
	os_thread_exit(NULL);

2396
#ifndef __WIN__
2397
        return(NULL);				/* Not reached */
2398
#else
2399
	return(0);
2400
#endif
2401
}