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Commit 9c97dbab authored by Ingo Struewing's avatar Ingo Struewing
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Bug#17332 - changing key_buffer_size on a running server 

            can crash under load

Merge from 5.0, after backport from 5.1/5.4 to 5.0.
This makes the fixes for
Bug 44068 (RESTORE can disable the MyISAM Key Cache)
Bug 40944 (Backup: crash after myisampack)
available to 5.1.
parents fe3b6356 540b2dc0
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Showing with 96 additions and 52 deletions
mysys/mf_keycache.c
View file @ 9c97dbab
......@@ -13,7 +13,8 @@
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/*
/**
@file
These functions handle keyblock cacheing for ISAM and MyISAM tables.
One cache can handle many files.
......@@ -36,7 +37,9 @@
blocks_unused is the sum of never used blocks in the pool and of currently
free blocks. blocks_used is the number of blocks fetched from the pool and
as such gives the maximum number of in-use blocks at any time.
*/
/*
Key Cache Locking
=================
......@@ -368,8 +371,8 @@ static inline uint next_power(uint value)
*/
int init_key_cache(KEY_CACHE *keycache, uint key_cache_block_size,
size_t use_mem, uint division_limit,
uint age_threshold)
size_t use_mem, uint division_limit,
uint age_threshold)
{
ulong blocks, hash_links;
size_t length;
......@@ -560,8 +563,8 @@ int init_key_cache(KEY_CACHE *keycache, uint key_cache_block_size,
*/
int resize_key_cache(KEY_CACHE *keycache, uint key_cache_block_size,
size_t use_mem, uint division_limit,
uint age_threshold)
size_t use_mem, uint division_limit,
uint age_threshold)
{
int blocks;
DBUG_ENTER("resize_key_cache");
......@@ -760,6 +763,13 @@ void end_key_cache(KEY_CACHE *keycache, my_bool cleanup)
(ulong) keycache->global_cache_r_requests,
(ulong) keycache->global_cache_read));
/*
Reset these values to be able to detect a disabled key cache.
See Bug#44068 (RESTORE can disable the MyISAM Key Cache).
*/
keycache->blocks_used= 0;
keycache->blocks_unused= 0;
if (cleanup)
{
pthread_mutex_destroy(&keycache->cache_lock);
......@@ -1343,7 +1353,11 @@ static void unreg_request(KEY_CACHE *keycache,
DBUG_ASSERT(block->prev_changed && *block->prev_changed == block);
DBUG_ASSERT(!block->next_used);
DBUG_ASSERT(!block->prev_used);
if (! --block->requests)
/*
Unregister the request, but do not link erroneous blocks into the
LRU ring.
*/
if (!--block->requests && !(block->status & BLOCK_ERROR))
{
my_bool hot;
if (block->hits_left)
......@@ -1425,8 +1439,7 @@ static void wait_for_readers(KEY_CACHE *keycache,
#ifdef THREAD
struct st_my_thread_var *thread= my_thread_var;
DBUG_ASSERT(block->status & (BLOCK_READ | BLOCK_IN_USE));
DBUG_ASSERT(!(block->status & (BLOCK_ERROR | BLOCK_IN_FLUSH |
BLOCK_CHANGED)));
DBUG_ASSERT(!(block->status & (BLOCK_IN_FLUSH | BLOCK_CHANGED)));
DBUG_ASSERT(block->hash_link);
DBUG_ASSERT(block->hash_link->block == block);
/* Linked in file_blocks or changed_blocks hash. */
......@@ -2210,9 +2223,9 @@ static BLOCK_LINK *find_key_block(KEY_CACHE *keycache,
thread might change the block->hash_link value
*/
error= my_pwrite(block->hash_link->file,
block->buffer+block->offset,
block->buffer + block->offset,
block->length - block->offset,
block->hash_link->diskpos+ block->offset,
block->hash_link->diskpos + block->offset,
MYF(MY_NABP | MY_WAIT_IF_FULL));
keycache_pthread_mutex_lock(&keycache->cache_lock);
......@@ -2536,7 +2549,6 @@ uchar *key_cache_read(KEY_CACHE *keycache,
reg1 BLOCK_LINK *block;
uint read_length;
uint offset;
uint status;
int page_st;
/*
......@@ -2571,9 +2583,11 @@ uchar *key_cache_read(KEY_CACHE *keycache,
do
{
/* Cache could be disabled in a later iteration. */
if (!keycache->can_be_used)
goto no_key_cache;
{
KEYCACHE_DBUG_PRINT("key_cache_read", ("keycache cannot be used"));
goto no_key_cache;
}
/* Start reading at the beginning of the cache block. */
filepos-= offset;
/* Do not read beyond the end of the cache block. */
......@@ -2634,7 +2648,7 @@ uchar *key_cache_read(KEY_CACHE *keycache,
}
/* block status may have added BLOCK_ERROR in the above 'if'. */
if (!((status= block->status) & BLOCK_ERROR))
if (!(block->status & BLOCK_ERROR))
{
#ifndef THREAD
if (! return_buffer)
......@@ -2660,14 +2674,22 @@ uchar *key_cache_read(KEY_CACHE *keycache,
remove_reader(block);
/*
Link the block into the LRU ring if it's the last submitted
request for the block. This enables eviction for the block.
*/
unreg_request(keycache, block, 1);
/* Error injection for coverage testing. */
DBUG_EXECUTE_IF("key_cache_read_block_error",
block->status|= BLOCK_ERROR;);
if (status & BLOCK_ERROR)
/* Do not link erroneous blocks into the LRU ring, but free them. */
if (!(block->status & BLOCK_ERROR))
{
/*
Link the block into the LRU ring if it's the last submitted
request for the block. This enables eviction for the block.
*/
unreg_request(keycache, block, 1);
}
else
{
free_block(keycache, block);
error= 1;
break;
}
......@@ -2677,7 +2699,7 @@ uchar *key_cache_read(KEY_CACHE *keycache,
if (return_buffer)
DBUG_RETURN(block->buffer);
#endif
next_block:
next_block:
buff+= read_length;
filepos+= read_length+offset;
offset= 0;
......@@ -2685,6 +2707,7 @@ uchar *key_cache_read(KEY_CACHE *keycache,
} while ((length-= read_length));
goto end;
}
KEYCACHE_DBUG_PRINT("key_cache_read", ("keycache not initialized"));
no_key_cache:
/* Key cache is not used */
......@@ -2705,6 +2728,7 @@ uchar *key_cache_read(KEY_CACHE *keycache,
dec_counter_for_resize_op(keycache);
keycache_pthread_mutex_unlock(&keycache->cache_lock);
}
DBUG_PRINT("exit", ("error: %d", error ));
DBUG_RETURN(error ? (uchar*) 0 : start);
}
......@@ -2913,19 +2937,27 @@ int key_cache_insert(KEY_CACHE *keycache,
DBUG_ASSERT(block->status & (BLOCK_READ | BLOCK_IN_USE));
} /* end of if (!(block->status & BLOCK_ERROR)) */
remove_reader(block);
/*
Link the block into the LRU ring if it's the last submitted
request for the block. This enables eviction for the block.
*/
unreg_request(keycache, block, 1);
error= (block->status & BLOCK_ERROR);
/* Error injection for coverage testing. */
DBUG_EXECUTE_IF("key_cache_insert_block_error",
block->status|= BLOCK_ERROR; errno=EIO;);
if (error)
/* Do not link erroneous blocks into the LRU ring, but free them. */
if (!(block->status & BLOCK_ERROR))
{
/*
Link the block into the LRU ring if it's the last submitted
request for the block. This enables eviction for the block.
*/
unreg_request(keycache, block, 1);
}
else
{
free_block(keycache, block);
error= 1;
break;
}
buff+= read_length;
filepos+= read_length+offset;
......@@ -3176,7 +3208,7 @@ int key_cache_write(KEY_CACHE *keycache,
if (!dont_write)
{
/* Not used in the server. buff has been written to disk at start. */
/* Not used in the server. buff has been written to disk at start. */
if ((block->status & BLOCK_CHANGED) &&
(!offset && read_length >= keycache->key_cache_block_size))
link_to_file_list(keycache, block, block->hash_link->file, 1);
......@@ -3206,14 +3238,24 @@ int key_cache_write(KEY_CACHE *keycache,
*/
remove_reader(block);
/*
Link the block into the LRU ring if it's the last submitted
request for the block. This enables eviction for the block.
*/
unreg_request(keycache, block, 1);
/* Error injection for coverage testing. */
DBUG_EXECUTE_IF("key_cache_write_block_error",
block->status|= BLOCK_ERROR;);
if (block->status & BLOCK_ERROR)
/* Do not link erroneous blocks into the LRU ring, but free them. */
if (!(block->status & BLOCK_ERROR))
{
/*
Link the block into the LRU ring if it's the last submitted
request for the block. This enables eviction for the block.
*/
unreg_request(keycache, block, 1);
}
else
{
/* Pretend a "clean" block to avoid complications. */
block->status&= ~(BLOCK_CHANGED);
free_block(keycache, block);
error= 1;
break;
}
......@@ -3288,8 +3330,9 @@ static void free_block(KEY_CACHE *keycache, BLOCK_LINK *block)
{
KEYCACHE_THREAD_TRACE("free block");
KEYCACHE_DBUG_PRINT("free_block",
("block %u to be freed, hash_link %p",
BLOCK_NUMBER(block), block->hash_link));
("block %u to be freed, hash_link %p status: %u",
BLOCK_NUMBER(block), block->hash_link,
block->status));
/*
Assert that the block is not free already. And that it is in a clean
state. Note that the block might just be assigned to a hash_link and
......@@ -3371,10 +3414,14 @@ static void free_block(KEY_CACHE *keycache, BLOCK_LINK *block)
if (block->status & BLOCK_IN_EVICTION)
return;
/* Here the block must be in the LRU ring. Unlink it again. */
DBUG_ASSERT(block->next_used && block->prev_used &&
*block->prev_used == block);
unlink_block(keycache, block);
/* Error blocks are not put into the LRU ring. */
if (!(block->status & BLOCK_ERROR))
{
/* Here the block must be in the LRU ring. Unlink it again. */
DBUG_ASSERT(block->next_used && block->prev_used &&
*block->prev_used == block);
unlink_block(keycache, block);
}
if (block->temperature == BLOCK_WARM)
keycache->warm_blocks--;
block->temperature= BLOCK_COLD;
......@@ -3463,8 +3510,7 @@ static int flush_cached_blocks(KEY_CACHE *keycache,
(BLOCK_READ | BLOCK_IN_FLUSH | BLOCK_CHANGED | BLOCK_IN_USE));
block->status|= BLOCK_IN_FLUSHWRITE;
keycache_pthread_mutex_unlock(&keycache->cache_lock);
error= my_pwrite(file,
block->buffer+block->offset,
error= my_pwrite(file, block->buffer+block->offset,
block->length - block->offset,
block->hash_link->diskpos+ block->offset,
MYF(MY_NABP | MY_WAIT_IF_FULL));
......@@ -3491,7 +3537,6 @@ static int flush_cached_blocks(KEY_CACHE *keycache,
right queue anyway.
*/
link_to_file_list(keycache, block, file, 1);
}
block->status&= ~BLOCK_IN_FLUSH;
/*
......@@ -3527,7 +3572,7 @@ static int flush_cached_blocks(KEY_CACHE *keycache,
/*
flush all key blocks for a file to disk, but don't do any mutex locks.
Flush all key blocks for a file to disk, but don't do any mutex locks.
SYNOPSIS
flush_key_blocks_int()
......@@ -3560,8 +3605,8 @@ static int flush_key_blocks_int(KEY_CACHE *keycache,
file, keycache->blocks_used, keycache->blocks_changed));
#if !defined(DBUG_OFF) && defined(EXTRA_DEBUG)
DBUG_EXECUTE("check_keycache",
test_key_cache(keycache, "start of flush_key_blocks", 0););
DBUG_EXECUTE("check_keycache",
test_key_cache(keycache, "start of flush_key_blocks", 0););
#endif
cache= cache_buff;
......@@ -3692,7 +3737,6 @@ static int flush_key_blocks_int(KEY_CACHE *keycache,
{
/* It's a temporary file */
DBUG_ASSERT(!(block->status & BLOCK_REASSIGNED));
/*
free_block() must not be called with BLOCK_CHANGED. Note
that we must not change the BLOCK_CHANGED flag outside of
......@@ -4403,8 +4447,8 @@ static void keycache_debug_print(const char * fmt,...)
va_start(args,fmt);
if (keycache_debug_log)
{
VOID(vfprintf(keycache_debug_log, fmt, args));
VOID(fputc('\n',keycache_debug_log));
(void) vfprintf(keycache_debug_log, fmt, args);
(void) fputc('\n',keycache_debug_log);
}
va_end(args);
}
......
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