merge from 5.1 main

client/mysql.cc

@@ -15,11 +15,6 @@
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */
 
-#define COPYRIGHT_NOTICE "\
-Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.\n\
-This software comes with ABSOLUTELY NO WARRANTY. This is free software,\n\
-and you are welcome to modify and redistribute it under the GPL v2 license\n"
-
 /* mysql command tool
  * Commands compatible with mSQL by David J. Hughes
  *
@@ -120,6 +115,7 @@ extern "C" {
 #endif
 
 #include "completion_hash.h"
+#include <welcome_copyright_notice.h> // ORACLE_WELCOME_COPYRIGHT_NOTICE
 
 #define PROMPT_CHAR '\\'
 #define DEFAULT_DELIMITER ";"
@@ -1174,7 +1170,7 @@ int main(int argc,char *argv[])
 	  mysql_thread_id(&mysql), server_version_string(&mysql));
   put_info((char*) glob_buffer.ptr(),INFO_INFO);
 
-  put_info(COPYRIGHT_NOTICE, INFO_INFO);
+  put_info(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"), INFO_INFO);
 
 #ifdef HAVE_READLINE
   initialize_readline((char*) my_progname);
@@ -1593,7 +1589,7 @@ static void usage(int version)
 
   if (version)
     return;
-  printf("%s", COPYRIGHT_NOTICE);
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
   printf("Usage: %s [OPTIONS] [database]\n", my_progname);
   my_print_help(my_long_options);
   print_defaults("my", load_default_groups);

client/mysql_upgrade.c

 /*
-   Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2006, 2011, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -19,6 +19,8 @@
 #include <sslopt-vars.h>
 #include "../scripts/mysql_fix_privilege_tables_sql.c"
 
+#include <welcome_copyright_notice.h> /* ORACLE_WELCOME_COPYRIGHT_NOTICE */
+
 #define VER "1.1"
 
 #ifdef HAVE_SYS_WAIT_H
@@ -228,6 +230,7 @@ get_one_option(int optid, const struct my_option *opt,
   switch (optid) {
 
   case '?':
+    puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
     printf("%s  Ver %s Distrib %s, for %s (%s)\n",
            my_progname, VER, MYSQL_SERVER_VERSION, SYSTEM_TYPE, MACHINE_TYPE);
     puts("MySQL utility for upgrading databases to new MySQL versions.\n");

client/mysqladmin.cc

@@ -25,6 +25,7 @@
 #include <sys/stat.h>
 #include <mysql.h>
 #include <sql_common.h>
+#include <welcome_copyright_notice.h>           /* ORACLE_WELCOME_COPYRIGHT_NOTICE */
 
 #define ADMIN_VERSION "8.42"
 #define MAX_MYSQL_VAR 512
@@ -692,8 +693,7 @@ static int execute_commands(MYSQL *mysql,int argc, char **argv)
     case ADMIN_VER:
       new_line=1;
       print_version();
-      puts("Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.");
-      puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\nand you are welcome to modify and redistribute it under the GPL license\n");
+      puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
       printf("Server version\t\t%s\n", mysql_get_server_info(mysql));
       printf("Protocol version\t%d\n", mysql_get_proto_info(mysql));
       printf("Connection\t\t%s\n",mysql_get_host_info(mysql));
@@ -1072,8 +1072,7 @@ static void print_version(void)
 static void usage(void)
 {
   print_version();
-  puts("Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.");
-  puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\nand you are welcome to modify and redistribute it under the GPL license\n");
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
   puts("Administration program for the mysqld daemon.");
   printf("Usage: %s [OPTIONS] command command....\n", my_progname);
   my_print_help(my_long_options);

client/mysqlcheck.c

 /*
-   Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -15,8 +15,6 @@
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
 */
 
-/* By Jani Tolonen, 2001-04-20, MySQL Development Team */
-
 #define CHECK_VERSION "2.5.0"
 
 #include "client_priv.h"
@@ -24,6 +22,7 @@
 #include <mysql_version.h>
 #include <mysqld_error.h>
 #include <sslopt-vars.h>
+#include <welcome_copyright_notice.h> /* ORACLE_WELCOME_COPYRIGHT_NOTICE */
 
 /* Exit codes */
 
@@ -223,9 +222,7 @@ static void print_version(void)
 static void usage(void)
 {
   print_version();
-  puts("By Jani Tolonen, 2001-04-20, MySQL Development Team.\n");
-  puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\n");
-  puts("and you are welcome to modify and redistribute it under the GPL license.\n");
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
   puts("This program can be used to CHECK (-c, -m, -C), REPAIR (-r), ANALYZE (-a),");
   puts("or OPTIMIZE (-o) tables. Some of the options (like -e or -q) can be");
   puts("used at the same time. Not all options are supported by all storage engines.");

client/mysqldump.c

@@ -54,6 +54,8 @@
 #include "mysqld_error.h"
 #include "../sql/ha_ndbcluster_tables.h"
 
+#include <welcome_copyright_notice.h> /* ORACLE_WELCOME_COPYRIGHT_NOTICE */
+
 /* Exit codes */
 
 #define EX_USAGE 1
@@ -569,8 +571,7 @@ static void short_usage_sub(void)
 static void usage(void)
 {
   print_version();
-  puts("By Igor Romanenko, Monty, Jani & Sinisa.");
-  puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\nand you are welcome to modify and redistribute it under the GPL license.\n");
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
   puts("Dumping structure and contents of MySQL databases and tables.");
   short_usage_sub();
   print_defaults("my",load_default_groups);

client/mysqlimport.c

 /*
-   Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -18,14 +18,8 @@
 /*
 **	   mysqlimport.c  - Imports all given files
 **			    into a table(s).
-**
-**			   *************************
-**			   *			   *
-**			   * AUTHOR: Monty & Jani  *
-**			   * DATE:   June 24, 1997 *
-**			   *			   *
-**			   *************************
 */
+
 #define IMPORT_VERSION "3.7"
 
 #include "client_priv.h"
@@ -42,6 +36,8 @@ pthread_mutex_t counter_mutex;
 pthread_cond_t count_threshhold;
 #endif
 
+#include <welcome_copyright_notice.h>   /* ORACLE_WELCOME_COPYRIGHT_NOTICE */
+
 static void db_error_with_table(MYSQL *mysql, char *table);
 static void db_error(MYSQL *mysql);
 static char *field_escape(char *to,const char *from,uint length);
@@ -200,8 +196,7 @@ static void print_version(void)
 static void usage(void)
 {
   print_version();
-  puts("Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.");
-  puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\nand you are welcome to modify and redistribute it under the GPL license.\n");
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
   printf("\
 Loads tables from text files in various formats.  The base name of the\n\
 text file must be the name of the table that should be used.\n\

client/mysqlshow.c

 /*
-   Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+   Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -27,6 +27,7 @@
 #include <signal.h>
 #include <stdarg.h>
 #include <sslopt-vars.h>
+#include <welcome_copyright_notice.h>   /* ORACLE_WELCOME_COPYRIGHT_NOTICE */
 
 static char * host=0, *opt_password=0, *user=0;
 static my_bool opt_show_keys= 0, opt_compress= 0, opt_count=0, opt_status= 0;
@@ -255,8 +256,7 @@ static void print_version(void)
 static void usage(void)
 {
   print_version();
-  puts("Copyright 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.");
-  puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\nand you are welcome to modify and redistribute it under the GPL license.\n");
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011)"));
   puts("Shows the structure of a MySQL database (databases, tables, and columns).\n");
   printf("Usage: %s [OPTIONS] [database [table [column]]]\n",my_progname);
   puts("\n\

client/mysqltest.cc

@@ -24,13 +24,6 @@
   http://dev.mysql.com/doc/mysqltest/en/index.html
 
   Please keep the test framework tools identical in all versions!
-
-  Written by:
-  Sasha Pachev <sasha@mysql.com>
-  Matt Wagner  <matt@mysql.com>
-  Monty
-  Jani
-  Holyfoot
 */
 
 #define MTEST_VERSION "3.3"
@@ -53,6 +46,8 @@
 #include <signal.h>
 #include <my_stacktrace.h>
 
+#include <welcome_copyright_notice.h> // ORACLE_WELCOME_COPYRIGHT_NOTICE
+
 #ifdef __WIN__
 #include <crtdbg.h>
 #define SIGNAL_FMT "exception 0x%x"
@@ -6125,8 +6120,7 @@ void print_version(void)
 void usage()
 {
   print_version();
-  printf("MySQL AB, by Sasha, Matt, Monty & Jani\n");
-  printf("This software comes with ABSOLUTELY NO WARRANTY\n\n");
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
   printf("Runs a test against the mysql server and compares output with a results file.\n\n");
   printf("Usage: %s [OPTIONS] [database] < test_file\n", my_progname);
   my_print_help(my_long_options);

sql/gen_lex_hash.cc

-/* Copyright (c) 2000-2007 MySQL AB, 2009 Sun Microsystems, Inc.
-   Use is subject to license terms.
+/*
+   Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -89,6 +89,8 @@ So, we can read full search-structure as 32-bit word
 #include "mysql_version.h"
 #include "lex.h"
 
+#include <welcome_copyright_notice.h> /* ORACLE_WELCOME_COPYRIGHT_NOTICE */
+
 const char *default_dbug_option="d:t:o,/tmp/gen_lex_hash.trace";
 
 struct my_option my_long_options[] =
@@ -348,9 +350,7 @@ static void usage(int version)
 	 my_progname, MYSQL_SERVER_VERSION, SYSTEM_TYPE, MACHINE_TYPE);
   if (version)
     return;
-  puts("Copyright (C) 2001 MySQL AB, by VVA and Monty");
-  puts("This software comes with ABSOLUTELY NO WARRANTY. This is free software,\n\
-and you are welcome to modify and redistribute it under the GPL license\n");
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
   puts("This program generates a perfect hashing function for the sql_lex.cc");
   printf("Usage: %s [OPTIONS]\n\n", my_progname);
   my_print_help(my_long_options);
@@ -452,24 +452,9 @@ int main(int argc,char **argv)
   /* Broken up to indicate that it's not advice to you, gentle reader. */
   printf("/*\n\n  Do " "not " "edit " "this " "file " "directly!\n\n*/\n");
 
-  printf("\
-/* Copyright (C) 2000-2008 MySQL AB, 2008 Sun Microsystems, Inc.\n\
-\n\
-   This program is free software; you can redistribute it and/or modify\n\
-   it under the terms of the GNU General Public License as published by\n\
-   the Free Software Foundation; version 2 of the License.\n\
-\n\
-   This program is distributed in the hope that it will be useful,\n\
-   but WITHOUT ANY WARRANTY; without even the implied warranty of\n\
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n\
-   GNU General Public License for more details.\n\
-\n\
-   You should have received a copy of the GNU General Public License\n\
-   along with this program; see the file COPYING. If not, write to the\n\
-   Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston\n\
-   MA  02110-1301  USA. */\n\
-\n\
-");
+  puts("/*");
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
+  puts("*/");
 
   /* Broken up to indicate that it's not advice to you, gentle reader. */
   printf("/* Do " "not " "edit " "this " "file!  This is generated by "

sql/mysqld.cc

@@ -279,6 +279,8 @@ extern "C" sig_handler handle_segfault(int sig);
 
 /* Constants */
 
+#include <welcome_copyright_notice.h> // ORACLE_WELCOME_COPYRIGHT_NOTICE
+
 const char *show_comp_option_name[]= {"YES", "NO", "DISABLED"};
 /*
   WARNING: When adding new SQL modes don't forget to update the
@@ -7796,13 +7798,8 @@ static void usage(void)
   if (!default_collation_name)
     default_collation_name= (char*) default_charset_info->name;
   print_version();
-  puts("\
-Copyright (C) 2000-2008 MySQL AB, by Monty and others.\n\
-Copyright (C) 2008 Sun Microsystems, Inc.\n\
-This software comes with ABSOLUTELY NO WARRANTY. This is free software,\n\
-and you are welcome to modify and redistribute it under the GPL license\n\n\
-Starts the MySQL database server.\n");
-
+  puts(ORACLE_WELCOME_COPYRIGHT_NOTICE("2000, 2011"));
+  puts("Starts the MySQL database server.\n");
   printf("Usage: %s [OPTIONS]\n", my_progname);
   if (!opt_verbose)
     puts("\nFor more help options (several pages), use mysqld --verbose --help.");

sql/protocol.cc

@@ -857,8 +857,8 @@ bool Protocol_text::store(const char *from, size_t length,
 {
   CHARSET_INFO *tocs= this->thd->variables.character_set_results;
 #ifndef DBUG_OFF
-  DBUG_PRINT("info", ("Protocol_text::store field %u (%u): %s", field_pos,
-                      field_count, (length == 0? "" : from)));
+  DBUG_PRINT("info", ("Protocol_text::store field %u (%u): %.*s", field_pos,
+                      field_count, (int) length, (length == 0 ? "" : from)));
   DBUG_ASSERT(field_pos < field_count);
   DBUG_ASSERT(field_types == 0 ||
 	      field_types[field_pos] == MYSQL_TYPE_DECIMAL ||

storage/innodb_plugin/ChangeLog

+2011-07-19	The InnoDB Team
+
+	* buf/buf0buf.c, buf/buf0rea.c, handler/ha_innodb.cc,
+	include/buf0buf.h, include/buf0buf.ic, include/srv0srv.h,
+	srv/srv0srv.c:
+	Fix bug#Bug 12356373 by reintroducing random readahead
+
 2011-06-30	The InnoDB Team
 
 	* row/row0row.c:

storage/innodb_plugin/buf/buf0buf.c

@@ -3590,12 +3590,16 @@ buf_print_io(
 
 	/* Statistics about read ahead algorithm */
 	fprintf(file, "Pages read ahead %.2f/s,"
-		" evicted without access %.2f/s\n",
+		" evicted without access %.2f/s,"
+		" Random read ahead %.2f/s\n",
 		(buf_pool->stat.n_ra_pages_read
 		- buf_pool->old_stat.n_ra_pages_read)
 		/ time_elapsed,
 		(buf_pool->stat.n_ra_pages_evicted
 		- buf_pool->old_stat.n_ra_pages_evicted)
+		/ time_elapsed,
+		(buf_pool->stat.n_ra_pages_read_rnd
+		- buf_pool->old_stat.n_ra_pages_read_rnd)
 		/ time_elapsed);
 
 	/* Print some values to help us with visualizing what is

storage/innodb_plugin/buf/buf0rea.c

@@ -38,6 +38,14 @@ Created 11/5/1995 Heikki Tuuri
 #include "srv0start.h"
 #include "srv0srv.h"
 
+/** The size in blocks of the area where the random read-ahead algorithm counts
+the accessed pages when deciding whether to read-ahead */
+#define	BUF_READ_AHEAD_RANDOM_AREA	BUF_READ_AHEAD_AREA
+
+/** There must be at least this many pages in buf_pool in the area to start
+a random read-ahead */
+#define BUF_READ_AHEAD_RANDOM_THRESHOLD	(5 + BUF_READ_AHEAD_RANDOM_AREA / 8)
+
 /** The linear read-ahead area size */
 #define	BUF_READ_AHEAD_LINEAR_AREA	BUF_READ_AHEAD_AREA
 
@@ -157,6 +165,165 @@ buf_read_page_low(
 	return(1);
 }
 
+/********************************************************************//**
+Applies a random read-ahead in buf_pool if there are at least a threshold
+value of accessed pages from the random read-ahead area. Does not read any
+page, not even the one at the position (space, offset), if the read-ahead
+mechanism is not activated. NOTE 1: the calling thread may own latches on
+pages: to avoid deadlocks this function must be written such that it cannot
+end up waiting for these latches! NOTE 2: the calling thread must want
+access to the page given: this rule is set to prevent unintended read-aheads
+performed by ibuf routines, a situation which could result in a deadlock if
+the OS does not support asynchronous i/o.
+@return number of page read requests issued; NOTE that if we read ibuf
+pages, it may happen that the page at the given page number does not
+get read even if we return a positive value! */
+static
+ulint
+buf_read_ahead_random(
+/*==================*/
+	ulint	space,	/*!< in: space id */
+	ulint	zip_size,/*!< in: compressed page size in bytes, or 0 */
+	ulint	offset)	/*!< in: page number of a page which the current thread
+			wants to access */
+{
+	ib_int64_t	tablespace_version;
+	ulint		recent_blocks	= 0;
+	ulint		count;
+	ulint		ibuf_mode;
+	ulint		low, high;
+	ulint		err;
+	ulint		i;
+	ulint		buf_read_ahead_random_area;
+
+	if (!srv_random_read_ahead) {
+		/* Disabled by user */
+		return(0);
+	}
+
+	if (srv_startup_is_before_trx_rollback_phase) {
+		/* No read-ahead to avoid thread deadlocks */
+		return(0);
+	}
+
+	if (ibuf_bitmap_page(zip_size, offset)
+	    || trx_sys_hdr_page(space, offset)) {
+
+		/* If it is an ibuf bitmap page or trx sys hdr, we do
+		no read-ahead, as that could break the ibuf page access
+		order */
+
+		return(0);
+	}
+
+	/* Remember the tablespace version before we ask the tablespace size
+	below: if DISCARD + IMPORT changes the actual .ibd file meanwhile, we
+	do not try to read outside the bounds of the tablespace! */
+
+	tablespace_version = fil_space_get_version(space);
+
+	buf_read_ahead_random_area = BUF_READ_AHEAD_RANDOM_AREA;
+
+	low  = (offset / buf_read_ahead_random_area)
+		* buf_read_ahead_random_area;
+	high = (offset / buf_read_ahead_random_area + 1)
+		* buf_read_ahead_random_area;
+	if (high > fil_space_get_size(space)) {
+
+		high = fil_space_get_size(space);
+	}
+
+	buf_pool_mutex_enter();
+
+	if (buf_pool->n_pend_reads
+	    > buf_pool->curr_size / BUF_READ_AHEAD_PEND_LIMIT) {
+		buf_pool_mutex_exit();
+
+		return(0);
+	}
+
+	/* Count how many blocks in the area have been recently accessed,
+	that is, reside near the start of the LRU list. */
+
+	for (i = low; i < high; i++) {
+		const buf_page_t*	bpage = buf_page_hash_get(space, i);
+
+		if (bpage
+		    && buf_page_is_accessed(bpage)
+		    && buf_page_peek_if_young(bpage)) {
+
+			recent_blocks++;
+
+			if (recent_blocks >= BUF_READ_AHEAD_RANDOM_THRESHOLD) {
+
+				buf_pool_mutex_exit();
+				goto read_ahead;
+			}
+		}
+	}
+
+	buf_pool_mutex_exit();
+	/* Do nothing */
+	return(0);
+
+read_ahead:
+	/* Read all the suitable blocks within the area */
+
+	if (ibuf_inside()) {
+		ibuf_mode = BUF_READ_IBUF_PAGES_ONLY;
+	} else {
+		ibuf_mode = BUF_READ_ANY_PAGE;
+	}
+
+	count = 0;
+
+	for (i = low; i < high; i++) {
+		/* It is only sensible to do read-ahead in the non-sync aio
+		mode: hence FALSE as the first parameter */
+
+		if (!ibuf_bitmap_page(zip_size, i)) {
+			count += buf_read_page_low(
+				&err, FALSE,
+				ibuf_mode | OS_AIO_SIMULATED_WAKE_LATER,
+				space, zip_size, FALSE,
+				tablespace_version, i);
+			if (err == DB_TABLESPACE_DELETED) {
+				ut_print_timestamp(stderr);
+				fprintf(stderr,
+					"  InnoDB: Warning: in random"
+					" readahead trying to access\n"
+					"InnoDB: tablespace %lu page %lu,\n"
+					"InnoDB: but the tablespace does not"
+					" exist or is just being dropped.\n",
+					(ulong) space, (ulong) i);
+			}
+		}
+	}
+
+	/* In simulated aio we wake the aio handler threads only after
+	queuing all aio requests, in native aio the following call does
+	nothing: */
+
+	os_aio_simulated_wake_handler_threads();
+
+#ifdef UNIV_DEBUG
+	if (buf_debug_prints && (count > 0)) {
+		fprintf(stderr,
+			"Random read-ahead space %lu offset %lu pages %lu\n",
+			(ulong) space, (ulong) offset,
+			(ulong) count);
+	}
+#endif /* UNIV_DEBUG */
+
+	/* Read ahead is considered one I/O operation for the purpose of
+	LRU policy decision. */
+	buf_LRU_stat_inc_io();
+
+	buf_pool->stat.n_ra_pages_read_rnd += count;
+	return(count);
+}
+
+
 /********************************************************************//**
 High-level function which reads a page asynchronously from a file to the
 buffer buf_pool if it is not already there. Sets the io_fix flag and sets
@@ -175,6 +342,9 @@ buf_read_page(
 	ulint		count;
 	ulint		err;
 
+	count = buf_read_ahead_random(space, zip_size, offset);
+	srv_buf_pool_reads += count;
+
 	tablespace_version = fil_space_get_version(space);
 
 	/* We do the i/o in the synchronous aio mode to save thread

storage/innodb_plugin/handler/ha_innodb.cc

@@ -501,6 +501,8 @@ static SHOW_VAR innodb_status_variables[]= {
   (char*) &export_vars.innodb_buffer_pool_pages_misc,	  SHOW_LONG},
   {"buffer_pool_pages_total",
   (char*) &export_vars.innodb_buffer_pool_pages_total,	  SHOW_LONG},
+  {"buffer_pool_read_ahead_rnd",
+  (char*) &export_vars.innodb_buffer_pool_read_ahead_rnd, SHOW_LONG},
   {"buffer_pool_read_ahead",
   (char*) &export_vars.innodb_buffer_pool_read_ahead,	  SHOW_LONG},
   {"buffer_pool_read_ahead_evicted",
@@ -11027,6 +11029,11 @@ static MYSQL_SYSVAR_UINT(change_buffering_debug, ibuf_debug,
   NULL, NULL, 0, 0, 1, 0);
 #endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
 
+static MYSQL_SYSVAR_BOOL(random_read_ahead, srv_random_read_ahead,
+  PLUGIN_VAR_NOCMDARG,
+  "Whether to use read ahead for random access within an extent.",
+  NULL, NULL, FALSE);
+
 static MYSQL_SYSVAR_ULONG(read_ahead_threshold, srv_read_ahead_threshold,
   PLUGIN_VAR_RQCMDARG,
   "Number of pages that must be accessed sequentially for InnoDB to "
@@ -11091,6 +11098,7 @@ static struct st_mysql_sys_var* innobase_system_variables[]= {
 #if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
   MYSQL_SYSVAR(change_buffering_debug),
 #endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
+  MYSQL_SYSVAR(random_read_ahead),
   MYSQL_SYSVAR(read_ahead_threshold),
   MYSQL_SYSVAR(io_capacity),
   NULL

storage/innodb_plugin/include/buf0buf.h

@@ -427,6 +427,18 @@ buf_block_get_freed_page_clock(
 	__attribute__((pure));
 
 /********************************************************************//**
+Tells if a block is still close enough to the MRU end of the LRU list
+meaning that it is not in danger of getting evicted and also implying
+that it has been accessed recently.
+Note that this is for heuristics only and does not reserve buffer pool
+mutex.
+@return	TRUE if block is close to MRU end of LRU */
+UNIV_INLINE
+ibool
+buf_page_peek_if_young(
+/*===================*/
+	const buf_page_t*	bpage);	/*!< in: block */
+/********************************************************************//**
 Recommends a move of a block to the start of the LRU list if there is danger
 of dropping from the buffer pool. NOTE: does not reserve the buffer pool
 mutex.
@@ -1334,6 +1346,8 @@ struct buf_pool_stat_struct{
 	ulint	n_pages_written;/*!< number write operations */
 	ulint	n_pages_created;/*!< number of pages created
 				in the pool with no read */
+	ulint	n_ra_pages_read_rnd;/*!< number of pages read in
+				as part of random read ahead */
 	ulint	n_ra_pages_read;/*!< number of pages read in
 				as part of read ahead */
 	ulint	n_ra_pages_evicted;/*!< number of read ahead

storage/innodb_plugin/include/buf0buf.ic

@@ -61,6 +61,27 @@ buf_block_get_freed_page_clock(
 	return(buf_page_get_freed_page_clock(&block->page));
 }
 
+/********************************************************************//**
+Tells if a block is still close enough to the MRU end of the LRU list
+meaning that it is not in danger of getting evicted and also implying
+that it has been accessed recently.
+Note that this is for heuristics only and does not reserve buffer pool
+mutex.
+@return	TRUE if block is close to MRU end of LRU */
+UNIV_INLINE
+ibool
+buf_page_peek_if_young(
+/*===================*/
+	const buf_page_t*	bpage)	/*!< in: block */
+{
+	/* FIXME: bpage->freed_page_clock is 31 bits */
+	return((buf_pool->freed_page_clock & ((1UL << 31) - 1))
+	       < ((ulint) bpage->freed_page_clock
+		  + (buf_pool->curr_size
+		     * (BUF_LRU_OLD_RATIO_DIV - buf_LRU_old_ratio)
+		     / (BUF_LRU_OLD_RATIO_DIV * 4))));
+}
+
 /********************************************************************//**
 Recommends a move of a block to the start of the LRU list if there is danger
 of dropping from the buffer pool. NOTE: does not reserve the buffer pool
@@ -89,12 +110,7 @@ buf_page_peek_if_too_old(
 		buf_pool->stat.n_pages_not_made_young++;
 		return(FALSE);
 	} else {
-		/* FIXME: bpage->freed_page_clock is 31 bits */
-		return((buf_pool->freed_page_clock & ((1UL << 31) - 1))
-		       > ((ulint) bpage->freed_page_clock
-			  + (buf_pool->curr_size
-			     * (BUF_LRU_OLD_RATIO_DIV - buf_LRU_old_ratio)
-			     / (BUF_LRU_OLD_RATIO_DIV * 4))));
+		return(!buf_page_peek_if_young(bpage));
 	}
 }
 

storage/innodb_plugin/include/srv0srv.h

@@ -143,6 +143,7 @@ extern ulint	srv_mem_pool_size;
 extern ulint	srv_lock_table_size;
 
 extern ulint	srv_n_file_io_threads;
+extern my_bool	srv_random_read_ahead;
 extern ulong	srv_read_ahead_threshold;
 extern ulint	srv_n_read_io_threads;
 extern ulint	srv_n_write_io_threads;
@@ -618,6 +619,7 @@ struct export_var_struct{
 	ulint innodb_buffer_pool_wait_free;	/*!< srv_buf_pool_wait_free */
 	ulint innodb_buffer_pool_pages_flushed;	/*!< srv_buf_pool_flushed */
 	ulint innodb_buffer_pool_write_requests;/*!< srv_buf_pool_write_requests */
+	ulint innodb_buffer_pool_read_ahead_rnd;/*!< srv_read_ahead_rnd */
 	ulint innodb_buffer_pool_read_ahead;	/*!< srv_read_ahead */
 	ulint innodb_buffer_pool_read_ahead_evicted;/*!< srv_read_ahead evicted*/
 	ulint innodb_dblwr_pages_written;	/*!< srv_dblwr_pages_written */

storage/innodb_plugin/srv/srv0srv.c

@@ -203,6 +203,8 @@ UNIV_INTERN ulint	srv_n_file_io_threads	= ULINT_MAX;
 UNIV_INTERN ulint	srv_n_read_io_threads	= ULINT_MAX;
 UNIV_INTERN ulint	srv_n_write_io_threads	= ULINT_MAX;
 
+/* Switch to enable random read ahead. */
+UNIV_INTERN my_bool	srv_random_read_ahead	= FALSE;
 /* User settable value of the number of pages that must be present
 in the buffer cache and accessed sequentially for InnoDB to trigger a
 readahead request. */
@@ -1906,6 +1908,8 @@ srv_export_innodb_status(void)
 	export_vars.innodb_buffer_pool_wait_free = srv_buf_pool_wait_free;
 	export_vars.innodb_buffer_pool_pages_flushed = srv_buf_pool_flushed;
 	export_vars.innodb_buffer_pool_reads = srv_buf_pool_reads;
+	export_vars.innodb_buffer_pool_read_ahead_rnd
+		= buf_pool->stat.n_ra_pages_read_rnd;
 	export_vars.innodb_buffer_pool_read_ahead
 		= buf_pool->stat.n_ra_pages_read;
 	export_vars.innodb_buffer_pool_read_ahead_evicted