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Applying InnoDB snashot 5.1-ss5024,part 3. Fixes BUG#42101

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BUG#42101 - Race condition in innodb_commit_concurrency

Detailed revision comments:

r4994 | marko | 2009-05-14 15:04:55 +0300 (Thu, 14 May 2009) | 18 lines
branches/5.1: Prevent a race condition in innobase_commit() by ensuring
that innodb_commit_concurrency>0 remains constant at run time. (Bug #42101)

srv_commit_concurrency: Make this a static variable in ha_innodb.cc.

innobase_commit_concurrency_validate(): Check that innodb_commit_concurrency
is not changed from or to 0 at run time.  This is needed, because
innobase_commit() assumes that innodb_commit_concurrency>0 remains constant.
Without this limitation, the checks for innodb_commit_concurrency>0
in innobase_commit() should be removed and that function would have to
acquire and release commit_cond_m at least twice per invocation.
Normally, innodb_commit_concurrency=0, and introducing the mutex operations
would mean significant overhead.

innodb_bug42101.test, innodb_bug42101-nonzero.test: Test cases.

rb://123 approved by Heikki Tuuri
This commit is contained in:
Satya B 2009-05-19 13:50:28 +05:30
parent 65eac15004
commit 07b9358860
8 changed files with 115 additions and 7 deletions
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22
mysql-test/r/innodb_bug42101-nonzero.result Normal file
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@ -0,0 +1,22 @@
set global innodb_commit_concurrency=0;
ERROR HY000: Incorrect arguments to SET
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
1
set global innodb_commit_concurrency=1;
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
1
set global innodb_commit_concurrency=42;
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
42
set global innodb_commit_concurrency=0;
ERROR HY000: Incorrect arguments to SET
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
42
set global innodb_commit_concurrency=1;
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
1

18
mysql-test/r/innodb_bug42101.result Normal file
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@ -0,0 +1,18 @@
set global innodb_commit_concurrency=0;
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
0
set global innodb_commit_concurrency=1;
ERROR HY000: Incorrect arguments to SET
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
0
set global innodb_commit_concurrency=42;
ERROR HY000: Incorrect arguments to SET
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
0
set global innodb_commit_concurrency=0;
select @@innodb_commit_concurrency;
@@innodb_commit_concurrency
0

1
mysql-test/t/innodb_bug42101-nonzero-master.opt Normal file
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@ -0,0 +1 @@
--innodb_commit_concurrency=1

19
mysql-test/t/innodb_bug42101-nonzero.test Normal file
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@ -0,0 +1,19 @@
#
# Bug#42101 Race condition in innodb_commit_concurrency
# http://bugs.mysql.com/42101
#
-- source include/have_innodb.inc
--error ER_WRONG_ARGUMENTS
set global innodb_commit_concurrency=0;
select @@innodb_commit_concurrency;
set global innodb_commit_concurrency=1;
select @@innodb_commit_concurrency;
set global innodb_commit_concurrency=42;
select @@innodb_commit_concurrency;
--error ER_WRONG_ARGUMENTS
set global innodb_commit_concurrency=0;
select @@innodb_commit_concurrency;
set global innodb_commit_concurrency=1;
select @@innodb_commit_concurrency;

17
mysql-test/t/innodb_bug42101.test Normal file
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@ -0,0 +1,17 @@
#
# Bug#42101 Race condition in innodb_commit_concurrency
# http://bugs.mysql.com/42101
#
-- source include/have_innodb.inc
set global innodb_commit_concurrency=0;
select @@innodb_commit_concurrency;
--error ER_WRONG_ARGUMENTS
set global innodb_commit_concurrency=1;
select @@innodb_commit_concurrency;
--error ER_WRONG_ARGUMENTS
set global innodb_commit_concurrency=42;
select @@innodb_commit_concurrency;
set global innodb_commit_concurrency=0;
select @@innodb_commit_concurrency;

43
storage/innobase/handler/ha_innodb.cc
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@ -101,6 +101,7 @@ static long innobase_mirrored_log_groups, innobase_log_files_in_group,
innobase_additional_mem_pool_size, innobase_file_io_threads,
innobase_lock_wait_timeout, innobase_force_recovery,
innobase_open_files, innobase_autoinc_lock_mode;
static ulong innobase_commit_concurrency = 0;
static long long innobase_buffer_pool_size, innobase_log_file_size;
@ -165,6 +166,38 @@ static handler *innobase_create_handler(handlerton *hton,
static const char innobase_hton_name[]= "InnoDB";
/*****************************************************************
Check for a valid value of innobase_commit_concurrency. */
static
int
innobase_commit_concurrency_validate(
/*=================================*/
/* out: 0 for valid
innodb_commit_concurrency */
THD* thd, /* in: thread handle */
struct st_mysql_sys_var* var, /* in: pointer to system
variable */
void* save, /* out: immediate result
for update function */
struct st_mysql_value* value) /* in: incoming string */
{
long long intbuf;
ulong commit_concurrency;
DBUG_ENTER("innobase_commit_concurrency_validate");
if (value->val_int(value, &intbuf)) {
/* The value is NULL. That is invalid. */
DBUG_RETURN(1);
}
*reinterpret_cast<ulong*>(save) = commit_concurrency
= static_cast<ulong>(intbuf);
/* Allow the value to be updated, as long as it remains zero
or nonzero. */
DBUG_RETURN(!(!commit_concurrency == !innobase_commit_concurrency));
}
static MYSQL_THDVAR_BOOL(support_xa, PLUGIN_VAR_OPCMDARG,
"Enable InnoDB support for the XA two-phase commit",
@ -1951,11 +1984,11 @@ innobase_commit(
Note, the position is current because of
prepare_commit_mutex */
retry:
if (srv_commit_concurrency > 0) {
if (innobase_commit_concurrency > 0) {
pthread_mutex_lock(&commit_cond_m);
commit_threads++;
if (commit_threads > srv_commit_concurrency) {
if (commit_threads > innobase_commit_concurrency) {
commit_threads--;
pthread_cond_wait(&commit_cond,
&commit_cond_m);
@ -1972,7 +2005,7 @@ retry:
innobase_commit_low(trx);
if (srv_commit_concurrency > 0) {
if (innobase_commit_concurrency > 0) {
pthread_mutex_lock(&commit_cond_m);
commit_threads--;
pthread_cond_signal(&commit_cond);
@ -8289,10 +8322,10 @@ static MYSQL_SYSVAR_LONGLONG(buffer_pool_size, innobase_buffer_pool_size,
"The size of the memory buffer InnoDB uses to cache data and indexes of its tables.",
NULL, NULL, 8*1024*1024L, 1024*1024L, LONGLONG_MAX, 1024*1024L);
static MYSQL_SYSVAR_ULONG(commit_concurrency, srv_commit_concurrency,
static MYSQL_SYSVAR_ULONG(commit_concurrency, innobase_commit_concurrency,
PLUGIN_VAR_RQCMDARG,
"Helps in performance tuning in heavily concurrent environments.",
NULL, NULL, 0, 0, 1000, 0);
innobase_commit_concurrency_validate, NULL, 0, 0, 1000, 0);
static MYSQL_SYSVAR_ULONG(concurrency_tickets, srv_n_free_tickets_to_enter,
PLUGIN_VAR_RQCMDARG,

1
storage/innobase/include/srv0srv.h
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@ -109,7 +109,6 @@ extern ulint srv_max_dirty_pages_pct;
extern ulint srv_force_recovery;
extern ulong srv_thread_concurrency;
extern ulong srv_commit_concurrency;
extern ulint srv_max_n_threads;

1
storage/innobase/srv/srv0srv.c
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@ -285,7 +285,6 @@ computer. Bigger computers need bigger values. Value 0 will disable the
concurrency check. */
ulong srv_thread_concurrency = 0;
ulong srv_commit_concurrency = 0;
os_fast_mutex_t srv_conc_mutex; /* this mutex protects srv_conc data
structures */