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Fix Bug#40760 "set global innodb_thread_concurrency = 0;" is not safe

The config param innodb_thread_concurrency is dynamically set and is
read when a thread enters/exits innodb. If the value is changed between
the enter and exit time the behaviour becomes erratic.
The fix is not to use srv_thread_concurrency when exiting, instead use
the flag trx->declared_to_be_inside_innodb.

rb://57

Approved by: Marko
This commit is contained in:
inaam 2008-11-24 20:06:50 +00:00
parent fff52da321
commit 9b4f5f6f9f
3 changed files with 20 additions and 13 deletions
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2
handler/ha_innodb.cc
View file

@ -461,7 +461,7 @@ innodb_srv_conc_exit_innodb(
/*========================*/
trx_t* trx) /* in: transaction handle */
{
if (UNIV_LIKELY(!srv_thread_concurrency)) {
if (UNIV_LIKELY(!trx->declared_to_be_inside_innodb)) {
return;
}

27
srv/srv0srv.c
View file

@ -283,13 +283,16 @@ ulong srv_commit_concurrency = 0;
os_fast_mutex_t srv_conc_mutex; /* this mutex protects srv_conc data
structures */
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 */
lint srv_conc_n_threads = 0; /* number of transactions that
have declared_to_be_inside_innodb
set. It used to be a non-error
for this value to drop below
zero temporarily. This is no
longer true. We'll, however,
keep the lint datatype to add
assertions to catch any corner
cases that we may have
missed. */
ulint srv_conc_n_waiting_threads = 0; /* number of OS threads waiting in the
FIFO for a permission to enter InnoDB
*/
@ -1020,6 +1023,8 @@ retry:
return;
}
ut_ad(srv_conc_n_threads >= 0);
if (srv_conc_n_threads < (lint)srv_thread_concurrency) {
srv_conc_n_threads++;
@ -1146,6 +1151,8 @@ srv_conc_force_enter_innodb(
return;
}
ut_ad(srv_conc_n_threads >= 0);
os_fast_mutex_lock(&srv_conc_mutex);
srv_conc_n_threads++;
@ -1167,11 +1174,6 @@ srv_conc_force_exit_innodb(
{
srv_conc_slot_t* slot = NULL;
if (UNIV_LIKELY(!srv_thread_concurrency)) {
return;
}
if (trx->mysql_thd != NULL
&& thd_is_replication_slave_thread(trx->mysql_thd)) {
@ -1185,6 +1187,7 @@ srv_conc_force_exit_innodb(
os_fast_mutex_lock(&srv_conc_mutex);
ut_ad(srv_conc_n_threads > 0);
srv_conc_n_threads--;
trx->declared_to_be_inside_innodb = FALSE;
trx->n_tickets_to_enter_innodb = 0;

4
trx/trx0trx.c
View file

@ -287,6 +287,10 @@ trx_free(
"InnoDB: inside InnoDB.\n", stderr);
trx_print(stderr, trx, 600);
putc('\n', stderr);
/* This is an error but not a fatal error. We must keep
the counters like srv_conc_n_threads accurate. */
srv_conc_force_exit_innodb(trx);
}
if (trx->n_mysql_tables_in_use != 0