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ha_innodb.cc:

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Add comments about why the InnoDB latching order is obeyed also for the MySQL query cache mutex; add an error printf if that is not the case
sync0sync.h:
  Assign sync0sync.h ranks also for the MySQL query cache mutex and the MySQL binlog mutex; the latching order must be obeyed also for these
row0ins.c:
  Add a comment why the query cache invalidate operation cannot deadlock in a cascaded FOREIGN KEY operation


innobase/row/row0ins.c:
  Add a comment why the query cache invalidate operation cannot deadlock in a cascaded FOREIGN KEY operation
innobase/include/sync0sync.h:
  Assign sync0sync.h ranks also for the MySQL query cache mutex and the MySQL binlog mutex; the latching order must be obeyed also for these
sql/ha_innodb.cc:
  Add comments about why the InnoDB latching order is obeyed also for the MySQL query cache mutex; add an error printf if that is not the case
This commit is contained in:
unknown 2005-01-12 18:25:39 +02:00
commit 871fdda191
3 changed files with 25 additions and 2 deletions
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20
sql/ha_innodb.cc
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@ -765,7 +765,14 @@ returns TRUE for all tables in the query.
If thd is not in the autocommit state, this function also starts a new
transaction for thd if there is no active trx yet, and assigns a consistent
read view to it if there is no read view yet. */
read view to it if there is no read view yet.
Why a deadlock of threads is not possible: the query cache calls this function
at the start of a SELECT processing. Then the calling thread cannot be
holding any InnoDB semaphores. The calling thread is holding the
query cache mutex, and this function will reserver the InnoDB kernel mutex.
Thus, the 'rank' in sync0sync.h of the MySQL query cache mutex is above
the InnoDB kernel mutex. */
my_bool
innobase_query_caching_of_table_permitted(
@ -802,6 +809,13 @@ innobase_query_caching_of_table_permitted(
trx = check_trx_exists(thd);
}
if (trx->has_search_latch) {
ut_print_timestamp(stderr);
fprintf(stderr,
" InnoDB: Error: the calling thread is holding the adaptive search\n"
"InnoDB: latch though calling innobase_query_caching_of_table_permitted\n");
}
innobase_release_stat_resources(trx);
if (!(thd->options & (OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN))) {
@ -877,6 +891,10 @@ innobase_invalidate_query_cache(
ulint full_name_len) /* in: full name length where also the null
chars count */
{
/* Note that the sync0sync.h rank of the query cache mutex is just
above the InnoDB kernel mutex. The caller of this function must not
have latches of a lower rank. */
/* Argument TRUE below means we are using transactions */
#ifdef HAVE_QUERY_CACHE
query_cache.invalidate((THD*)(trx->mysql_thd),