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Optimize flush tables with read lock (FTWRL) to not wait for select's

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Part of MDEV-5336 Implement LOCK FOR BACKUP

The idea is that instead of waiting in close_cached_tables() for all
tables to be closed, we instead call flush_tables() that does:
- Flush not used objects in table cache to free memory
- Collect all tables that are open
- Call HA_EXTRA_FLUSH on the objects, to get them into "closed state"
- Added HA_EXTRA_FLUSH support to archive and CSV
- Added multi-user protection to HA_EXTRA_FLUSH in MyISAM and Aria

The benefit compared to old code is:
- FTWRL doesn't have to wait for long running read operations or
  open HANDLER's
This commit is contained in:
Monty
2018-10-09 18:55:18 +03:00
parent 306b7a2243
commit 163b34fe25
35 changed files with 456 additions and 81 deletions
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4
sql/table_cache.cc
View File

@ -406,7 +406,7 @@ void tc_add_table(THD *thd, TABLE *table)
@return TABLE object, or NULL if no unused objects.
*/
static TABLE *tc_acquire_table(THD *thd, TDC_element *element)
TABLE *tc_acquire_table(THD *thd, TDC_element *element)
{
uint32 n_instances=
my_atomic_load32_explicit((int32*) &tc_active_instances,
@ -657,7 +657,7 @@ void tdc_start_shutdown(void)
tdc_size= 0;
tc_size= 0;
/* Free all cached but unused TABLEs and TABLE_SHAREs. */
close_cached_tables(NULL, NULL, FALSE, LONG_TIMEOUT);
purge_tables(true);
}
DBUG_VOID_RETURN;
}