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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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13
sql/sql_reload.cc
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@ -231,6 +231,7 @@ bool reload_acl_and_cache(THD *thd, unsigned long long options,
{
if ((options & REFRESH_READ_LOCK) && thd)
{
DBUG_ASSERT(!(options & REFRESH_FAST) && !tables);
/*
On the first hand we need write lock on the tables to be flushed,
on the other hand we must not try to aspire a global read lock
@ -249,9 +250,7 @@ bool reload_acl_and_cache(THD *thd, unsigned long long options,
tmp_write_to_binlog= 0;
if (thd->global_read_lock.lock_global_read_lock(thd))
return 1; // Killed
if (close_cached_tables(thd, tables,
((options & REFRESH_FAST) ? FALSE : TRUE),
thd->variables.lock_wait_timeout))
if (flush_tables(thd))
{
/*
NOTE: my_error() has been already called by reopen_tables() within
@ -274,11 +273,9 @@ bool reload_acl_and_cache(THD *thd, unsigned long long options,
make_global_read_lock_block_commit(thd) above since they could have
modified the tables too.
*/
if (WSREP(thd) &&
close_cached_tables(thd, tables, (options & REFRESH_FAST) ?
FALSE : TRUE, TRUE))
result= 1;
}
if (WSREP(thd) && flush_tables(thd))
result= 1;
}
else
{
if (thd && thd->locked_tables_mode)