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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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16
mysql-test/main/mdl_sync.result
View File

@ -3055,7 +3055,7 @@ disconnect con3;
#
CREATE TABLE t1(a INT) ENGINE=InnoDB;
SET debug_sync='open_tables_after_open_and_process_table SIGNAL ready WAIT_FOR go';
SELECT * FROM t1;
INSERT INTO t1 values (1);
connect con1,localhost,root,,;
SET debug_sync='now WAIT_FOR ready';
SET lock_wait_timeout=1;
@ -3063,7 +3063,21 @@ FLUSH TABLES WITH READ LOCK;
ERROR HY000: Lock wait timeout exceeded; try restarting transaction
SET debug_sync='now SIGNAL go';
connection default;
# After MDEV-5536, SELECT will not block FLUSH TABLES
SET debug_sync='RESET';
SET debug_sync='open_tables_after_open_and_process_table SIGNAL ready WAIT_FOR go';
SELECT * FROM t1;
connection con1;
SET debug_sync='now WAIT_FOR ready';
SET lock_wait_timeout=1;
FLUSH TABLES WITH READ LOCK;
SET debug_sync='now SIGNAL go';
connection default;
a
1
connection con1;
unlock tables;
connection default;
SET debug_sync='RESET';
DROP TABLE t1;
disconnect con1;