MDEV-25581 Allow user thread to do InnoDB fts cache sync

Problem:
========
  InnoDB FTS requesting the fts sync of the table once the fts
cache size reaches 1/10 of innodb_ft_cache_size. But fts_sync()
releases cache lock when writing the word. By doing this, InnoDB
insert thread increases the innodb fts cache memory and
SYNC operation will take more time to complete.

Solution:
=========
  Remove the fts sync operation(FTS_MSG_SYNC_TABLE) from
the fts optimize background thread. Instead of that,
allow user thread to sync the InnoDB fts cache when
the cache size exceeds 512 kb. User thread holds
cache lock while doing cache syncing, it make sure that
other threads doesn't add the docs into the cache.

Removed FTS_MSG_SYNC_TABLE and its related function
because we do remove the FTS_MSG_SYNC_TABLE message
itself.

Removed fts_sync_index_check() and all related
function because other threads doesn't add while
cache operation going on.

mysql-test/suite/innodb_fts/r/concurrent_insert.result

@@ -19,7 +19,7 @@ INSERT INTO t2 VALUES('mariadb');
 connection default;
 SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug ='+d,fts_instrument_sync_request,ib_optimize_wq_hang';
-SET DEBUG_SYNC= 'fts_instrument_sync_request
+SET DEBUG_SYNC= 'fts_sync_end
 		 SIGNAL drop_index_start WAIT_FOR sync_op';
 INSERT INTO t1 VALUES('Keyword');
 connect con1,localhost,root,,,;

mysql-test/suite/innodb_fts/r/sync.result

@@ -11,19 +11,19 @@ INSERT INTO t1(title) VALUES('database');
 connection con1;
 SET @old_dbug = @@SESSION.debug_dbug;
 SET debug_dbug = '+d,fts_instrument_sync_debug';
-SET DEBUG_SYNC= 'fts_write_node SIGNAL written WAIT_FOR selected';
+SET DEBUG_SYNC= 'fts_sync_end SIGNAL written WAIT_FOR selected';
 INSERT INTO t1(title) VALUES('mysql database');
 connection default;
 SET DEBUG_SYNC= 'now WAIT_FOR written';
 SET GLOBAL innodb_ft_aux_table="test/t1";
 SELECT * FROM INFORMATION_SCHEMA.INNODB_FT_INDEX_CACHE;
 WORD	FIRST_DOC_ID	LAST_DOC_ID	DOC_COUNT	DOC_ID	POSITION
+SELECT * FROM INFORMATION_SCHEMA.INNODB_FT_INDEX_TABLE;
+WORD	FIRST_DOC_ID	LAST_DOC_ID	DOC_COUNT	DOC_ID	POSITION
 database	2	3	2	2	0
 database	2	3	2	3	6
 mysql	1	3	2	1	0
 mysql	1	3	2	3	0
-SELECT * FROM INFORMATION_SCHEMA.INNODB_FT_INDEX_TABLE;
-WORD	FIRST_DOC_ID	LAST_DOC_ID	DOC_COUNT	DOC_ID	POSITION
 SET GLOBAL innodb_ft_aux_table=default;
 SELECT * FROM t1 WHERE MATCH(title) AGAINST('mysql database');
 FTS_DOC_ID	title
@@ -59,7 +59,7 @@ INSERT INTO t1(title) VALUES('mysql');
 INSERT INTO t1(title) VALUES('database');
 connection con1;
 SET debug_dbug = '+d,fts_instrument_sync_debug';
-SET DEBUG_SYNC= 'fts_write_node SIGNAL written WAIT_FOR inserted';
+SET DEBUG_SYNC= 'fts_sync_end SIGNAL written WAIT_FOR inserted';
 INSERT INTO t1(title) VALUES('mysql database');
 connection default;
 SET DEBUG_SYNC= 'now WAIT_FOR written';
@@ -70,14 +70,14 @@ SET debug_dbug = @old_dbug;
 SET GLOBAL innodb_ft_aux_table="test/t1";
 SELECT * FROM INFORMATION_SCHEMA.INNODB_FT_INDEX_CACHE;
 WORD	FIRST_DOC_ID	LAST_DOC_ID	DOC_COUNT	DOC_ID	POSITION
+database	4	4	1	4	6
+mysql	4	4	1	4	0
 SELECT * FROM INFORMATION_SCHEMA.INNODB_FT_INDEX_TABLE;
 WORD	FIRST_DOC_ID	LAST_DOC_ID	DOC_COUNT	DOC_ID	POSITION
 database	2	3	2	2	0
 database	2	3	2	3	6
-database	4	4	1	4	6
-mysql	1	4	3	1	0
-mysql	1	4	3	3	0
-mysql	1	4	3	4	0
+mysql	1	3	2	1	0
+mysql	1	3	2	3	0
 SET GLOBAL innodb_ft_aux_table=default;
 SELECT * FROM t1 WHERE MATCH(title) AGAINST('mysql database');
 FTS_DOC_ID	title

mysql-test/suite/innodb_fts/r/sync_block.result

@@ -30,6 +30,7 @@ connection con1;
 connection con2;
 /* conneciton con2 */ SELECT * FROM t1 WHERE MATCH(title) AGAINST('mysql database');
 FTS_DOC_ID	title
+1	mysql database
 connection default;
 # make con1 & con2 show up in mysql.slow_log
 SELECT SLEEP(2);
@@ -39,41 +40,11 @@ SLEEP(2)
 SELECT sql_text FROM mysql.slow_log WHERE query_time >= '00:00:02';
 sql_text
 INSERT INTO t1(title) VALUES('mysql database')
+SELECT * FROM t1 WHERE MATCH(title) AGAINST('mysql database')
 SET GLOBAL debug_dbug = @old_debug;
 TRUNCATE TABLE mysql.slow_log;
 DROP TABLE t1;
-# Case 2: Sync blocks DML(insert) on other tables.
-CREATE TABLE t1 (
-FTS_DOC_ID BIGINT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
-title VARCHAR(200),
-FULLTEXT(title)
-) ENGINE = InnoDB;
-CREATE TABLE t2(id INT);
-connection con1;
-SET GLOBAL debug_dbug='+d,fts_instrument_sync_request,fts_instrument_sync_sleep';
-SET DEBUG_SYNC= 'fts_instrument_sync_request SIGNAL begin WAIT_FOR continue';
-INSERT INTO t1(title) VALUES('mysql database');
-connection con2;
-SET DEBUG_SYNC= 'now WAIT_FOR begin';
-INSERT INTO t2 VALUES(1);
-connection default;
-SET DEBUG_SYNC= 'now SIGNAL continue';
-connection con1;
-/* connection con1 */ INSERT INTO t1(title) VALUES('mysql database');
-connection con2;
-/* conneciton con2 */ INSERT INTO t2 VALUES(1);
-connection default;
-SET DEBUG_SYNC = 'RESET';
-# make con1 & con2 show up in mysql.slow_log
-SELECT SLEEP(2);
-SLEEP(2)
-0
-# slow log results should be empty here.
-SELECT sql_text FROM mysql.slow_log WHERE query_time >= '00:00:02';
-sql_text
-SET GLOBAL debug_dbug = @old_debug;
-TRUNCATE TABLE mysql.slow_log;
-DROP TABLE t1,t2;
+SET DEBUG_SYNC=RESET;
 disconnect con1;
 disconnect con2;
 # Restore slow log settings.

mysql-test/suite/innodb_fts/t/concurrent_insert.test

@@ -31,7 +31,7 @@ INSERT INTO t2 VALUES('mariadb');
 connection default;
 SET @saved_dbug = @@GLOBAL.debug_dbug;
 SET GLOBAL debug_dbug ='+d,fts_instrument_sync_request,ib_optimize_wq_hang';
-SET DEBUG_SYNC= 'fts_instrument_sync_request
+SET DEBUG_SYNC= 'fts_sync_end
 		 SIGNAL drop_index_start WAIT_FOR sync_op';
 send INSERT INTO t1 VALUES('Keyword');
 

mysql-test/suite/innodb_fts/t/sync.test

@@ -26,7 +26,7 @@ connection con1;
 SET @old_dbug = @@SESSION.debug_dbug;
 SET debug_dbug = '+d,fts_instrument_sync_debug';
 
-SET DEBUG_SYNC= 'fts_write_node SIGNAL written WAIT_FOR selected';
+SET DEBUG_SYNC= 'fts_sync_end SIGNAL written WAIT_FOR selected';
 
 send INSERT INTO t1(title) VALUES('mysql database');
 
@@ -73,7 +73,7 @@ connection con1;
 
 SET debug_dbug = '+d,fts_instrument_sync_debug';
 
-SET DEBUG_SYNC= 'fts_write_node SIGNAL written WAIT_FOR inserted';
+SET DEBUG_SYNC= 'fts_sync_end SIGNAL written WAIT_FOR inserted';
 
 send INSERT INTO t1(title) VALUES('mysql database');
 

mysql-test/suite/innodb_fts/t/sync_block.test

@@ -65,53 +65,7 @@ SET GLOBAL debug_dbug = @old_debug;
 TRUNCATE TABLE mysql.slow_log;
 
 DROP TABLE t1;
-
---echo # Case 2: Sync blocks DML(insert) on other tables.
-CREATE TABLE t1 (
-        FTS_DOC_ID BIGINT UNSIGNED AUTO_INCREMENT NOT NULL PRIMARY KEY,
-        title VARCHAR(200),
-        FULLTEXT(title)
-) ENGINE = InnoDB;
-
-CREATE TABLE t2(id INT);
-
-connection con1;
-
-SET GLOBAL debug_dbug='+d,fts_instrument_sync_request,fts_instrument_sync_sleep';
-
-SET DEBUG_SYNC= 'fts_instrument_sync_request SIGNAL begin WAIT_FOR continue';
-
-send INSERT INTO t1(title) VALUES('mysql database');
-
-connection con2;
-
-SET DEBUG_SYNC= 'now WAIT_FOR begin';
-
-send INSERT INTO t2 VALUES(1);
-
-connection default;
-SET DEBUG_SYNC= 'now SIGNAL continue';
-
-connection con1;
---echo /* connection con1 */ INSERT INTO t1(title) VALUES('mysql database');
---reap
-
-connection con2;
---echo /* conneciton con2 */ INSERT INTO t2 VALUES(1);
---reap
-
-connection default;
-SET DEBUG_SYNC = 'RESET';
--- echo # make con1 & con2 show up in mysql.slow_log
-SELECT SLEEP(2);
--- echo # slow log results should be empty here.
-SELECT sql_text FROM mysql.slow_log WHERE query_time >= '00:00:02';
-
-SET GLOBAL debug_dbug = @old_debug;
-TRUNCATE TABLE mysql.slow_log;
-
-DROP TABLE t1,t2;
-
+SET DEBUG_SYNC=RESET;
 disconnect con1;
 disconnect con2;