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SET @saved_frequency = @@GLOBAL.innodb_purge_rseg_truncate_frequency;
SET GLOBAL innodb_purge_rseg_truncate_frequency = 1;
SET @saved_include_delete_marked = @@GLOBAL.innodb_stats_include_delete_marked;
SET GLOBAL innodb_stats_include_delete_marked = ON;
SET @saved_traditional = @@GLOBAL.innodb_stats_traditional;
SET GLOBAL innodb_stats_traditional=false;
SET @saved_modified_counter = @@GLOBAL.innodb_stats_modified_counter;
SET GLOBAL innodb_stats_modified_counter=1;
CREATE TABLE t1 (id SERIAL, val INT UNSIGNED NOT NULL, KEY(val))
ENGINE=INNODB STATS_PERSISTENT=1,STATS_AUTO_RECALC=1;
CREATE TABLE t2 LIKE t1;
INSERT INTO t1 (val) SELECT 4 FROM seq_1_to_16;
ANALYZE TABLE t1;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
connect con1, localhost, root,,;
START TRANSACTION;
DELETE FROM t1;
SELECT COUNT(*) FROM t1;
connection default;
# With innodb_stats_include_delete_marked=ON,
# DELETE must not affect statistics before COMMIT.
EXPLAIN SELECT * FROM t1 WHERE val=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref val val 4 const 1 Using index
connection con1;
COUNT(*)
0
ROLLBACK;
SELECT COUNT(*) FROM t1;
COUNT(*)
16
EXPLAIN SELECT * FROM t1 WHERE val=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref val val 4 const 16 Using index
BEGIN;
DELETE FROM t1;
COMMIT;
SELECT COUNT(*) FROM t1;
COUNT(*)
0
connection default;
BEGIN;
INSERT INTO t2 (val) SELECT 4 FROM seq_1_to_16;
# The INSERT will show up before COMMIT.
EXPLAIN SELECT * FROM t2 WHERE val=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref val val 4 const 16 Using index
SELECT COUNT(*) FROM t2;
COUNT(*)
16
# The ROLLBACK of the INSERT must affect the statistics.
ROLLBACK;
SELECT COUNT(*) FROM t2;
COUNT(*)
0
connection con1;
EXPLAIN SELECT * FROM t2 WHERE val=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ref val val 4 const 1 Using index
InnoDB 0 transactions not purged
# After COMMIT and purge, the DELETE must show up.
EXPLAIN SELECT * FROM t1 WHERE val=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref val val 4 const 1 Using index
SET GLOBAL innodb_stats_include_delete_marked = OFF;
BEGIN;
INSERT INTO t1 (val) SELECT 4 FROM seq_1_to_16;
EXPLAIN SELECT * FROM t1 WHERE val=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref val val 4 const 16 Using index
ROLLBACK;
EXPLAIN SELECT * FROM t1 WHERE val=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref val val 4 const 1 Using index
BEGIN;
INSERT INTO t1 (val) SELECT 4 FROM seq_1_to_16;
COMMIT;
EXPLAIN SELECT * FROM t1 WHERE val=4;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref val val 4 const 16 Using index
BEGIN;
DELETE FROM t1;
SELECT COUNT(*) FROM t1;
COUNT(*)
0
# With innodb_stats_include_delete_marked=OFF,
# DELETE must affect statistics even before COMMIT.
# However, if there was a WHERE condition,
# ha_innobase::records_in_range() would count the delete-marked records.
EXPLAIN SELECT * FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL val 4 NULL 16 Using index
ROLLBACK;
EXPLAIN SELECT * FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL val 4 NULL 16 Using index
SELECT COUNT(*) FROM t1;
COUNT(*)
16
disconnect con1;
connection default;
DROP TABLE t1,t2;
SET GLOBAL innodb_stats_include_delete_marked = @saved_include_delete_marked;
SET GLOBAL innodb_stats_traditional = @saved_traditional;
SET GLOBAL innodb_stats_modified_counter = @saved_modified_counter;
SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
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