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b1f2d3a8c8
We should not need anywhere near 32 bits of entropy, so we might just limit ourselves to a 32-bit random number generator. Also, it might be cheaper to use exclusive-or, bit shifting and conditional jumps, instead of multiplication and addition. We use relaxed atomic operations on the global random number generator state in order in an attempt to silence any warnings about race conditions. There is an obvious race condition between the load and store in ut_rnd_gen(), but we do not think that it matters much that the state of the random number generator could 'stutter'. This change seems makes the 'uncompress_ops' nondeterministic in innodb_zip.cmp_per_index after the restart. It looks like there is an inherent race condition in the test, because the table could be opened for InnoDB statistics recalculation already before innodb_cmp_per_index_enabled was set. We might end up having uncompress_ops anywhere between 0 and 9, or perhaps even more. Let us remove that part of the test.
76 lines
1.7 KiB
Plaintext
76 lines
1.7 KiB
Plaintext
SET @save_enabled= @@GLOBAL.innodb_cmp_per_index_enabled;
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SET GLOBAL innodb_cmp_per_index_enabled=ON;
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SELECT * FROM information_schema.innodb_cmp_per_index;
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CREATE TABLE t (
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a INT,
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b VARCHAR(512),
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c VARCHAR(16),
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PRIMARY KEY (a),
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INDEX (b(512)),
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INDEX (c(16))
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) ENGINE=INNODB KEY_BLOCK_SIZE=2;
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SELECT
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database_name,
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table_name,
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index_name,
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compress_ops,
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compress_ops_ok,
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uncompress_ops
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FROM information_schema.innodb_cmp_per_index
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ORDER BY 1, 2, 3;
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database_name test
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table_name t
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index_name b
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compress_ops 1
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compress_ops_ok 1
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uncompress_ops 0
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database_name test
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table_name t
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index_name c
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compress_ops 1
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compress_ops_ok 1
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uncompress_ops 0
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database_name test
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table_name t
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index_name PRIMARY
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compress_ops 1
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compress_ops_ok 1
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uncompress_ops 0
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BEGIN;
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COMMIT;
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ALTER TABLE t DROP INDEX c;
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GRANT USAGE ON *.* TO 'tuser01'@'localhost' IDENTIFIED BY 'cDJvI9s_Uq';
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FLUSH PRIVILEGES;
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connect con1,localhost,tuser01,cDJvI9s_Uq,;
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connection con1;
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SELECT * FROM information_schema.innodb_cmp_per_index;
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ERROR 42000: Access denied; you need (at least one of) the PROCESS privilege(s) for this operation
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connection default;
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disconnect con1;
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DROP USER 'tuser01'@'localhost';
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SELECT
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database_name,
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table_name,
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index_name,
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CASE WHEN compress_ops=47 and @@innodb_compression_level IN (4,8,9) THEN 65
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ELSE compress_ops END as compress_ops,
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CASE WHEN compress_ops_ok=47 and @@innodb_compression_level IN (4,8,9) THEN 65
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ELSE compress_ops_ok END as compress_ops_ok,
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uncompress_ops
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FROM information_schema.innodb_cmp_per_index
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ORDER BY 1, 2, 3;
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database_name test
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table_name t
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index_name b
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compress_ops 43
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compress_ops_ok 43
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uncompress_ops 0
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database_name test
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table_name t
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index_name PRIMARY
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compress_ops 65
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compress_ops_ok 65
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uncompress_ops 0
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DROP TABLE t;
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SET GLOBAL innodb_cmp_per_index_enabled=@save_enabled;
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