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13884cf206
Analysis: Current implementation will write and read at least one block (sort_buffer_size bytes) from disk / index even if that block does not contain any records. Fix: Avoid writing / reading empty blocks to temporary files (disk).
31 lines
1.4 KiB
Plaintext
31 lines
1.4 KiB
Plaintext
CREATE TABLE `test_wo_keys` (
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`f01` int AUTO_INCREMENT,
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`f02` bigint, `f03` bigint, `f04` enum('a','b'),
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`f05` date, `f06` int, `f07` int, `f08` double, `f09` int,
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`f10` bigint, `f11` double, `f12` enum('a','b','c','d','e'),
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`f13` int, `f14` int, `f15` varchar(255), `f16` int, `f17` int, `f18` int,
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`f19` double, `f20` double, `f21` double, `f22` double, `f23` double, `f24` tinyint,
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`f25` double, `f26` double, `f27` double, `f28` double, `f29` int unsigned,
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`f30` int unsigned, `f31` bigint, `f32` int unsigned, `f33` bigint,
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`f34` int unsigned, `f35` int unsigned,
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PRIMARY KEY `f01` (`f01`)
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) ENGINE=InnoDB DEFAULT CHARSET=latin1;
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show status like '%merge_buffers%';
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Variable_name Value
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Innodb_os_merge_buffers_written 0
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Innodb_os_merge_buffers_read 0
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Innodb_os_merge_buffers_merged 0
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ALTER TABLE test_wo_keys
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ADD KEY `f06` (`f06`), ADD KEY `f05` (`f05`), ADD KEY `f04` (`f04`), ADD KEY `f23` (`f23`),
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ADD KEY `f10` (`f10`), ADD KEY `f11` (`f11`), ADD KEY `f09` (`f09`), ADD KEY `f22` (`f22`),
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ADD KEY `f21` (`f21`), ADD KEY `f07` (`f07`), ADD KEY `f08` (`f08`), ADD KEY `f18` (`f18`),
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ADD KEY `f19` (`f19`), ADD KEY `f20` (`f20`), ADD KEY `f29` (`f29`,`f31`,`f33`),
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ADD KEY `f35` (`f35`), ADD KEY `f25` (`f25`), ADD KEY `f26` (`f26`),
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ADD KEY `f27` (`f27`), ADD KEY `f28` (`f28`);
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show status like '%merge_buffers%';
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Variable_name Value
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Innodb_os_merge_buffers_written 0
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Innodb_os_merge_buffers_read 0
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Innodb_os_merge_buffers_merged 0
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DROP TABLE test_wo_keys;
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