????10???????????????tmp_table_size??max_heap_table_size?????????????????????1G?????2????????????????????????????????ù??????????????OOM?????????????Щ?????????????磺sort_buffer_size??join_buffer_size??read_buffer_size??read_rnd_buffer_size???????????????ù???
????11????????????鯔?????MyISAM??????????????key_buffer_size?????32M?????????????????query cache?????
????3.3??????Schema???淶??SQL??y???
?????????о????????????????????MySQLЧ???Schema???淶??SQL??y??飺
????1?????е?InnoDB??????????????????????????????????????????????????????????????????InnoDB???????????????????????TokuDB???????
????2????γ???????????????￡????????????С???????????????????????NOT NULL?????????????????????
????3????????????TEXT/BLOB??????????????????????????У????????????????????SELECT*????????????
????4???????????????????????У??????ζ?SELECT*?????????????????????????????????ЩTEXT/BLOB?У?
????5???????VARCHAR(N)?д????????????????50%????????С??????????????????????????80%?????????????????????????е????????????
????6?????????￡??????????????????????JOINд????
????7??????????????????????????????￡???????????????
????8????????????????????С??????????????????????????????????????????С?????????????
????9???????????????????????????α?????????????????????????????????????
????10??????????????????????????????????????Щ??????Cardinality???С????????????е??????????255?????в?????????????????
????11?????????????SQL???????????????????????????????Ч??????
????3.3??????????
????????MySQL???????????????????У?
????1?????????????????С??????10GB????????????????1????????????????????8KB???????????????????Щ??????MySQL???????????????????????????????????????????????ONLINE DDL????????
????2???????????mysqld????????????棬????????OOM kill???????????SWAP???????
????3???????????????????????????????????ü?????????????????????????????????????????????????????
????4?????????pt-duplicate-key-checker??鰱?????????????????????pt-index-usage?????鰱??????????????????
????5????????slow query log????pt-query-digest??????з?????????Anemometer??????slow query??????????slow query?????к????????????
????6???????pt-kill??????????SQL????Percona?汾???и????innodb_kill_idle_transaction??????ù????
????7?????pt-online-schema-change????????ONLINE DDL????
????8?????????pt-table-checksum??pt-table-sync????鰱???mysql???????????????