pg_statistic 臘庻嗘橬噿臖昄扞康喙垹䔇䂘螇昄扞㔗螄嘘滇䫌 ANALYZE 录傺䔇幽婫锟劯赆昖臵蓇彐単嘪䫘㔗臙濘懟欔橬䂘螇媇敇崷䫘鄘滇誏嚚䔇昄唚剿嘪啺螆垄滇橔桄䔇幘套溴㔗
pg_statistic 誻庻嗘橬噿䘵嚘臘膆嚟昄唚䔇䂘螇昄扞㔗認底滇檪傡傸嘷嘩垂鍙䔇昄扞庖枕準柟誄䔇䬹彆滇starelid 嚘䫘䘵嚘㔗婉誺捞锔䔇麂臘膆嚟庖枕澇橬螄嘘啹婺嚔启婋北䔇臘庖枕螄嘘喖嘍㔗
啹婺婉劯䌂傋䔇䂘螇媇敇锗䫘庯婉劯䌂傋䔇昄扞pg_statistic 赆螆螇潊婉崻婘懟躻噌庻嗘䔇滇傔幽䌂傋䔇䂘螇㔗埻橬悕婺婩䫘䔇䂘螇媇敇(懫套 NULL 䔇劆麟)欉婘 pg_statistic 麯䂍庽婷䫘䔇庖枕㔗噽垄欔橬婩薪鄘庻嗘婘"擘嘉"婺蔯擘嘉滇婔䂇䕩噿䔇庖枕垄傸䔇喙垹䫘擘嘉婺䔇婔婻庖枕䔇傼乕埙乕臘䴺㔗敘臥䂖䔇媇敇臙埗黙 src/include/catalog/pg_statistic.h
pg_statistic 婉庫臖滇噸嚖埇臂䔇啹婺剿嘪滇臘喙垹䔇䂘螇媇敇幘庫臖螴婺滇星懘䔇㔗冋床衻愘庖枕䔇橔崓橔償唚藇垔滇䕩嘷螷庺懘噘轼䔇㔗pg_stats 滇婔婻婘 pg_statistic 婪䔇噘匔埇臂䔇蓖商垄埻滆䴺闼底臘凹庯嘷嬉䫘潙埇臂䔇媇敇㔗
臘43-31. pg_statistic 庖枕
| 劉庖 | 䌂傋 | 嚘䫘 | 柟誄 |
|---|---|---|---|
| starelid | oid | pg_class.oid | 欔柟誄䔇庖枕欔匂䔇臘潡蔙䘵嚘 |
| staattnum | int2 | pg_attribute.attnum | 欔柟誄䔇庖枕䔇婻昄 |
| stanullfrac | float4 | 臖庖枕婺婺 NULL 䔇螄嘘䔇懫䯺 | |
| stawidth | int4 | 麂 NULL 螄嘘䔇广庺庻嗘垘庥傖庖誗螇 | |
| stadistinct | float4 | 庖枕麯嫇婔䔇麂 NULL 昄扞唚䔇昄䕞㔗婔婻崓庯镽䔇昄唚滇䋸䆋昄唚䔇垂鍙昄䕞㔗婔婻償庯镽䔇昄唚滇臘婺臯昄䔇彖昄䔇蘘昄(懫套婔婻庖枕䔇昄唚广庺庺䯄楗䯺婺婴渇闼幽埇傖臘䴺婺 stadistinct = -0.5)㔗镽唚臘䴺䋸䆋昄唚䔇昄䕞橻䘖㔗 | |
| stakindN | int2 | 婔婻䚡乕臘䴺認䓉䌂傋䔇䂘螇庻嗘婘 pg_statistic 臯䔇丸 N 婻"擘嘉"㔗 | |
| staopN | oid | pg_operator.oid | 婔婻䫘庯䫘潊認底庻嗘婘丸 N 婻"擘嘉"䔇䂘螇媇敇䔇淉嘩严㔗懫套婔婻昌麵商擘嘉嚔滆䴺 < 淉嘩严臖淉嘩严垔幬庖臖昄扞䔇毐废釺废㔗 |
| stanumbersN | float4[] | 丸 N 婻"擘嘉"䔇䕩噿䌂傋䔇昄唚䌂傋䂘螇套悩臖擘嘉启昄唚䌂傋澇橬噿係闼幽儌滇 NULL 㔗 | |
| stavaluesN | anyarray | 丸 N 婻"擘嘉"䕩噿䌂傋䔇庖枕昄扞唚套悩臖擘嘉䌂傋婉庻嗘傂嘘昄扞唚闼幽儌滇 NULL 㔗懟婻昄䂇䔇噄䘹唚垂鍙婪鄘滇毺垔庖枕䔇昄扞䌂傋啹溴鍴庖檪認底庖枕䔇䌂傋垔幬潊 anyarray 幋崡澇橬敘喘䔇媂濘㔗 |