backward scan:是否能够按照相反的顺序返回结果。此属性只有在访问方法支持索引扫描才有意义。 Column Properties: => SELECT p.name, pg_index_column_has_property('seats_pkey', 1, p.name) FROM unnest(array['asc', 'desc', 'nulls_first', 'nulls_last', 'orderable','distance_orderable', '...
WHERE category_id=1 AND user_id=2; This is what Postgres 7.1 returns (exactlyasI expected) NOTICE:QUERY PLAN: Index Scan using mytable_categoryid_userid on mytable(cost=0.00..2.02 rows=1 width=16) EXPLAIN 以上是postgres的数据,可以看到该数据库在查询的时候使用了一个索引(一个好开始),而且...
SortKey: (CASE...END), aircrafts.modelDESC -> Seq Scanonaircrafts (3rows) (注意,最终执行计划会选择顺序扫描,忽略之前设置的enable_seqscan = off。因为这个设置并不会放弃表扫描,只是设置他的成本---查看costs on的执行计划) 若有使用索引,创建索引时指定排序的方向: 1 2 3 4 5 6 7 8 9 10 11...
support of index suffix truncation. The changes of above are backward-compatible, pg_upgrade doesn't need special handling of B-tree indexes for that. Bump catalog version Author: Anastasia Lubennikova with contribition by Alexander Korotkov and me Reviewed by: Peter Geoghegan, Tomas Vondra, ...
12](https://github.com/sequinstream/sequin "https://github.com/sequinstream/sequin")|An open source message stream built on Postgres.| 971 972 |[serialtest](https://github.com/wh201906/SerialTest "https://github.com/wh201906/SerialTest")|[0.3.5](https://github.com/wh201906/SerialTest...
Re: Index Scan Backward Slow From David Osborne Date: 01 May 2015, 11:06:57 Simple... that did it... thanks! dev=> create index on table(code,row_id); CREATE INDEX Time: 38088.482 ms dev=> explain (analyse,buffers) select row_id as last_row_id from table where code='XX' order...