HAMA 블로그

Table of ContentsIndex TypesWhy is my query not using an index?Partial IndexesExpression IndexesUnique IndexesMulti-column IndexesB-Trees and sortingManaging and Maintaining indexesThere are many types of indexes in Postgres, as well as different ways to use them. In this article we give an overview of the types of indexes available, and explain different ways of using and maintaining the most c..

PostgreSQL Date & Time Function 해당 날짜의 데이터 select count(watt_max) from tbl_test_watt3_sm2ch_min where to_char(regdate, 'YYYY-MM-DD') = '2016-10-17' 소요시간 : 124초 (150만건) (하루: 20*60*60*24 = 1,728,000) 이렇게 하면 망함! 해당 날짜의 데이터 select count(watt) from tbl_test_watt_lsh where regdate >= date '2016-10-17'and regdate < date '2016-10-17' + integer '1' // 여기선 하루 소요시간 : 634ms (150만건) (하루: 20*60*60*24 = 1,728,..

Data TypesNameAliasesDescriptionbigintint8signed eight-byte integerbigserialserial8autoincrementing eight-byte integerbit [ (n) ] fixed-length bit stringbit varying [ (n) ]varbitvariable-length bit stringbooleanboollogical Boolean (true/false)box rectangular box on a planebytea binary data ("byte array")character [ (n) ]char [ (n) ]fixed-length character stringcharacter varying [ (n) ]varchar [ ..