Re: Bulk row fetching
От | Joe Conway |
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Тема | Re: Bulk row fetching |
Дата | |
Msg-id | 3D5BCBFB.10205@joeconway.com обсуждение исходный текст |
Ответ на | Re: Bulk row fetching ("Carmen Wai" <wai_carmen@hotmail.com>) |
Список | pgsql-general |
Carmen Wai wrote: > > I want to implement a similar mechanism as bulk row fetching in MFC ODBC > classes for postgresql. For the very large record sets, it can fetch the > first (let say) 100 records. After that, it can automatically fetch the > next 100 records WITHOUT executing the SQL statement again, it will save > lots of memory resouce / time. > > I only find that postgresql support : select * from table_name limit N > offset M, but if I do it in this way, the DB need multiple execution > which will take up lots of time. > > Do anyone gets any idea? It always helps to start with the manual ;-) See: http://www.postgresql.org/idocs/index.php?libpq-example.html for an example which uses a cursor. Instead of "FETCH ALL in mycursor", you can do something like "FETCH 100 in mycursor". See: http://www.postgresql.org/idocs/index.php?sql-fetch.html for more on FETCH. See: http://www.postgresql.org/idocs/index.php?sql-declare.html for more on declaring a cursor. HTH, Joe
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