slow update
От | Janning Vygen |
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Тема | slow update |
Дата | |
Msg-id | 200207261314.g6QDEcM32601@janning.planwerk6.local обсуждение исходный текст |
Ответы |
Re: slow update
|
Список | pgsql-general |
Hi, i need to update a table in a database and i already managed it to copy new data in a temproary table with 'copy' command very quick. what i have is CREATE TABLE tmp (id int4, val1 int4, val2 int4); CREATE TABLE real (id int4 PRIMARY KEY, val1 int4, val2 int4); not all id s in real have appropiate values in temp. now i just want to merge these tables and i tried: UPDATE real SET val1=(SELECT val1 FROM temp WHERE temp.id = real.id ), val2=(SELECT val2 FROM temp WHERE temp.id = real.id ) WHERE id IN (SELECT temp.id FROM temp); update is taking very long time. there is an index on real but not on the columns which i update and theer are no triggers at all. but there are many, many rows in real. Can anybody give me a hint to a faster way updating the data?? it looks like a very easy task for the database just to merge to tables, but maybe its not? kind regards, janning
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