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Postgresql updating millions of rows

In that case maybe I'm better off inserting all of the deleted keys into a side table and doing a merge or hash join between the side table and the child table... Brian: One approach we use for large tables is to partition and then drop partitions as the data becomes obsolete. Our general rule is to never delete data from a table because it is too slow.

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I thought a cursor would break the job into chunks and most importantly COMMIT the chunk of data in the UPDATE command at the end of the loop.2) is there any other way to restore performance other than restoring the database?-------------------------------- ----------------------------- ----------- | Column | Type | Modifiers | -------------------------------- ----------------------------- ----------- | key | character varying(36) | not null | | category_id | integer | | | owner_id | integer | | -------------------------------- ----------------------------- ----------- WITH number_of_rows are 100, 200, 500, 1000, 2000.We have found this to be the preferred approach regardless of database platform.-Jerry Jerry Champlin|Absolute Performance Inc.|Mobile: 303-588-2547 -----Original Message----- From: pgsql-performance-owner(at)postgresql(dot)org [mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of Brian Cox Sent: Monday, February 02, 2009 AM To: pgsql-performance(at)postgresql(dot)org Subject: [PERFORM] Deleting millions of rows I'm using 8.3.5. Through psql: delete from ts_defects; Result: out of memory/Can't allocate size: 32 I then did 10 or so deletes to get rid of the rows.Suppose you want to update a column with the value 0, if it that column contains negative value.

Let us also assume that there are over 2 million row in that column that has a negative value.

I'm not sure how PG handles subqueries but that could be an issue since it may get executed once per row.

A non-specific answer here will be too general, so you need to give us a scenario to solve.

Many a times, you come across a requirement to update a large table in SQL Server that has millions of rows (say more than 5 millions) in it.

In this article I will demonstrate a fast way to update rows in a large table Consider a table called which has more than 5 millions rows.

Consider the following code: The above code updates 10000 rows at a time and the loop continues till @@rowcount has a value greater than zero. Best practices while updating large tables in SQL Server1.