Etsuro Fujita <fujita.ets...@lab.ntt.co.jp> wrote: > (2014/08/15 6:18), Rukh Meski wrote: >> Based on the feedback on my previous patch, I've separated only the >> LIMIT part into its own feature. This version plays nicely with >> inheritance. The intended use is splitting up big UPDATEs and DELETEs >> into batches more easily and efficiently. > > Before looking into the patch, I'd like to know the use cases in more > details.
There have been a few times I wanted something like this, so that it was easier to do an update that affects a very high percentage of rows in a table, while making the old version of the row no longer match the selection criteria for the UPDATE. There are workarounds using cursors or subselects returning ctid, but they are kludgy and error prone. Basically I wanted to alternate UPDATE of a subset of the rows with table VACUUM so that subsequent iterations can re-use space and avoid bloating the table. -- Kevin Grittner EDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers