On May 15, 2013, at 11:52 PM, Thomas Kellerer <spam_ea...@gmx.net> wrote:
> Sajeev Mayandi, 16.05.2013 07:01: >> Hi, >> >> Our company is planning to move to postreSQL. We were initially using >> sybase where upsert functionality was available using "insert on >> existing update" clause. I know there multiple ways to fix this >> using RULE or separate function in postgresql. But I would like to >> know which version of postgresql has support for upsert planned using >> an official syntax. I have postgresql 9.2 which does not have this >> feature, if its planned in near future, I would rather wait to >> migrate to PostgreSQL. >> > > You can use writeable CTEs for this purpose. > > There are several examples out there: > > http://www.xzilla.net/blog/2011/Mar/Upserting-via-Writeable-CTE.html > http://www.depesz.com/2011/03/16/waiting-for-9-1-writable-cte/ > http://www.depesz.com/2012/06/10/why-is-upsert-so-complicated/ > > http://stackoverflow.com/a/8702291/330315 One thing I didn't see mentioned in two of the links -- they mention race conditions, where multiple writers can still cause the faked UPSERT to fail. This can be avoided using SERIALIZABLE transactions, now that Postgres has SSI. http://wiki.postgresql.org/wiki/SSI I can vouch that we use writable CTEs and SERIALIZABLE to implement UPSERT in production with no issues thus far. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
