Re: Support for REINDEX CONCURRENTLY

On 2012-12-07 21:37:06 +0900, Michael Paquier wrote:
> Hi all,
>
> Long time this thread has not been updated...
> Please find attached the version 3 of the patch for support of REINDEX
> CONCURRENTLY.
> The code has been realigned with master up to commit da07a1e (6th December).
>
> Here are the things modified:
> - Improve code to use index_set_state_flag introduced by Tom in commit
> 3c84046
> - One transaction is used for each index swap (N transactions if N indexes
> reindexed at the same time)
> - Fixed a bug to drop the old indexes concurrently at the end of process
>
> The index swap is managed by switching the names of the new and old indexes
> using RenameRelationInternal several times. This API takes an exclusive
> lock on the relation that is renamed until the end of the transaction
> managing the swap. This has been discussed in this thread and other
> threads, but it is important to mention it for people who have not read the
> patch.

Won't working like this cause problems when dependencies towards that
index exist? E.g. an index-based constraint?

As you have an access exlusive lock you should be able to just switch
the relfilenodes of both and concurrently drop the *_cci index with the
old relfilenode afterwards, that would preserve the index states.

Right now I think clearing checkxmin is all you would need to other than
that. We know we don't need it in the concurrent context.

Greetings,

Andres Freund

--Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services