Re: Concurrently option for reindexdb

On Mon, Aug 25, 2014 at 3:36 PM, Sawada Masahiko <sawada(dot)mshk(at)gmail(dot)com> wrote:
> Attached WIP patch adds "-C (--concurrently)" option for reindexdb
> command for concurrently reindexing.
> If we specify "-C" option with any table then reindexdb do reindexing
> concurrently with minimum lock necessary.
> Note that we cannot use '-s' option (for system catalog) and '-C'
> option at the same time.
> This patch use simple method as follows.
>
> 1. Do "CREATE INDEX CONCURRENTLY" new index which has same definition
> as target index
> 2. Aquire ACCESS EXCLUSIVE LOCK to target table( and transaction starts)
> 3. Swap old and new index
> 4. Drop old index
> 5. COMMIT
>
> These process are based on pg_repack(or pg_reorg) does, done via SQL.

This would be a useful for users, but I am not sure that you can call
that --concurrently as the rename/swap phase requires an exclusive
lock, and you would actually block a real implementation of REINDEX
CONCURRENTLY (hm...).

> ToDo
> - Multi language support for log message.
Why? I am not sure that's something you should deal with.
--
Michael