Re: Support for REINDEX CONCURRENTLY

On Tue, Mar 19, 2013 at 3:24 AM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:

> On Wed, Mar 13, 2013 at 9:04 PM, Michael Paquier
> <michael(dot)paquier(at)gmail(dot)com> wrote:
> > I have been working on improving the code of the 2 patches:
> > 1) reltoastidxid removal:
> <snip>
> > - Fix a bug with pg_dump and binary upgrade. One valid index is necessary
> > for a given toast relation.
>
> Is this bugfix related to the following?
>
> appendPQExpBuffer(upgrade_query,
> - "SELECT c.reltoastrelid,
> t.reltoastidxid "
> + "SELECT c.reltoastrelid,
> t.indexrelid "
> "FROM pg_catalog.pg_class c LEFT
> JOIN "
> - "pg_catalog.pg_class t ON
> (c.reltoastrelid = t.oid) "
> - "WHERE c.oid =
> '%u'::pg_catalog.oid;",
> + "pg_catalog.pg_index t ON
> (c.reltoastrelid = t.indrelid) "
> + "WHERE c.oid =
> '%u'::pg_catalog.oid AND t.indisvalid "
> + "LIMIT 1",
>
Yes.

> Don't indisready and indislive need to be checked?
>
An index is valid if it is already ready and line. We could add such check
for safely but I don't think it is necessary.

Why is LIMIT 1 required? The toast table can have more than one toast
> indexes?
>
It cannot have more than one VALID index, so yes as long as a check on
indisvalid is here there is no need to worry about a LIMIT condition. I
only thought of that as a safeguard. The same thing applies to the addition
of a condition based on indislive and indisready.
--
Michael