CREATE INDEX CONCURRENTLY on partitioned index

Forking this thread, since the existing CFs have been closed.
https://www.postgresql.org/message-id/flat/20200914143102.GX18552%40telsasoft.com#58b1056488451f8594b0f0ba40996afd

The strategy is to create catalog entries for all tables with indisvalid=false,
and then process them like REINDEX CONCURRENTLY.  If it's interrupted, it
leaves INVALID indexes, which can be cleaned up with DROP or REINDEX, same as
CIC on a plain table.

On Sat, Aug 08, 2020 at 01:37:44AM -0500, Justin Pryzby wrote:
> On Mon, Jun 15, 2020 at 09:37:42PM +0900, Michael Paquier wrote:
> > On Mon, Jun 15, 2020 at 08:15:05PM +0800, 李杰(慎追) wrote:
> > > As shown above, an error occurred while creating an index in the second partition. 
> > > It can be clearly seen that the index of the partitioned table is invalid 
> > > and the index of the first partition is normal, the second partition is invalid, 
> > > and the Third Partition index does not exist at all.
> > 
> > That's a problem.  I really think that we should make the steps of the
> > concurrent operation consistent across all relations, meaning that all
> > the indexes should be created as invalid for all the parts of the
> > partition tree, including partitioned tables as well as their
> > partitions, in the same transaction.  Then a second new transaction
> > gets used for the index build, followed by a third one for the
> > validation that switches the indexes to become valid.
> 
> Note that the mentioned problem wasn't serious: there was missing index on
> child table, therefor the parent index was invalid, as intended.  However I
> agree that it's not nice that the command can fail so easily and leave behind
> some indexes created successfully and some failed some not created at all.
> 
> But I took your advice initially creating invalid inds.
...
> That gave me the idea to layer CIC on top of Reindex, since I think it does
> exactly what's needed.

On Sat, Sep 26, 2020 at 02:56:55PM -0500, Justin Pryzby wrote:
> On Thu, Sep 24, 2020 at 05:11:03PM +0900, Michael Paquier wrote:
> > It would be good also to check if
> > we have a partition index tree that maps partially with a partition
> > table tree (aka no all table partitions have a partition index), where
> > these don't get clustered because there is no index to work on.
> 
> This should not happen, since a incomplete partitioned index is "invalid".

-- 
Justin