Date: Mon, 5 Oct 2020 15:08:32 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: =?utf-8?B?5p2O5p2wKOaFjui/vSk=?= <adger.lj@alibaba-inc.com>,
	pgsql-hackers <pgsql-hackers@lists.postgresql.org>,
	=?utf-8?B?5pu+5paH5peMKOS5ieS7jik=?= <wenjing.zwj@alibaba-inc.com>,
	Alvaro Herrera <alvherre@2ndquadrant.com>
Subject: Re: =?utf-8?B?5Zue5aSN77yaaG8=?= =?utf-8?Q?w?= to create index
 concurrently on partitioned table
Message-ID: <20201005200832.GF17626@telsasoft.com>
References: <20200809234423.GH20473@telsasoft.com>
 <20200901055158.GH3511@paquier.xyz>
 <20200908023915.GD7158@telsasoft.com>
 <20200908043105.GE19261@paquier.xyz>
 <20200912001301.GQ18552@telsasoft.com>
 <20200912013239.GA8636@paquier.xyz>
 <20200914143102.GX18552@telsasoft.com>
 <20200924081103.GS28585@paquier.xyz>
 <20200926195655.GA13816@telsasoft.com>
 <20201005084627.GI1464@paquier.xyz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20201005084627.GI1464@paquier.xyz>
User-Agent: Mutt/1.9.4 (2018-02-28)
Precedence: bulk

On Mon, Oct 05, 2020 at 05:46:27PM +0900, Michael Paquier wrote:
> On Sat, Sep 26, 2020 at 02:56:55PM -0500, Justin Pryzby wrote:
> > Also, if a partitioned index is clustered, when we clear indisclustered for
> > other indexes, should we also propogate that to their parent indexes, if any ?
> 
> I am not sure what you mean here.  Each partition's cluster runs in
> its own individual transaction based on the patch you sent.  Are you
> suggesting to update indisclustered for the partitioned index of a
> partitioned table and all its parent partitioned in the same
> transaction, aka a transaction working on the partitioned table?

No, I mean that if a partition is no longer clustered on some index, then its
parent isn't clustered on that indexes parent, either.

It means that we might do N catalog updates for a partition heirarchy that's N
levels deep.  Normally, N=2, and we'd clear indisclustered for the index as
well as its parent.  This is not essential, though.

> >> 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".
> 
> Indeed, I did not know this property.

I think that's something we can apply for CIC/DIC, too.
It's not essential to avoid leaving an "invalid" or partial index if
interrupted.  It's only essential that a partial, partitioned index is not
"valid".

For DROP IND CONCURRENTLY, I wrote:

On Mon, Sep 14, 2020 at 09:31:03AM -0500, Justin Pryzby wrote:
> 2. Maybe the easiest way is to mark all indexes invalid and then drop all
> partitions (concurrently) and then the partitioned parent.  If interrupted,
> this would leave a parent index marked "invalid", and some child tables with no
> indexes.  I think this may be "ok".  The same thing is possible if a concurrent
> build is interrupted, right ?


-- 
Justin