Re: HOT patch - version 14

"Gregory Stark" <stark(at)enterprisedb(dot)com> writes:

> "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
>
>> "Pavan Deolasee" <pavan(dot)deolasee(at)gmail(dot)com> writes:
>>> Please see the version 14 of HOT patch attached.
>>
>> I expected to find either a large new README, or some pretty substantial
>> additions to existing README files, to document how this all works.
>> The comments included do not represent nearly enough documentation.
>
> The Heikki and I posted a two-part README of sorts:

Er, editing error there. Has a ring to it though.

> http://archives.postgresql.org/pgsql-patches/2007-07/msg00142.php
> http://archives.postgresql.org/pgsql-patches/2007-07/msg00360.php
...
>> I also don't think I believe the reasoning for not indexing
>> DELETE_IN_PROGRESS hot-updated tuples: what if the index completion commits,
>> but the concurrent delete rolls back? Then you've got a valid tuple that's
>> not in the index.
>
> You're talking about the concurrent index build case? Wouldn't the second pass
> pick up that tuple? I have to look back at it to see for sure.

Sorry, that's misguided. The concurrent index build uses snapshots now so it
can't see DELETE_IN_PROGRESS. And the non-concurrent index build has an lock
so it ought to be back to the way it was before I messed with it where there
was an assert against finding *_IN_PROGRESS (except as Pavan points out in the
same transaction).

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com