Horton

Re: Experimenting with hash tables inside pg_dump

Nathan Bossart <bossartn@amazon.com>

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From: "Bossart, Nathan" <bossartn@amazon.com>
To: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2021-10-21T23:59:57Z
Lists: pgsql-hackers 
On 10/21/21, 4:14 PM, "Bossart, Nathan" <bossartn@amazon.com> wrote:
> On 10/21/21, 3:29 PM, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:
>> (b) I couldn't measure any change in performance at all.  I tried
>> it on the regression database and on a toy DB with 10000 simple
>> tables.  Maybe on a really large DB you'd notice some difference,
>> but I'm not very optimistic now.
>
> I wonder how many tables you'd need to start seeing a difference.
> There are certainly databases out there with many more than 10,000
> tables.  I'll look into this...

Well, I tested with 200,000 tables and saw no difference with this.

Nathan

Commits

  1. In pg_dump, use simplehash.h to look up dumpable objects by OID.

  2. Fix frontend version of sh_error() in simplehash.h.