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Re: brininsert optimization opportunity

Tomas Vondra <tomas.vondra@enterprisedb.com>

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From: Tomas Vondra <tomas.vondra@enterprisedb.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>, Soumyadeep Chakraborty <soumyadeep2007@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, Ashwin Agrawal <ashwinstar@gmail.com>
Date: 2023-07-04T11:59:21Z
Lists: pgsql-hackers 

On 7/4/23 13:23, Alvaro Herrera wrote:
> On 2023-Jul-03, Soumyadeep Chakraborty wrote:
> 
>> My colleague, Ashwin, pointed out to me that brininsert's per-tuple init
>> of the revmap access struct can have non-trivial overhead.
>>
>> Turns out he is right. We are saving 24 bytes of memory per-call for
>> the access struct, and a bit on buffer/locking overhead, with the
>> attached patch.
> 
> Hmm, yeah, I remember being bit bothered by this repeated
> initialization.  Your patch looks reasonable to me.  I would set
> bistate->bs_rmAccess to NULL in the cleanup callback, just to be sure.
> Also, please add comments atop these two new functions, to explain what
> they are.
> 
> Nice results.
> 

Yeah. I wonder how much of that runtime is the generate_series(),
though. What's the speedup if that part is subtracted. It's guaranteed
to be even more significant, but by how much?

regards

-- 
Tomas Vondra
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add missing index_insert_cleanup calls

  2. Fix a couple typos in BRIN code

  3. Check if ii_AmCache is NULL in aminsertcleanup

  4. Use fipshash in brin_multi test

  5. Reuse BrinDesc and BrinRevmap in brininsert

  6. Consider fillfactor when estimating relation size

  7. Postpone some stuff out of ExecInitModifyTable.