Horton

Re: Speed up Clog Access by increasing CLOG buffers

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Thom Brown <thom@linux.com>, Simon Riggs <simon@2ndquadrant.com>, Jesper Pedersen <jesper.pedersen@redhat.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2016-02-21T06:54:18Z
Lists: pgsql-hackers 
On Sun, Feb 21, 2016 at 12:02 PM, Robert Haas <robertmhaas@gmail.com> wrote:

> On Sun, Feb 21, 2016 at 10:27 AM, Amit Kapila <amit.kapila16@gmail.com>
> wrote:
>
>>
>> Client_Count/Patch_Ver 1 64 128 256
>> HEAD(481725c0) 963 28145 28593 26447
>> Patch-1 938 28152 31703 29402
>>
>>
>> We can see 10~11% performance improvement as observed
>> previously.  You might see 0.02% performance difference with
>> patch as regression, but that is just a run-to-run variation.
>>
>
> Don't the single-client numbers show about a 3% regresssion?  Surely not
> 0.02%.
>


Sorry, you are right, it is ~2.66%, but in read-write pgbench tests, I
could see such fluctuation.  Also patch doesn't change single-client
case.  However, if you still feel that there could be impact by patch,
I can re-run the single client case once again with different combinations
like first with HEAD and then patch and vice versa.


With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com

Commits

  1. Use group updates when setting transaction status in clog.

  2. Improve 64bit atomics support.

  3. Add ProcArrayGroupUpdate wait event.

  4. Make the different Unix-y semaphore implementations ABI-compatible.

  5. Fix broken ALTER INDEX documentation

  6. Code and docs review for commit 3187d6de0e5a9e805b27c48437897e8c39071d45.

  7. Partition the freelist for shared dynahash tables.

  8. Correct StartupSUBTRANS for page wraparound

  9. Make idle backends exit if the postmaster dies.

  10. contrib/sslinfo: add ssl_extension_info SRF

  11. Reduce ProcArrayLock contention by removing backends in batches.

  12. Fix `make installcheck` for serializable transactions.

  13. Lockless StrategyGetBuffer clock sweep hot path.

  14. Reduce sinval synchronization overhead.