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Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap [Review] - Mailing list pgsql-hackers

From Jameison Martin
Subject Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap [Review]
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Msg-id 1358888408.24671.YahooMailNeo@web160103.mail.bf1.yahoo.com
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Responses Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap [Review]
Re: Re: patch submission: truncate trailing nulls from heap rows to reduce the size of the null bitmap [Review]
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Sorry for the late response, I just happened to see this yesterday.

Running a general benchmark against the patch as Keven suggests is a good idea. 

Amit, can you supply the actual values you saw when running pgbench (the 3 values for each run)? I'd like to verify that the 1% difference isn't due to some file system/OS variability (would be interested in what the stdev is for the values). Also, do you happen to have some information about the hardware you ran on?

Meanwhile, I'll rerun on my end to see if I can reproduce your numbers. And I'll get a run of pgbench with minimal I/O since that can induce a lot of variability.

Also, Amit, I want to thank you for all your work on this patch, it is greatly appreciated.

Thanks

-Jamie


On Monday, December 24, 2012 7:58 PM Kevin Grittner wrote:

Simon Riggs wrote:


Not really sure about the 100s of columns use case.

But showing gain in useful places in these more common cases wins
my vote.

Thanks for testing. Barring objections, will commit.

Do we have any results on just a plain, old stock pgbench run, with
the default table definitions?

That would be a reassuring complement to the other tests.

Sever Configuration: 
The database cluster will be initialized with locales   COLLATE:  C   CTYPE:    C   MESSAGES: en_US.UTF-8   MONETARY: en_US.UTF-8   NUMERIC:  en_US.UTF-8   TIME:     en_US.UTF-8 

shared_buffers = 1GB 
checkpoint_segments = 255   
checkpoint_timeout = 15min   

pgbench: 
transaction type: TPC-B (sort of) 
scaling factor: 75 
query mode: simple 
number of clients: 8 
number of threads: 8 
duration: 600 s 

Performance: Average of 3 runs of pgbench in tps 
9.3devel  |  with trailing null patch 
----------+-------------------------- 
578.9872  |   573.4980

With Regards,
Amit Kapila.

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