Re: Calculation of a shared memory

From: "Hiroshi Saito" <z-saito(at)guitar(dot)ocn(dot)ne(dot)jp>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Calculation of a shared memory
Date: 2007-11-02 03:15:25
Message-ID: 0bc301c81cfe$9ce67900$c601a8c0@HP22720319231
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Hi.

Thanks!

From: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
>> I think it is a permissible range. Thanks!
>
> Most of the remaining discrepancy is because you did not account for the
> per-shared-buffer management overhead. The table shows shared_buffers
> as costing 8300 bytes each, not 8192.

Oops, I did the misapprehension by the alteration of MB and kB.
This estimates the value secured more correctly.

40*(1800+270*64)= 763200
5*(700+270*64)= 89900
28MB*1024/8*8300= 29747200
64kB/8*8200= 65600
1000*70= 70000
179200*6= 1075200
700kB= 716800

Total :32527900
ipcs-m:32571392
-43492

Does this suit?

Regards,
Hiroshi Saito

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