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Re: three reads to get 64 blocks with dfmrc=32

From: jaromir nemec <jaromir_at_db-nemec.com>
Date: Wed, 18 May 2005 00:02:43 +0200
Message-ID: <016e01c55b2c$2884af00$3c02a8c0@JARAWIN>


Hi Tim,

> I would guess that there is only room in those

> read buffers in each P00x process's PGA for sixty-one 16-Kb buffers

Exactly, I set the dfmrc to 64, so there are two reads per extent, 61 blocks and 2 blocks.

Lowering dfmrc to 10 there are 6 x 10 + 1 reads.

I varied pga_aggregate_target between 10M and 50M with no effect on this behavior.

I'll examine the influence of parallel_execution_message_size but this will take some preparation.

It is not really a big issue , but it is *not nice*.

Thanks anyway

Jaromir

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Received on Tue May 17 2005 - 18:10:50 CDT

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