From: | "Syed, Rahila" <Rahila(dot)Syed(at)nttdata(dot)com> |
---|---|
To: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
Cc: | Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, PostgreSQL mailing lists <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [REVIEW] Re: Compression of full-page-writes |
Date: | 2015-02-11 14:03:00 |
Message-ID: | C3C878A2070C994B9AE61077D46C3846589AD3DB@MAIL703.KDS.KEANE.COM |
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Thread: | |
Lists: | pgsql-hackers |
>IMO, we should add details about how this new field is used in the comments on top of XLogRecordBlockImageHeader, meaning that when a page hole is present we use the compression info structure and when there is no hole, we are sure that the FPW raw length is BLCKSZ meaning that the two bytes of the CompressionInfo stuff is unnecessary.
This comment is included in the patch attached.
> For correctness with_hole should be set even for uncompressed pages. I think that we should as well use it for sanity checks in xlogreader.c when decoding records.
This change is made in the attached patch. Following sanity checks have been added in xlogreader.c
if (!(blk->with_hole) && blk->hole_offset != 0 || blk->with_hole && blk->hole_offset <= 0))
if (blk->with_hole && blk->bkp_len >= BLCKSZ)
if (!(blk->with_hole) && blk->bkp_len != BLCKSZ)
Thank you,
Rahila Syed
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Attachment | Content-Type | Size |
---|---|---|
Support-compression-for-full-page-writes-in-WAL_v18.patch | application/octet-stream | 24.8 KB |
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