Re: [REVIEW] Re: Compression of full-page-writes

Hello ,

>I've not read this logic yet, but ISTM there is a bug in that new WAL format because I got the following error and the startup process could not replay any WAL records when I set up replication and enabled wal_compression.

>LOG: record with invalid length at 0/30000B0
>LOG: record with invalid length at 0/3000518
>LOG: Invalid block length in record 0/30005A0
>LOG: Invalid block length in record 0/3000D60 ...

Please fine attached patch which replays WAL records.

Thank you,
Rahila Syed

-----Original Message-----
From: pgsql-hackers-owner(at)postgresql(dot)org [mailto:pgsql-hackers-owner(at)postgresql(dot)org] On Behalf Of Fujii Masao
Sent: Monday, February 23, 2015 5:52 PM
To: Rahila Syed
Cc: PostgreSQL-development; Andres Freund; Michael Paquier
Subject: Re: [HACKERS] [REVIEW] Re: Compression of full-page-writes

On Mon, Feb 23, 2015 at 5:28 PM, Rahila Syed <rahilasyed90(at)gmail(dot)com> wrote:
> Hello,
>
> Attached is a patch which has following changes,
>
> As suggested above block ID in xlog structs has been replaced by chunk ID.
> Chunk ID is used to distinguish between different types of xlog record
> fragments.
> Like,
> XLR_CHUNK_ID_DATA_SHORT
> XLR_CHUNK_ID_DATA_LONG
> XLR_CHUNK_BKP_COMPRESSED
> XLR_CHUNK_BKP_WITH_HOLE
>
> In block references, block ID follows the chunk ID. Here block ID
> retains its functionality.
> This approach increases data by 1 byte for each block reference in an
> xlog record. This approach separates ID referring different fragments
> of xlog record from the actual block ID which is used to refer block
> references in xlog record.

I've not read this logic yet, but ISTM there is a bug in that new WAL format because I got the following error and the startup process could not replay any WAL records when I set up replication and enabled wal_compression.

LOG: record with invalid length at 0/30000B0
LOG: record with invalid length at 0/3000518
LOG: Invalid block length in record 0/30005A0
LOG: Invalid block length in record 0/3000D60 ...

Regards,

--
Fujii Masao

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