From: | Teodor Sigaev <teodor(at)sigaev(dot)ru> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | pgsql-hackers(at)postgreSQL(dot)org |
Subject: | Re: Some other things about contrib/bloom and generic_xlog.c |
Date: | 2016-04-11 14:22:48 |
Message-ID: | 570BB338.5000000@sigaev.ru |
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Thread: | |
Lists: | pgsql-hackers |
> mainline XLOG replay. Shouldn't generic_xlog.c take the same trouble?
Yes, it should. Alexander now works on it.
>
> 2. Unless I'm missing something, contrib/bloom is making no effort
> to ensure that bloom index pages can be distinguished from other pages
> by pg_filedump. That's fine if your expectation is that bloom will always
> be a toy with no use in production; but otherwise, not so much. You need
> to make sure that the last two bytes of the page special space contain a
> uniquely identifiable code; compare spgist_page_id in SPGiST indexes.
Now contrib/bloom is a canonical example how to implement yourown index and how
to use generic WAL interface. And it is an useful toy: in some cases it could
help in production system, patch attached. I'm a little dissatisfied with patch
because I had to add unused field to BloomPageOpaqueData, in opposite case size
of BloomPageOpaqueData struct equals 6 bytes but special size is MAXALIGNED, so,
last two bytes will be unused. If unused field is not a problem, I will push
this patch.
--
Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru
WWW: http://www.sigaev.ru/
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