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Re: How to generate specific WAL records?

From: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
To: Koichi Suzuki <koichi(dot)szk(at)gmail(dot)com>, f(at)alvh(dot)no-ip(dot)org
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: How to generate specific WAL records?
Date: 2010-04-13 22:00:20
Message-ID: 20100413220020.GJ2990@alvh.no-ip.org (view raw or flat)
Thread:
Lists: pgsql-hackers
Koichi Suzuki escribió:
> Hi,
> 
> Does anyone know how to generate the following WAL records from psql?
> 
> I'm now fixing pg_lesslog, which I reported a bug.   Now code is
> almost okay and I'd like to add test tools to show pg_lesslog can
> handle all the WAL record correctly.
> 
> XLOG_MULTIXACT_ZERO_OFF_PAGE
> XLOG_MULTIXACT_ZERO_MEM_PAGE
> XLOG_MULTIXACT_CREATE_ID

For these, you need to do SELECT FOR SHARE of a tuple in more than one
concurrent session.

I think HEAP_LOCK is SELECT FOR UPDATE.


> XLOG_BTREE_DELETE_PAGE
> XLOG_BTREE_DELETE_PAGE_META
> XLOG_BTREE_DELETE_PAGE_HALF

These are caused during vacuum of a btree.  Create an index, populate
it, then remove all items.  Then vacuum twice.

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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