Re: MultiXacts & WAL - Mailing list pgsql-hackers

From paolo romano
Subject Re: MultiXacts & WAL
Date
Msg-id 20060617173718.63055.qmail@web27809.mail.ukl.yahoo.com
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In response to Re: MultiXacts & WAL  (Heikki Linnakangas <hlinnaka@iki.fi>)
Responses Re: MultiXacts & WAL  (Heikki Linnakangas <hlinnaka@iki.fi>)
Re: MultiXacts & WAL  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
<blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br
/>InPostgreSQL, shared locks are not taken when just reading data. They're <br />used to enforce foreign key
constraints.When inserting a row to a table <br />with a foreign key, the row in the parent table is locked to <br
/>keepanother transaction from deleting it. It's not safe to release the <br />lock before end of transaction.<br /><br
/><br/></blockquote>Releasing shared locks (whether used for plain reading or enforcing foreign keys) before
transactionend would be clearly wrong.<br />The original point I was moving is if there were any concrete reason (which
stillI can't see) to require Multixacts recoverability (by means of logging). <br />Concerning the prepare state of two
phasecommit, as I was pointing out in my previous post, shared locks can safely be released once a transaction gets
precommitted,hence they do not have to be made durable.<br /><br /><br /><br /><p> Chiacchiera con i tuoi amici in
temporeale! <br /> http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com  

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