Re: Requesting clarification on Vacuuming/Freezing behaviour - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Requesting clarification on Vacuuming/Freezing behaviour
Date
Msg-id 47662EAD.4080405@enterprisedb.com
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In response to Requesting clarification on Vacuuming/Freezing behaviour  ("Gokulakannan Somasundaram" <gokul007@gmail.com>)
Responses Re: Requesting clarification on Vacuuming/Freezing behaviour  ("Gokulakannan Somasundaram" <gokul007@gmail.com>)
List pgsql-hackers
Gokulakannan Somasundaram wrote:
> a) When i was looking at the code for freezing heap tuples, i found out the
> following. While freezing we log the complete block(not just the tuples we
> froze).
> b) Again after removing the dead tuples and fragmentation, we log the
> complete block.

Umm, no we don't. In log_heap_freeze, we log an array of offsets, of 
those tuples that were frozen.

Perhaps you're been confused by full page writes? If a block hasn't been 
modified by last checkpoint, then we do log the whole page for any 
operation, including vacuuming and freezing. (except setting hint bits).

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com


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