Re: Lazy Snapshots - Mailing list pgsql-hackers

From Gokulakannan Somasundaram
Subject Re: Lazy Snapshots
Date
Msg-id 9362e74e0908212118v669d67c3l12fa1c9840562276@mail.gmail.com
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In response to Re: Lazy Snapshots  ("simon@2ndquadrant.com" <simon@2ndquadrant.com>)
Responses Re: Lazy Snapshots  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Hi,<br />   I have given some thought in this direction. I am just providing my idea.<br /><br />a) Have a structure
similarto commit log, which should also store, transaction id at which the transaction got committed. Every
transaction,after committing should update the transaction id at which the commit has happened<br /> b) All the
transactions-when it starts should have two figures - xmin and also a transaction id after which nothing has got
committed<br/>c) So whenever it sees the records, which are not inside the window, it can make decision by itself. <br
/>       i) The ones below xmin and committed are visible<br />       ii) the ones after xmax and committed are not
visible<br/>       iii) When its something in between, then check the time at which the commit happened in the
structureand make the decision.<br /><br />Ideally, it would be better to change the structure of commit log itself.
Butmaintaining an another structure also would help.<br /><br />Thanks,<br />Gokul.<br /> 

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