Re: A thought on Index Organized Tables - Mailing list pgsql-hackers

From Gokulakannan Somasundaram
Subject Re: A thought on Index Organized Tables
Date
Msg-id 9362e74e1002272202k3b88d9f8yeb9e1eaeab93116b@mail.gmail.com
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In response to Re: A thought on Index Organized Tables  (Gokulakannan Somasundaram <gokul007@gmail.com>)
Responses Re: A thought on Index Organized Tables
Re: A thought on Index Organized Tables
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If i have got over excited in the previous update, please ignore that.<br /><br />a) We are already going from table to
indexto do unique checks. This is the same thing, which we will do to go and update the snapshot in the indexes.  <br
/>b) The way, it should work would be to have a check on whether the operator is broken / function is volatile and put
theonus on the user to make sure that they are updated correctly. <br />c) In the ItemId, instead of removing the size
fieldcompletely, we can store the size as size/4(since it is MaxAligned). This will save us 2 bits. In index we only
need13 bits to store the complete size in the tuple, but we use 15 bits in the iid, so again we can have two more bit
savingsthere. That's sufficient for us to express the hint fields in a index. I think Karl's way of expressing it
requiresonly one bit, which looks very efficient. So we can check the hint bits from the iid itself.<br /><br />So just
witha addition of 8 bytes per tuple, we can have the snapshot stored with the index. Can someone please comment on
this?<br/><br />Thanks,<br />Gokul.<br /><br /><br /> 

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