Re: [HACKERS] Challenges preventing us moving to 64 bit transactionid (XID)? - Mailing list pgsql-hackers

From Ildar Musin
Subject Re: [HACKERS] Challenges preventing us moving to 64 bit transactionid (XID)?
Date
Msg-id a7374d4a-e463-3c86-4f56-c08d5d5d6aa9@postgrespro.ru
Whole thread Raw
In response to Re: [HACKERS] Challenges preventing us moving to 64 bit transactionid (XID)?  (Alexander Korotkov <a.korotkov@postgrespro.ru>)
Responses Re: [HACKERS] Challenges preventing us moving to 64 bit transactionid (XID)?  (Alexander Korotkov <a.korotkov@postgrespro.ru>)
List pgsql-hackers
Hi Alexander,

On 22.06.2017 18:36, Alexander Korotkov wrote:
> On Wed, Jun 7, 2017 at 11:33 AM, Alexander Korotkov
> <a.korotkov@postgrespro.ru <mailto:a.korotkov@postgrespro.ru>> wrote:

> 0002-heap-page-special-1.patch
> Putting xid and multixact bases into PageHeaderData would take extra 16
> bytes on index pages too.  That would be waste of space for indexes.
> This is why I decided to put bases into special area of heap pages.
> This patch adds special area for heap pages contaning prune xid and
> magic number.  Magic number is different for regular heap page and
> sequence page.

We've discussed it earlier but it worth mentioning here too. You have 
pd_prune_xid of type TransactionId which is treated elsewhere as 
ShortTransactionId (see HeapPageGetPruneXid() and HeapPageSetPruneXid()) 
and hence introduces redundant 4 bytes. Could you please fix it?

-- 
Ildar Musin
i.musin@postgrespro.ru



pgsql-hackers by date:

Previous
From: Amit Kapila
Date:
Subject: Re: [HACKERS] WIP: long transactions on hot standby feedback replica/ proof of concept
Next
From: Nikolay Shaplov
Date:
Subject: Re: [HACKERS] [PATCH] Move all am-related reloption code into src/backend/access/[am-name] and get rid of relopt_kind for custom AM