Re: Question regarding the database page layout. - Mailing list pgsql-hackers

From Gregory Stark
Subject Re: Question regarding the database page layout.
Date
Msg-id 878wv3ucog.fsf@oxford.xeocode.com
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In response to Question regarding the database page layout.  ("Ryan Bradetich" <rbradetich@gmail.com>)
Responses Re: Question regarding the database page layout.  ("Ryan Bradetich" <rbradetich@gmail.com>)
Re: Question regarding the database page layout.  ("Ryan Bradetich" <rbradetich@gmail.com>)
List pgsql-hackers
"Ryan Bradetich" <rbradetich@gmail.com> writes:

> After a cursory glance at the HeapTupleHeaderData structure, it appears it
> could be aligned with INTALIGN instead of MAXALIGN. The one structure I was
> worried about was the 6 byte t_ctid structure. The comments in
> src/include/storage/itemptr.h file indicate the ItemPointerData structure is
> composed of 3 int16 fields. So everthing in the HeapTupleHeaderData
> structure is 32-bits or less.

Sure, but the tuple itself could contain something with double alignment. If
you have a bigint or double in the tuple then heap_form_tuple needs to know
where to put it so it ends up at right alignment.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com Ask me about EnterpriseDB's Slony Replication
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