Re: Reading deleted records - PageHeader v3 - Mailing list pgsql-hackers

From Jonathan Bond-Caron
Subject Re: Reading deleted records - PageHeader v3
Date
Msg-id 000c01caa800$e5e83ff0$b1b8bfd0$@com
Whole thread Raw
In response to Re: Reading deleted records - PageHeader v3  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Sat Feb 6 01:20 AM, Tom Lane wrote:
> "Jonathan Bond-Caron" <jbondc@gmail.com> writes:
> > I think part of my problem is I haven't really understood what 'Then 
> > make sure you have the right alignment' means.
> 
> > My approach currently is:
> 
> > After reading HeapTupleHeaderData (23 bytes), I advance another 4 
> > bytes
> > (hoff) and try to read a 32 bit integer (first attribute).
> 
> No.  First you start at the tuple beginning plus the number of bytes 
> indicated by hoff (which should be at least 24).  

Thanks, much appreciated!

I was reading HeapTupleHeaderData as 23 bytes but it's 27 bytes in
access/htup.h?rev=1.87. 

The hoff now makes sense with a 28 bytes value and I can start to read the
user data.







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