On Tue, 21 May 2002 11:53:04 -0400, Tom Lane <tgl@sss.pgh.pa.us>
wrote:
>The system tables that have OIDs will certainly continue to have OIDs.
That's clear. I should have written: "... rip out oids from tuple
headers of system tables."
>Ugh. While certainly we should have been using accessor
>macros for that, I'm not sure I want to try to change it.
I already did this for xmin, xmax, cmin, cmax, and xvac (see my patch
posted 2002-05-12).
>If OID is made to be the last fixed-offset field, instead of the first,
That would introduce some padding.
>then this approach would be fairly workable. Actually I'd still use
>just one struct definition, but do offsetof() calculations to decide
>where the null-bitmap starts.
... and for calculating the tuple header size.
>> Decouple on-disk format from in-memory structures, use
>> HeapTupleHeaderPack() and HeapTupleHeaderUnpack() to store/extract
>> header data to/from disk buffers. Concurrency?
>
>Inefficient,
Just to be sure: You mean the CPU cycles wasted by Pack() and
Unpack()?
>I'd be afraid to use a conversion-in-place tool for this sort of thing.
Me too. No, not in place! I thought of a filter reading an old
format data file, one page at a time, and writing a new format data
file. This would work as long as the conversions don't cause page
overflow.
No comment on a planned 7.3 timeframe? :-(
ServusManfred
