Re: extensible external toast tuple support & snappy prototype - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: extensible external toast tuple support & snappy prototype
Date
Msg-id 20130607161648.GB7200@tamriel.snowman.net
Whole thread Raw
In response to Re: extensible external toast tuple support & snappy prototype  (Andres Freund <andres@2ndquadrant.com>)
Responses Re: extensible external toast tuple support & snappy prototype
List pgsql-hackers
* Andres Freund (andres@2ndquadrant.com) wrote:
> Currently on a little endian system the pglz header contains the length
> in the first four bytes as:
> [dddddddd][dddddddd][dddddddd][xxdddddd]
> Where dd are valid length bits for pglz and xx are the two bits which
> are always zero since we only ever store up to 1GB. We can redefine 'xx'
> to mean whatever we want but we cannot change it's place.

I'm not thrilled with the idea of using those 2 bits from the length
integer.  I understand the point of it and that we'd be able to have
binary compatibility from it but is it necessary to track at the
per-tuple level..?  What about possibly supporting >1GB objects at some
point (yes, I know there's a lot of other issues there, but still).
We've also got complexity around the size of the length integer already.

Anyway, just not 100% sure that we really want to use these bits for
this.
Thanks,
    Stephen

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