Re: varlena beyond 1GB and matrix - Mailing list pgsql-hackers

From Tom Lane
Subject Re: varlena beyond 1GB and matrix
Date
Msg-id 3837.1481156181@sss.pgh.pa.us
Whole thread Raw
In response to Re: varlena beyond 1GB and matrix  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
I wrote:
> Maybe.  I think where KaiGai-san is trying to go with this is being
> able to turn an ExpandedObject (which could contain very large amounts
> of data) directly into a toast pointer or vice versa.  There's nothing
> really preventing a TOAST OID from having more than 1GB of data
> attached, and if you had a side channel like this you could transfer
> the data without ever having to form a larger-than-1GB tuple.

BTW, you could certainly imagine attaching such infrastructure for
direct-to-TOAST-table I/O to ExpandedObjects today, independently
of any ambitions about larger-than-1GB values.  I'm not entirely sure
how often it would get exercised, which is the key subtext of what
I wrote before, but it's clearly a possible optimization of what
we do now.
        regards, tom lane



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