Re: fast defaults in heap_getattr vs heap_deform_tuple

Him

On 2019-02-01 14:49:05 -0800, Andres Freund wrote:
> +#ifdef IAM_THE_WRONG_FIX
> if (HeapTupleHeaderGetNatts(tuple.t_data) < relation->rd_att->natts)
> result = heap_expand_tuple(&tuple, relation->rd_att);
> else
> result = heap_copytuple(&tuple);
> +#else
> + result = heap_copytuple(&tuple);
> +#endif

This was added in

commit 7636e5c60fea83a9f3cd2ad278c0819b98941c74
Author: Andrew Dunstan <andrew(at)dunslane(dot)net>
Date: 2018-09-24 16:11:24 -0400

Fast default trigger and expand_tuple fixes

Ensure that triggers get properly filled in tuples for the OLD value.
Also fix the logic of detecting missing null values. The previous logic
failed to detect a missing null column before the first missing column
with a default. Fixing this has simplified the logic a bit.

Regression tests are added to test changes. This should ensure better
coverage of expand_tuple().

Original bug reports, and some code and test scripts from Tomas Vondra

Backpatch to release 11.

Unfortunately the commit doesn't reference the discussion. That appears
to have been at
https://postgr.es/m/224e4807-395d-9fc5-2934-d5f85130f1f0%402ndQuadrant.com

Greetings,

Andres Freund