Thanks Tom. This showed up in a regression test of ours that built the test data using generate_series, so it's not a critical production issue or anything, just a surprise change in behaviour.
P.
On Wed, May 24, 2017 at 10:28 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Paul Ramsey <pramsey@cleverelephant.ca> writes: > The behaviour of generate_series seems to have changed a little, at least > in conjunction w/ CTEs.
What's changed is the behavior of multiple SRFs in a SELECT's targetlist, cf
While moving SRF evaluation to ProjectSet would allow to retain the old "least common multiple" behavior when multiple SRFs are present in one targetlist (i.e. continue returning rows until all SRFs are at the end of their input at the same time), we decided to instead only return rows till all SRFs are exhausted, returning NULL for already exhausted ones. We deemed the previous behavior to be too confusing, unexpected and actually not particularly useful.
I see the current v10 release notes have failed miserably at documenting this :-(. Will try to improve that.