On 2020/11/06 1:56, Mark Dilger wrote:
On Nov 5, 2020, at 8:20 AM, Fujii Masao <masao.fu...@oss.nttdata.com> wrote:
The patch that makes pg_stat_statements track the number of rows that
REFRESH MATERIALIZED VIEW command processes was proposed at [1].
When reviewing the patch, I just wondered why the completion tag output
for REFRESH MATERIALIZED VIEW doesn't include the row count. Is this
an intentional behavior? I've not found the past discussion about this yet.
Of 191 command tags, only 7 return the number of rows. See
src/include/tcop/cmdtaglist.h. REFRESH MATERIALIZED VIEW is similar to CREATE
MATERIALIZED VIEW and also CREATE TABLE AS, which also do not return the row
count.
Yes, so I was wondering if REFRESH MATERIALIZED VIEW also should use
CMDTAG_SELECT like CREATE MATERIALIZED VIEW does.
I think this behavior is historical, and preserved for compatibility.
Maybe true. The patch that I mentioned upthread tries to change
REFRESH MATERIALIZED VIEW so that it register the rowcount into
its query completion so that pg_stat_statements can track
the number of processed rows. But display_rowcount for
CMDTAG_REFRESH_MATERIALIZED_VIEW still should be false
in cmdtaglist.h to avoid the change of the completion tag output.
Regards,
--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION
