On 2020-11-25 14:13, Fujii Masao wrote:
On 2020/11/24 23:14, Fujii Masao wrote:
On 2020/11/19 14:33, torikoshia wrote:
On 2020-11-18 11:35, Fujii Masao wrote:
Thanks for your comment!
On 2020/11/18 11:04, torikoshia wrote:
Hi,
AFAIU, when the planner statistics are updated, generic plans are
invalidated and PostgreSQL recreates. However, the manual doesn't
seem to explain it explicitly.
https://www.postgresql.org/docs/devel/sql-prepare.html
I guess this case is included in 'whenever database objects used in
the statement have definitional (DDL) changes undergone', but I
feel it's hard to infer.
Since updates of the statistics can often happen, how about
describing this case explicitly like an attached patch?
+1 to add that note.
- statement. Also, if the value of <xref
linkend="guc-search-path"/> changes
+ statement. For example, when the planner statistics of the
statement
+ are updated, <productname>PostgreSQL</productname> re-analyzes
and
+ re-plans the statement.
I don't think "For example," is necessary.
"planner statistics of the statement" sounds vague? Does the
statement
is re-analyzed and re-planned only when the planner statistics of
database
objects used in the statement are updated? If yes, we should
describe
that to make the note a bit more explicitly?
Yes. As far as I confirmed, updating statistics which are not used in
prepared statements doesn't trigger re-analyze and re-plan.
Since plan invalidations for DDL changes and statistcal changes are
caused
by PlanCacheRelCallback(Oid 'relid'), only the prepared statements
using
'relid' relation seem invalidated.> Attached updated patch.
Thanks for confirming that and updating the patch!
force re-analysis and re-planning of the statement before using it
whenever database objects used in the statement have undergone
definitional (DDL) changes since the previous use of the prepared
- statement. Also, if the value of <xref linkend="guc-search-path"/>
changes
+ statement. Similarly, whenever the planner statistics of database
+ objects used in the statement have updated, re-analysis and
re-planning
+ happen.
"been" should be added between "have" and "updated" in the above
"objects
used in the statement have updated"?
You're right.
I'm inclined to add "since the previous use of the prepared statement"
into
also the second description, to make it clear. But if we do that, it's
better
to merge the above two description into one, as follows?
whenever database objects used in the statement have undergone
- definitional (DDL) changes since the previous use of the prepared
+ definitional (DDL) changes or the planner statistics of them have
+ been updated since the previous use of the prepared
statement. Also, if the value of <xref linkend="guc-search-path"/>
changes
Thanks, it seems better.
Regards,
