This commit switches query jumbling so as prepared statement names are
treated as constants in DeallocateStmt. A boolean field is added to
DeallocateStmt to make a distinction between ALL and named prepared
statements, as "name" was used to make this difference before, NULL
meaning DEALLOCATE ALL.
Prior to this commit, DEALLOCATE was not tracked in pg_stat_statements,
for the reason that it was not possible to treat its name parameter as a
constant. Now that query jumbling applies to all the utility nodes,
this reason does not apply anymore.
Like 638d42a3c5, this can be a huge advantage for monitoring where
prepared statement names are randomly generated, preventing bloat in
pg_stat_statements. A couple of tests are added to track the new
behavior.
Author: Dagfinn Ilmari Mannsåker, Michael Paquier
Reviewed-by: Julien Rouhaud
Discussion: https://postgr.es/m/ZMhT9kNtJJsHw6jK@paquier.xyz
This relies on the "location" field added to TransactionStmt in 31de7e6,
now applied to the "gid" field used by 2PC commands. These commands are
now reported like:
COMMIT PREPARED $1
PREPARE TRANSACTION $1
ROLLBACK PREPARED $1
Applying constants for these commands is a huge advantage for workloads
that rely a lot on 2PC commands with different GIDs. Some tests are
added to track the new behavior.
Reviewed-by: Julien Rouhaud
Discussion: https://postgr.es/m/ZMhT9kNtJJsHw6jK@paquier.xyz
In pg_stat_statements, savepoint names now show up as constants with a
parameter symbol, using as base query string the one added as a new
entry to the PGSS hash table, leading to:
RELEASE $1
ROLLBACK TO $1
SAVEPOINT $1
Applying constants to these query parts is a huge advantage for
workloads that generate randomly savepoint points, like ORMs (Django is
at the origin of this patch). The ODBC driver is a second layer that
likes a lot savepoints, though it does not use a random naming pattern.
A "location" field is added to TransactionStmt, now set only for
savepoints. The savepoint name is ignored by the query jumbling. The
location can be extended to other query patterns, if required, like 2PC
commands. Some tests are added to pg_stat_statements for all the query
patterns supported by the parser.
ROLLBACK, ROLLBACK TO SAVEPOINT and ROLLBACK TRANSACTION TO SAVEPOINT
have the same Node representation, so all these are equivalents. The
same happens for RELEASE and RELEASE SAVEPOINT.
Author: Greg Sabino Mullane
Discussion: https://postgr.es/m/CAKAnmm+2s9PA4OaumwMJReWHk8qvJ_-g1WqxDRDAN1BSUfxyTw@mail.gmail.com
Applying normalization changes how the following query strings are
reflected in pg_stat_statements, by showing Const nodes with a
dollar-signed parameter as this is how such queries are structured
internally once parsed:
- DECLARE
- EXPLAIN
- CREATE MATERIALIZED VIEW
- CREATE TABLE AS
More normalization could be done in the future depending on the parts
where query jumbling is applied (like A_Const nodes?), the changes being
reflected in the regression tests in majority created in de2aca2. This
just allows the basics to work for utility queries using Const nodes.
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/Y+MRdEq9W9XVa2AB@paquier.xyz
As shaped, two DROP ROLE queries included in "user_activity" were
showing in the reports for "wal". The intention is to keep each test
isolated and independent, so this is incorrect. This commit adds some
calls to pg_stat_statements_reset() to clean up the statistics once each
test finishes, so as there are no risks of overlap in the reports for
individial scenarios.
The addition in "user_activity" fixes the output of "wal". The new
resets done in "level_tracking" and "utility" are added for consistency
with the rest, though they do not affect the stats generated in the
other tests.
Oversight in d0028e3.
Reported-by: Andrei Zubkov
Discussion: https://postgr.es/m/7beb722dd016bf54f1c78bfd6d44a684e28da624.camel@moonset.ru
This commit adds more coverage for utility statements so as it is
possible to track down all the effects of query normalization done for
all the queries that use either Const or A_Const nodes, which are the
nodes where normalization makes the most sense as they apply to
constants (well, most of the time, really).
This set of queries is extracted from an analysis done while looking at
full dumps of the regression database when applying different levels of
normalization to either Const or A_Const nodes for utilities, as of a
minimal set of these, for:
- All relkinds (CREATE, ALTER, DROP)
- Policies
- Cursors
- Triggers
- Types
- Rules
- Statistics
- CALL
- Transaction statements (isolation level, options)
- EXPLAIN
- COPY
Note that pg_stat_statements is not switched yet to show any
normalization for utilities, still it improves the default coverage of
the query jumbling code (not by as much as enabling query jumbling on
the main regression test suite, though):
- queryjumblefuncs.funcs.c: 36.8% => 48.5%
- queryjumblefuncs.switch.c: 33.2% => 43.1%
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/Y+MRdEq9W9XVa2AB@paquier.xyz
pg_stat_statements.sql acts as the main file for all the core tests of
the module, but things have become complicated to follow over the years
as some of the sub-scenarios tested in this file rely on assumptions
that come from completely different areas of it, like a GUC setup or a
relation created previously. For example, row tracking for CTAS/COPY
was looking at the number of plans, which was not necessary, or level
tracking was mixed with checks on planner counts.
This commit refactors the tests of pg_stat_statements, by moving test
cases out of pg_stat_statements.sql into their own file, as of:
- Planning-related tests in planning.sql, for [re]plan counts and
top-level handling. These depend on pg_stat_statements.track_planning.
- Utilities in utility.sql (pg_stat_statements.track_utility), that
includes now the tests for:
-- Row tracking for CTAS, CREATE MATERIALIZED VIEW, COPY.
-- Basic utility statements.
-- SET statements.
- Tracking level, depending on pg_stat_statements.track. This part has
been looking at scenarios with DO blocks, PL functions and SQL
functions.
pg_stat_statements.sql (still named the same for now) still includes
some checks for role-level tracking and WAL generation metrics, that
ought to become independent in the long term for clarity.
While on it, this switches the order of the attributes when querying
pg_stat_statements, the query field becoming last. This makes much
easier the tracking of changes related to normalization, as queries are
the only variable-length attributes queried (unaligned mode would be one
extra choice, but that reduces the checks on the other fields).
Test scenarios and their results match exactly with what was happening
before this commit in terms of calls, number of plans, number of rows,
cached data or level tracking, so this has no effect on the coverage in
terms of what is produced by the reports in the table
pg_stat_statements. A follow-up patch will extend more the tests of
pg_stat_statements around utilities, so this split creates a foundation
for this purpose, without complicating more pg_stat_statements.sql.
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/Y+MRdEq9W9XVa2AB@paquier.xyz
Michael Paquier