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Add generic_plans and custom_plans fields into pg_prepared_statements.

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There was no easy way to find how many times generic and custom plans
have been executed for a prepared statement. This commit exposes those
numbers of times in pg_prepared_statements view.

Author: Atsushi Torikoshi, Kyotaro Horiguchi
Reviewed-by: Tatsuro Yamada, Masahiro Ikeda, Fujii Masao
Discussion: https://postgr.es/m/CACZ0uYHZ4M=NZpofH6JuPHeX=__5xcDELF8hT8_2T+R55w4RQw@mail.gmail.com
pull/55/head
Fujii Masao 5 years ago
parent 044dc7b964
commit d05b172a76
8 changed files with 105 additions and 16 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 18
      doc/src/sgml/catalogs.sgml
  2. 15
      src/backend/commands/prepare.c
  3. 17
      src/backend/utils/cache/plancache.c
  4. 6
      src/include/catalog/pg_proc.dat
  5. 3
      src/include/utils/plancache.h
  6. 43
      src/test/regress/expected/plancache.out
  7. 6
      src/test/regress/expected/rules.out
  8. 13
      src/test/regress/sql/plancache.sql

18
doc/src/sgml/catalogs.sgml
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@ -10841,6 +10841,24 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
frontend/backend protocol
</para></entry>
</row>
<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>generic_plans</structfield> <type>int8</type>
</para>
<para>
Number of times generic plan was chosen
</para></entry>
</row>
<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>custom_plans</structfield> <type>int8</type>
</para>
<para>
Number of times custom plan was chosen
</para></entry>
</row>
</tbody>
</tgroup>
</table>

15
src/backend/commands/prepare.c
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@ -694,7 +694,8 @@ ExplainExecuteQuery(ExecuteStmt *execstmt, IntoClause *into, ExplainState *es,
/*
* This set returning function reads all the prepared statements and
* returns a set of (name, statement, prepare_time, param_types, from_sql).
* returns a set of (name, statement, prepare_time, param_types, from_sql,
* generic_plans, custom_plans).
*/
Datum
pg_prepared_statement(PG_FUNCTION_ARGS)
@ -723,7 +724,7 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
* build tupdesc for result tuples. This must match the definition of the
* pg_prepared_statements view in system_views.sql
*/
tupdesc = CreateTemplateTupleDesc(5);
tupdesc = CreateTemplateTupleDesc(7);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "name",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "statement",
@ -734,6 +735,10 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
REGTYPEARRAYOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 5, "from_sql",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 6, "generic_plans",
INT8OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 7, "custom_plans",
INT8OID, -1, 0);
/*
* We put all the tuples into a tuplestore in one scan of the hashtable.
@ -755,8 +760,8 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
hash_seq_init(&hash_seq, prepared_queries);
while ((prep_stmt = hash_seq_search(&hash_seq)) != NULL)
{
Datum values[5];
bool nulls[5];
Datum values[7];
bool nulls[7];
MemSet(nulls, 0, sizeof(nulls));
@ -766,6 +771,8 @@ pg_prepared_statement(PG_FUNCTION_ARGS)
values[3] = build_regtype_array(prep_stmt->plansource->param_types,
prep_stmt->plansource->num_params);
values[4] = BoolGetDatum(prep_stmt->from_sql);
values[5] = Int64GetDatumFast(prep_stmt->plansource->num_generic_plans);
values[6] = Int64GetDatumFast(prep_stmt->plansource->num_custom_plans);
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
}

17
src/backend/utils/cache/plancache.c vendored
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@ -218,6 +218,7 @@ CreateCachedPlan(RawStmt *raw_parse_tree,
plansource->generation = 0;
plansource->generic_cost = -1;
plansource->total_custom_cost = 0;
plansource->num_generic_plans = 0;
plansource->num_custom_plans = 0;
MemoryContextSwitchTo(oldcxt);
@ -285,6 +286,7 @@ CreateOneShotCachedPlan(RawStmt *raw_parse_tree,
plansource->generation = 0;
plansource->generic_cost = -1;
plansource->total_custom_cost = 0;
plansource->num_generic_plans = 0;
plansource->num_custom_plans = 0;
return plansource;
@ -1213,12 +1215,14 @@ GetCachedPlan(CachedPlanSource *plansource, ParamListInfo boundParams,
{
/* Build a custom plan */
plan = BuildCachedPlan(plansource, qlist, boundParams, queryEnv);
/* Accumulate total costs of custom plans, but 'ware overflow */
if (plansource->num_custom_plans < INT_MAX)
{
plansource->total_custom_cost += cached_plan_cost(plan, true);
plansource->num_custom_plans++;
}
/* Accumulate total costs of custom plans */
plansource->total_custom_cost += cached_plan_cost(plan, true);
plansource->num_custom_plans++;
}
else
{
plansource->num_generic_plans++;
}
Assert(plan != NULL);
@ -1574,6 +1578,7 @@ CopyCachedPlan(CachedPlanSource *plansource)
/* We may as well copy any acquired cost knowledge */
newsource->generic_cost = plansource->generic_cost;
newsource->total_custom_cost = plansource->total_custom_cost;
newsource->num_generic_plans = plansource->num_generic_plans;
newsource->num_custom_plans = plansource->num_custom_plans;
MemoryContextSwitchTo(oldcxt);

6
src/include/catalog/pg_proc.dat
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@ -7755,9 +7755,9 @@
{ oid => '2510', descr => 'get the prepared statements for this session',
proname => 'pg_prepared_statement', prorows => '1000', proretset => 't',
provolatile => 's', proparallel => 'r', prorettype => 'record',
proargtypes => '', proallargtypes => '{text,text,timestamptz,_regtype,bool}',
proargmodes => '{o,o,o,o,o}',
proargnames => '{name,statement,prepare_time,parameter_types,from_sql}',
proargtypes => '', proallargtypes => '{text,text,timestamptz,_regtype,bool,int8,int8}',
proargmodes => '{o,o,o,o,o,o,o}',
proargnames => '{name,statement,prepare_time,parameter_types,from_sql,generic_plans,custom_plans}',
prosrc => 'pg_prepared_statement' },
{ oid => '2511', descr => 'get the open cursors for this session',
proname => 'pg_cursor', prorows => '1000', proretset => 't',

3
src/include/utils/plancache.h
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@ -130,7 +130,8 @@ typedef struct CachedPlanSource
/* State kept to help decide whether to use custom or generic plans: */
double generic_cost; /* cost of generic plan, or -1 if not known */
double total_custom_cost; /* total cost of custom plans so far */
int num_custom_plans; /* number of plans included in total */
int64 num_custom_plans; /* # of custom plans included in total */
int64 num_generic_plans; /* # of generic plans */
} CachedPlanSource;
/*

43
src/test/regress/expected/plancache.out
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@ -284,7 +284,15 @@ insert into test_mode select 1 from generate_series(1,1000) union all select 2;
create index on test_mode (a);
analyze test_mode;
prepare test_mode_pp (int) as select count(*) from test_mode where a = $1;
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
name | generic_plans | custom_plans
--------------+---------------+--------------
test_mode_pp | 0 | 0
(1 row)
-- up to 5 executions, custom plan is used
set plan_cache_mode to auto;
explain (costs off) execute test_mode_pp(2);
QUERY PLAN
----------------------------------------------------------
@ -293,6 +301,13 @@ explain (costs off) execute test_mode_pp(2);
Index Cond: (a = 2)
(3 rows)
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
name | generic_plans | custom_plans
--------------+---------------+--------------
test_mode_pp | 0 | 1
(1 row)
-- force generic plan
set plan_cache_mode to force_generic_plan;
explain (costs off) execute test_mode_pp(2);
@ -303,6 +318,13 @@ explain (costs off) execute test_mode_pp(2);
Filter: (a = $1)
(3 rows)
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
name | generic_plans | custom_plans
--------------+---------------+--------------
test_mode_pp | 1 | 1
(1 row)
-- get to generic plan by 5 executions
set plan_cache_mode to auto;
execute test_mode_pp(1); -- 1x
@ -329,12 +351,26 @@ execute test_mode_pp(1); -- 4x
1000
(1 row)
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
name | generic_plans | custom_plans
--------------+---------------+--------------
test_mode_pp | 1 | 5
(1 row)
execute test_mode_pp(1); -- 5x
count
-------
1000
(1 row)
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
name | generic_plans | custom_plans
--------------+---------------+--------------
test_mode_pp | 2 | 5
(1 row)
-- we should now get a really bad plan
explain (costs off) execute test_mode_pp(2);
QUERY PLAN
@ -354,4 +390,11 @@ explain (costs off) execute test_mode_pp(2);
Index Cond: (a = 2)
(3 rows)
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
name | generic_plans | custom_plans
--------------+---------------+--------------
test_mode_pp | 3 | 6
(1 row)
drop table test_mode;

6
src/test/regress/expected/rules.out
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@ -1428,8 +1428,10 @@ pg_prepared_statements| SELECT p.name,
p.statement,
p.prepare_time,
p.parameter_types,
p.from_sql
FROM pg_prepared_statement() p(name, statement, prepare_time, parameter_types, from_sql);
p.from_sql,
p.generic_plans,
p.custom_plans
FROM pg_prepared_statement() p(name, statement, prepare_time, parameter_types, from_sql, generic_plans, custom_plans);
pg_prepared_xacts| SELECT p.transaction,
p.gid,
p.prepared,

13
src/test/regress/sql/plancache.sql
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@ -186,13 +186,20 @@ create index on test_mode (a);
analyze test_mode;
prepare test_mode_pp (int) as select count(*) from test_mode where a = $1;
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
-- up to 5 executions, custom plan is used
set plan_cache_mode to auto;
explain (costs off) execute test_mode_pp(2);
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
-- force generic plan
set plan_cache_mode to force_generic_plan;
explain (costs off) execute test_mode_pp(2);
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
-- get to generic plan by 5 executions
set plan_cache_mode to auto;
@ -200,7 +207,11 @@ execute test_mode_pp(1); -- 1x
execute test_mode_pp(1); -- 2x
execute test_mode_pp(1); -- 3x
execute test_mode_pp(1); -- 4x
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
execute test_mode_pp(1); -- 5x
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
-- we should now get a really bad plan
explain (costs off) execute test_mode_pp(2);
@ -208,5 +219,7 @@ explain (costs off) execute test_mode_pp(2);
-- but we can force a custom plan
set plan_cache_mode to force_custom_plan;
explain (costs off) execute test_mode_pp(2);
select name, generic_plans, custom_plans from pg_prepared_statements
where name = 'test_mode_pp';
drop table test_mode;

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