Attached patch fixes an oversight that tablesample cannot be used with
partitioned tables:
create table p (a int) partition by list (a);
select * from p tablesample bernoulli (50);
ERROR: TABLESAMPLE clause can only be applied to tables and materialized
views
Thanks,
Amit
>From d9c412ea14b005b4c6013026c6c62eab97727c3c Mon Sep 17 00:00:00 2001
From: amit <amitlangot...@gmail.com>
Date: Wed, 22 Feb 2017 16:27:35 +0900
Subject: [PATCH] Partitioned tables support tablesample
---
src/backend/parser/parse_clause.c | 3 ++-
src/test/regress/expected/tablesample.out | 18 ++++++++++++++++++
src/test/regress/sql/tablesample.sql | 8 ++++++++
3 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index fecc1d6598..b5eae56006 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -907,7 +907,8 @@ transformFromClauseItem(ParseState *pstate, Node *n,
rte = rt_fetch(rtr->rtindex, pstate->p_rtable);
/* We only support this on plain relations and matviews */
if (rte->relkind != RELKIND_RELATION &&
- rte->relkind != RELKIND_MATVIEW)
+ rte->relkind != RELKIND_MATVIEW &&
+ rte->relkind != RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("TABLESAMPLE clause can only be applied to tables and materialized views"),
diff --git a/src/test/regress/expected/tablesample.out b/src/test/regress/expected/tablesample.out
index 7e91b958ae..b18e420e9b 100644
--- a/src/test/regress/expected/tablesample.out
+++ b/src/test/regress/expected/tablesample.out
@@ -313,3 +313,21 @@ SELECT q.* FROM (SELECT * FROM test_tablesample) as q TABLESAMPLE BERNOULLI (5);
ERROR: syntax error at or near "TABLESAMPLE"
LINE 1: ...CT q.* FROM (SELECT * FROM test_tablesample) as q TABLESAMPL...
^
+-- check partitioned tables support tablesample
+create table parted_sample (a int) partition by list (a);
+create table parted_sample_1 partition of parted_sample for values in (1);
+create table parted_sample_2 partition of parted_sample for values in (2);
+explain (costs off)
+ select * from parted_sample tablesample bernoulli (100);
+ QUERY PLAN
+-------------------------------------------
+ Append
+ -> Sample Scan on parted_sample
+ Sampling: bernoulli ('100'::real)
+ -> Sample Scan on parted_sample_1
+ Sampling: bernoulli ('100'::real)
+ -> Sample Scan on parted_sample_2
+ Sampling: bernoulli ('100'::real)
+(7 rows)
+
+drop table parted_sample, parted_sample_1, parted_sample_2;
diff --git a/src/test/regress/sql/tablesample.sql b/src/test/regress/sql/tablesample.sql
index eec9793496..c39fe4b750 100644
--- a/src/test/regress/sql/tablesample.sql
+++ b/src/test/regress/sql/tablesample.sql
@@ -100,3 +100,11 @@ WITH query_select AS (SELECT * FROM test_tablesample)
SELECT * FROM query_select TABLESAMPLE BERNOULLI (5.5) REPEATABLE (1);
SELECT q.* FROM (SELECT * FROM test_tablesample) as q TABLESAMPLE BERNOULLI (5);
+
+-- check partitioned tables support tablesample
+create table parted_sample (a int) partition by list (a);
+create table parted_sample_1 partition of parted_sample for values in (1);
+create table parted_sample_2 partition of parted_sample for values in (2);
+explain (costs off)
+ select * from parted_sample tablesample bernoulli (100);
+drop table parted_sample, parted_sample_1, parted_sample_2;
--
2.11.0
--
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