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Diffstat (limited to 'src/test/regress/sql/tablesample.sql')
-rw-r--r-- | src/test/regress/sql/tablesample.sql | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/src/test/regress/sql/tablesample.sql b/src/test/regress/sql/tablesample.sql new file mode 100644 index 0000000..aa17994 --- /dev/null +++ b/src/test/regress/sql/tablesample.sql @@ -0,0 +1,110 @@ +CREATE TABLE test_tablesample (id int, name text) WITH (fillfactor=10); +-- use fillfactor so we don't have to load too much data to get multiple pages + +INSERT INTO test_tablesample + SELECT i, repeat(i::text, 200) FROM generate_series(0, 9) s(i); + +SELECT t.id FROM test_tablesample AS t TABLESAMPLE SYSTEM (50) REPEATABLE (0); +SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (100.0/11) REPEATABLE (0); +SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (50) REPEATABLE (0); +SELECT id FROM test_tablesample TABLESAMPLE BERNOULLI (50) REPEATABLE (0); +SELECT id FROM test_tablesample TABLESAMPLE BERNOULLI (5.5) REPEATABLE (0); + +-- 100% should give repeatable count results (ie, all rows) in any case +SELECT count(*) FROM test_tablesample TABLESAMPLE SYSTEM (100); +SELECT count(*) FROM test_tablesample TABLESAMPLE SYSTEM (100) REPEATABLE (1+2); +SELECT count(*) FROM test_tablesample TABLESAMPLE SYSTEM (100) REPEATABLE (0.4); + +CREATE VIEW test_tablesample_v1 AS + SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (10*2) REPEATABLE (2); +CREATE VIEW test_tablesample_v2 AS + SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (99); +\d+ test_tablesample_v1 +\d+ test_tablesample_v2 + +-- check a sampled query doesn't affect cursor in progress +BEGIN; +DECLARE tablesample_cur SCROLL CURSOR FOR + SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (50) REPEATABLE (0); + +FETCH FIRST FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; + +SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (50) REPEATABLE (0); + +FETCH NEXT FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; + +FETCH FIRST FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; +FETCH NEXT FROM tablesample_cur; + +CLOSE tablesample_cur; +END; + +EXPLAIN (COSTS OFF) + SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (50) REPEATABLE (2); +EXPLAIN (COSTS OFF) + SELECT * FROM test_tablesample_v1; + +-- check inheritance behavior +explain (costs off) + select count(*) from person tablesample bernoulli (100); +select count(*) from person tablesample bernoulli (100); +select count(*) from person; + +-- check that collations get assigned within the tablesample arguments +SELECT count(*) FROM test_tablesample TABLESAMPLE bernoulli (('1'::text < '0'::text)::int); + +-- check behavior during rescans, as well as correct handling of min/max pct +select * from + (values (0),(100)) v(pct), + lateral (select count(*) from tenk1 tablesample bernoulli (pct)) ss; +select * from + (values (0),(100)) v(pct), + lateral (select count(*) from tenk1 tablesample system (pct)) ss; +explain (costs off) +select pct, count(unique1) from + (values (0),(100)) v(pct), + lateral (select * from tenk1 tablesample bernoulli (pct)) ss + group by pct; +select pct, count(unique1) from + (values (0),(100)) v(pct), + lateral (select * from tenk1 tablesample bernoulli (pct)) ss + group by pct; +select pct, count(unique1) from + (values (0),(100)) v(pct), + lateral (select * from tenk1 tablesample system (pct)) ss + group by pct; + +-- errors +SELECT id FROM test_tablesample TABLESAMPLE FOOBAR (1); + +SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (NULL); +SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (50) REPEATABLE (NULL); + +SELECT id FROM test_tablesample TABLESAMPLE BERNOULLI (-1); +SELECT id FROM test_tablesample TABLESAMPLE BERNOULLI (200); +SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (-1); +SELECT id FROM test_tablesample TABLESAMPLE SYSTEM (200); + +SELECT id FROM test_tablesample_v1 TABLESAMPLE BERNOULLI (1); +INSERT INTO test_tablesample_v1 VALUES(1); + +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; |