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postgresql/src/test/regress/sql/brin.sql
Tomas Vondra 7577dd8480 Properly detoast data in brin_form_tuple 
brin_form_tuple failed to consider the values may be toasted, inserting
the toast pointer into the index. This may easily result in index
corruption, as the toast data may be deleted and cleaned up by vacuum.
The cleanup however does not care about indexes, leaving invalid toast
pointers behind, which triggers errors like this:

  ERROR:  missing chunk number 0 for toast value 16433 in pg_toast_16426

A less severe consequence are inconsistent failures due to the index row
being too large, depending on whether brin_form_tuple operated on plain
or toasted version of the row. For example

    CREATE TABLE t (val TEXT);
    INSERT INTO t VALUES ('... long value ...')
    CREATE INDEX idx ON t USING brin (val);

would likely succeed, as the row would likely include toast pointer.
Switching the order of INSERT and CREATE INDEX would likely fail:

    ERROR:  index row size 8712 exceeds maximum 8152 for index "idx"

because this happens before the row values are toasted.

The bug exists since PostgreSQL 9.5 where BRIN indexes were introduced.
So backpatch all the way back.

Author: Tomas Vondra
Reviewed-by: Alvaro Herrera
Backpatch-through: 9.5
Discussion: https://postgr.es/m/20201001184133.oq5uq75sb45pu3aw@development
Discussion: https://postgr.es/m/20201104010544.zexj52mlldagzowv%40development
2020-11-07 00:39:19 +01:00

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CREATE TABLE brintest (byteacol bytea,
charcol "char",
namecol name,
int8col bigint,
int2col smallint,
int4col integer,
textcol text,
oidcol oid,
tidcol tid,
float4col real,
float8col double precision,
macaddrcol macaddr,
inetcol inet,
cidrcol cidr,
bpcharcol character,
datecol date,
timecol time without time zone,
timestampcol timestamp without time zone,
timestamptzcol timestamp with time zone,
intervalcol interval,
timetzcol time with time zone,
bitcol bit(10),
varbitcol bit varying(16),
numericcol numeric,
uuidcol uuid,
int4rangecol int4range,
lsncol pg_lsn,
boxcol box
) WITH (fillfactor=10, autovacuum_enabled=off);
INSERT INTO brintest SELECT
repeat(stringu1, 8)::bytea,
substr(stringu1, 1, 1)::"char",
stringu1::name, 142857 * tenthous,
thousand,
twothousand,
repeat(stringu1, 8),
unique1::oid,
format('(%s,%s)', tenthous, twenty)::tid,
(four + 1.0)/(hundred+1),
odd::float8 / (tenthous + 1),
format('%s:00:%s:00:%s:00', to_hex(odd), to_hex(even), to_hex(hundred))::macaddr,
inet '10.2.3.4/24' + tenthous,
cidr '10.2.3/24' + tenthous,
substr(stringu1, 1, 1)::bpchar,
date '1995-08-15' + tenthous,
time '01:20:30' + thousand * interval '18.5 second',
timestamp '1942-07-23 03:05:09' + tenthous * interval '36.38 hours',
timestamptz '1972-10-10 03:00' + thousand * interval '1 hour',
justify_days(justify_hours(tenthous * interval '12 minutes')),
timetz '01:30:20+02' + hundred * interval '15 seconds',
thousand::bit(10),
tenthous::bit(16)::varbit,
tenthous::numeric(36,30) * fivethous * even / (hundred + 1),
format('%s%s-%s-%s-%s-%s%s%s', to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'))::uuid,
int4range(thousand, twothousand),
format('%s/%s%s', odd, even, tenthous)::pg_lsn,
box(point(odd, even), point(thousand, twothousand))
FROM tenk1 ORDER BY unique2 LIMIT 100;
-- throw in some NULL's and different values
INSERT INTO brintest (inetcol, cidrcol, int4rangecol) SELECT
inet 'fe80::6e40:8ff:fea9:8c46' + tenthous,
cidr 'fe80::6e40:8ff:fea9:8c46' + tenthous,
'empty'::int4range
FROM tenk1 ORDER BY thousand, tenthous LIMIT 25;
CREATE INDEX brinidx ON brintest USING brin (
byteacol,
charcol,
namecol,
int8col,
int2col,
int4col,
textcol,
oidcol,
tidcol,
float4col,
float8col,
macaddrcol,
inetcol inet_inclusion_ops,
inetcol inet_minmax_ops,
cidrcol inet_inclusion_ops,
cidrcol inet_minmax_ops,
bpcharcol,
datecol,
timecol,
timestampcol,
timestamptzcol,
intervalcol,
timetzcol,
bitcol,
varbitcol,
numericcol,
uuidcol,
int4rangecol,
lsncol,
boxcol
) with (pages_per_range = 1);
CREATE TABLE brinopers (colname name, typ text,
op text[], value text[], matches int[],
check (cardinality(op) = cardinality(value)),
check (cardinality(op) = cardinality(matches)));
INSERT INTO brinopers VALUES
('byteacol', 'bytea',
'{>, >=, =, <=, <}',
'{AAAAAA, AAAAAA, BNAAAABNAAAABNAAAABNAAAABNAAAABNAAAABNAAAABNAAAA, ZZZZZZ, ZZZZZZ}',
'{100, 100, 1, 100, 100}'),
('charcol', '"char"',
'{>, >=, =, <=, <}',
'{A, A, M, Z, Z}',
'{97, 100, 6, 100, 98}'),
('namecol', 'name',
'{>, >=, =, <=, <}',
'{AAAAAA, AAAAAA, MAAAAA, ZZAAAA, ZZAAAA}',
'{100, 100, 2, 100, 100}'),
('int2col', 'int2',
'{>, >=, =, <=, <}',
'{0, 0, 800, 999, 999}',
'{100, 100, 1, 100, 100}'),
('int2col', 'int4',
'{>, >=, =, <=, <}',
'{0, 0, 800, 999, 1999}',
'{100, 100, 1, 100, 100}'),
('int2col', 'int8',
'{>, >=, =, <=, <}',
'{0, 0, 800, 999, 1428427143}',
'{100, 100, 1, 100, 100}'),
('int4col', 'int2',
'{>, >=, =, <=, <}',
'{0, 0, 800, 1999, 1999}',
'{100, 100, 1, 100, 100}'),
('int4col', 'int4',
'{>, >=, =, <=, <}',
'{0, 0, 800, 1999, 1999}',
'{100, 100, 1, 100, 100}'),
('int4col', 'int8',
'{>, >=, =, <=, <}',
'{0, 0, 800, 1999, 1428427143}',
'{100, 100, 1, 100, 100}'),
('int8col', 'int2',
'{>, >=}',
'{0, 0}',
'{100, 100}'),
('int8col', 'int4',
'{>, >=}',
'{0, 0}',
'{100, 100}'),
('int8col', 'int8',
'{>, >=, =, <=, <}',
'{0, 0, 1257141600, 1428427143, 1428427143}',
'{100, 100, 1, 100, 100}'),
('textcol', 'text',
'{>, >=, =, <=, <}',
'{ABABAB, ABABAB, BNAAAABNAAAABNAAAABNAAAABNAAAABNAAAABNAAAABNAAAA, ZZAAAA, ZZAAAA}',
'{100, 100, 1, 100, 100}'),
('oidcol', 'oid',
'{>, >=, =, <=, <}',
'{0, 0, 8800, 9999, 9999}',
'{100, 100, 1, 100, 100}'),
('tidcol', 'tid',
'{>, >=, =, <=, <}',
'{"(0,0)", "(0,0)", "(8800,0)", "(9999,19)", "(9999,19)"}',
'{100, 100, 1, 100, 100}'),
('float4col', 'float4',
'{>, >=, =, <=, <}',
'{0.0103093, 0.0103093, 1, 1, 1}',
'{100, 100, 4, 100, 96}'),
('float4col', 'float8',
'{>, >=, =, <=, <}',
'{0.0103093, 0.0103093, 1, 1, 1}',
'{100, 100, 4, 100, 96}'),
('float8col', 'float4',
'{>, >=, =, <=, <}',
'{0, 0, 0, 1.98, 1.98}',
'{99, 100, 1, 100, 100}'),
('float8col', 'float8',
'{>, >=, =, <=, <}',
'{0, 0, 0, 1.98, 1.98}',
'{99, 100, 1, 100, 100}'),
('macaddrcol', 'macaddr',
'{>, >=, =, <=, <}',
'{00:00:01:00:00:00, 00:00:01:00:00:00, 2c:00:2d:00:16:00, ff:fe:00:00:00:00, ff:fe:00:00:00:00}',
'{99, 100, 2, 100, 100}'),
('inetcol', 'inet',
'{&&, =, <, <=, >, >=, >>=, >>, <<=, <<}',
'{10/8, 10.2.14.231/24, 255.255.255.255, 255.255.255.255, 0.0.0.0, 0.0.0.0, 10.2.14.231/24, 10.2.14.231/25, 10.2.14.231/8, 0/0}',
'{100, 1, 100, 100, 125, 125, 2, 2, 100, 100}'),
('inetcol', 'inet',
'{&&, >>=, <<=, =}',
'{fe80::6e40:8ff:fea9:a673/32, fe80::6e40:8ff:fea9:8c46, fe80::6e40:8ff:fea9:a673/32, fe80::6e40:8ff:fea9:8c46}',
'{25, 1, 25, 1}'),
('inetcol', 'cidr',
'{&&, <, <=, >, >=, >>=, >>, <<=, <<}',
'{10/8, 255.255.255.255, 255.255.255.255, 0.0.0.0, 0.0.0.0, 10.2.14/24, 10.2.14/25, 10/8, 0/0}',
'{100, 100, 100, 125, 125, 2, 2, 100, 100}'),
('inetcol', 'cidr',
'{&&, >>=, <<=, =}',
'{fe80::/32, fe80::6e40:8ff:fea9:8c46, fe80::/32, fe80::6e40:8ff:fea9:8c46}',
'{25, 1, 25, 1}'),
('cidrcol', 'inet',
'{&&, =, <, <=, >, >=, >>=, >>, <<=, <<}',
'{10/8, 10.2.14/24, 255.255.255.255, 255.255.255.255, 0.0.0.0, 0.0.0.0, 10.2.14.231/24, 10.2.14.231/25, 10.2.14.231/8, 0/0}',
'{100, 2, 100, 100, 125, 125, 2, 2, 100, 100}'),
('cidrcol', 'inet',
'{&&, >>=, <<=, =}',
'{fe80::6e40:8ff:fea9:a673/32, fe80::6e40:8ff:fea9:8c46, fe80::6e40:8ff:fea9:a673/32, fe80::6e40:8ff:fea9:8c46}',
'{25, 1, 25, 1}'),
('cidrcol', 'cidr',
'{&&, =, <, <=, >, >=, >>=, >>, <<=, <<}',
'{10/8, 10.2.14/24, 255.255.255.255, 255.255.255.255, 0.0.0.0, 0.0.0.0, 10.2.14/24, 10.2.14/25, 10/8, 0/0}',
'{100, 2, 100, 100, 125, 125, 2, 2, 100, 100}'),
('cidrcol', 'cidr',
'{&&, >>=, <<=, =}',
'{fe80::/32, fe80::6e40:8ff:fea9:8c46, fe80::/32, fe80::6e40:8ff:fea9:8c46}',
'{25, 1, 25, 1}'),
('bpcharcol', 'bpchar',
'{>, >=, =, <=, <}',
'{A, A, W, Z, Z}',
'{97, 100, 6, 100, 98}'),
('datecol', 'date',
'{>, >=, =, <=, <}',
'{1995-08-15, 1995-08-15, 2009-12-01, 2022-12-30, 2022-12-30}',
'{100, 100, 1, 100, 100}'),
('timecol', 'time',
'{>, >=, =, <=, <}',
'{01:20:30, 01:20:30, 02:28:57, 06:28:31.5, 06:28:31.5}',
'{100, 100, 1, 100, 100}'),
('timestampcol', 'timestamp',
'{>, >=, =, <=, <}',
'{1942-07-23 03:05:09, 1942-07-23 03:05:09, 1964-03-24 19:26:45, 1984-01-20 22:42:21, 1984-01-20 22:42:21}',
'{100, 100, 1, 100, 100}'),
('timestampcol', 'timestamptz',
'{>, >=, =, <=, <}',
'{1942-07-23 03:05:09, 1942-07-23 03:05:09, 1964-03-24 19:26:45, 1984-01-20 22:42:21, 1984-01-20 22:42:21}',
'{100, 100, 1, 100, 100}'),
('timestamptzcol', 'timestamptz',
'{>, >=, =, <=, <}',
'{1972-10-10 03:00:00-04, 1972-10-10 03:00:00-04, 1972-10-19 09:00:00-07, 1972-11-20 19:00:00-03, 1972-11-20 19:00:00-03}',
'{100, 100, 1, 100, 100}'),
('intervalcol', 'interval',
'{>, >=, =, <=, <}',
'{00:00:00, 00:00:00, 1 mons 13 days 12:24, 2 mons 23 days 07:48:00, 1 year}',
'{100, 100, 1, 100, 100}'),
('timetzcol', 'timetz',
'{>, >=, =, <=, <}',
'{01:30:20+02, 01:30:20+02, 01:35:50+02, 23:55:05+02, 23:55:05+02}',
'{99, 100, 2, 100, 100}'),
('bitcol', 'bit(10)',
'{>, >=, =, <=, <}',
'{0000000010, 0000000010, 0011011110, 1111111000, 1111111000}',
'{100, 100, 1, 100, 100}'),
('varbitcol', 'varbit(16)',
'{>, >=, =, <=, <}',
'{0000000000000100, 0000000000000100, 0001010001100110, 1111111111111000, 1111111111111000}',
'{100, 100, 1, 100, 100}'),
('numericcol', 'numeric',
'{>, >=, =, <=, <}',
'{0.00, 0.01, 2268164.347826086956521739130434782609, 99470151.9, 99470151.9}',
'{100, 100, 1, 100, 100}'),
('uuidcol', 'uuid',
'{>, >=, =, <=, <}',
'{00040004-0004-0004-0004-000400040004, 00040004-0004-0004-0004-000400040004, 52225222-5222-5222-5222-522252225222, 99989998-9998-9998-9998-999899989998, 99989998-9998-9998-9998-999899989998}',
'{100, 100, 1, 100, 100}'),
('int4rangecol', 'int4range',
'{<<, &<, &&, &>, >>, @>, <@, =, <, <=, >, >=}',
'{"[10000,)","[10000,)","(,]","[3,4)","[36,44)","(1500,1501]","[3,4)","[222,1222)","[36,44)","[43,1043)","[367,4466)","[519,)"}',
'{53, 53, 53, 53, 50, 22, 72, 1, 74, 75, 34, 21}'),
('int4rangecol', 'int4range',
'{@>, <@, =, <=, >, >=}',
'{empty, empty, empty, empty, empty, empty}',
'{125, 72, 72, 72, 53, 125}'),
('int4rangecol', 'int4',
'{@>}',
'{1500}',
'{22}'),
('lsncol', 'pg_lsn',
'{>, >=, =, <=, <, IS, IS NOT}',
'{0/1200, 0/1200, 44/455222, 198/1999799, 198/1999799, NULL, NULL}',
'{100, 100, 1, 100, 100, 25, 100}'),
('boxcol', 'point',
'{@>}',
'{"(500,43)"}',
'{11}'),
('boxcol', 'box',
'{<<, &<, &&, &>, >>, <<|, &<|, |&>, |>>, @>, <@, ~=}',
'{"((1000,2000),(3000,4000))","((1,2),(3000,4000))","((1,2),(3000,4000))","((1,2),(3000,4000))","((1,2),(3,4))","((1000,2000),(3000,4000))","((1,2000),(3,4000))","((1000,2),(3000,4))","((1,2),(3,4))","((1,2),(300,400))","((1,2),(3000,4000))","((222,1222),(44,45))"}',
'{100, 100, 100, 99, 96, 100, 100, 99, 96, 1, 99, 1}');
DO $x$
DECLARE
r record;
r2 record;
cond text;
idx_ctids tid[];
ss_ctids tid[];
count int;
plan_ok bool;
plan_line text;
BEGIN
FOR r IN SELECT colname, oper, typ, value[ordinality], matches[ordinality] FROM brinopers, unnest(op) WITH ORDINALITY AS oper LOOP
-- prepare the condition
IF r.value IS NULL THEN
cond := format('%I %s %L', r.colname, r.oper, r.value);
ELSE
cond := format('%I %s %L::%s', r.colname, r.oper, r.value, r.typ);
END IF;
-- run the query using the brin index
SET enable_seqscan = 0;
SET enable_bitmapscan = 1;
plan_ok := false;
FOR plan_line IN EXECUTE format($y$EXPLAIN SELECT array_agg(ctid) FROM brintest WHERE %s $y$, cond) LOOP
IF plan_line LIKE '%Bitmap Heap Scan on brintest%' THEN
plan_ok := true;
END IF;
END LOOP;
IF NOT plan_ok THEN
RAISE WARNING 'did not get bitmap indexscan plan for %', r;
END IF;
EXECUTE format($y$SELECT array_agg(ctid) FROM brintest WHERE %s $y$, cond)
INTO idx_ctids;
-- run the query using a seqscan
SET enable_seqscan = 1;
SET enable_bitmapscan = 0;
plan_ok := false;
FOR plan_line IN EXECUTE format($y$EXPLAIN SELECT array_agg(ctid) FROM brintest WHERE %s $y$, cond) LOOP
IF plan_line LIKE '%Seq Scan on brintest%' THEN
plan_ok := true;
END IF;
END LOOP;
IF NOT plan_ok THEN
RAISE WARNING 'did not get seqscan plan for %', r;
END IF;
EXECUTE format($y$SELECT array_agg(ctid) FROM brintest WHERE %s $y$, cond)
INTO ss_ctids;
-- make sure both return the same results
count := array_length(idx_ctids, 1);
IF NOT (count = array_length(ss_ctids, 1) AND
idx_ctids @> ss_ctids AND
idx_ctids <@ ss_ctids) THEN
-- report the results of each scan to make the differences obvious
RAISE WARNING 'something not right in %: count %', r, count;
SET enable_seqscan = 1;
SET enable_bitmapscan = 0;
FOR r2 IN EXECUTE 'SELECT ' || r.colname || ' FROM brintest WHERE ' || cond LOOP
RAISE NOTICE 'seqscan: %', r2;
END LOOP;
SET enable_seqscan = 0;
SET enable_bitmapscan = 1;
FOR r2 IN EXECUTE 'SELECT ' || r.colname || ' FROM brintest WHERE ' || cond LOOP
RAISE NOTICE 'bitmapscan: %', r2;
END LOOP;
END IF;
-- make sure we found expected number of matches
IF count != r.matches THEN RAISE WARNING 'unexpected number of results % for %', count, r; END IF;
END LOOP;
END;
$x$;
RESET enable_seqscan;
RESET enable_bitmapscan;
INSERT INTO brintest SELECT
repeat(stringu1, 42)::bytea,
substr(stringu1, 1, 1)::"char",
stringu1::name, 142857 * tenthous,
thousand,
twothousand,
repeat(stringu1, 42),
unique1::oid,
format('(%s,%s)', tenthous, twenty)::tid,
(four + 1.0)/(hundred+1),
odd::float8 / (tenthous + 1),
format('%s:00:%s:00:%s:00', to_hex(odd), to_hex(even), to_hex(hundred))::macaddr,
inet '10.2.3.4' + tenthous,
cidr '10.2.3/24' + tenthous,
substr(stringu1, 1, 1)::bpchar,
date '1995-08-15' + tenthous,
time '01:20:30' + thousand * interval '18.5 second',
timestamp '1942-07-23 03:05:09' + tenthous * interval '36.38 hours',
timestamptz '1972-10-10 03:00' + thousand * interval '1 hour',
justify_days(justify_hours(tenthous * interval '12 minutes')),
timetz '01:30:20' + hundred * interval '15 seconds',
thousand::bit(10),
tenthous::bit(16)::varbit,
tenthous::numeric(36,30) * fivethous * even / (hundred + 1),
format('%s%s-%s-%s-%s-%s%s%s', to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'), to_char(tenthous, 'FM0000'))::uuid,
int4range(thousand, twothousand),
format('%s/%s%s', odd, even, tenthous)::pg_lsn,
box(point(odd, even), point(thousand, twothousand))
FROM tenk1 ORDER BY unique2 LIMIT 5 OFFSET 5;
SELECT brin_desummarize_range('brinidx', 0);
VACUUM brintest; -- force a summarization cycle in brinidx
UPDATE brintest SET int8col = int8col * int4col;
UPDATE brintest SET textcol = '' WHERE textcol IS NOT NULL;
-- Tests for brin_summarize_new_values
SELECT brin_summarize_new_values('brintest'); -- error, not an index
SELECT brin_summarize_new_values('tenk1_unique1'); -- error, not a BRIN index
SELECT brin_summarize_new_values('brinidx'); -- ok, no change expected
-- Tests for brin_desummarize_range
SELECT brin_desummarize_range('brinidx', -1); -- error, invalid range
SELECT brin_desummarize_range('brinidx', 0);
SELECT brin_desummarize_range('brinidx', 0);
SELECT brin_desummarize_range('brinidx', 100000000);
-- Test brin_summarize_range
CREATE TABLE brin_summarize (
value int
) WITH (fillfactor=10, autovacuum_enabled=false);
CREATE INDEX brin_summarize_idx ON brin_summarize USING brin (value) WITH (pages_per_range=2);
-- Fill a few pages
DO $$
DECLARE curtid tid;
BEGIN
LOOP
INSERT INTO brin_summarize VALUES (1) RETURNING ctid INTO curtid;
EXIT WHEN curtid > tid '(2, 0)';
END LOOP;
END;
$$;
-- summarize one range
SELECT brin_summarize_range('brin_summarize_idx', 0);
-- nothing: already summarized
SELECT brin_summarize_range('brin_summarize_idx', 1);
-- summarize one range
SELECT brin_summarize_range('brin_summarize_idx', 2);
-- nothing: page doesn't exist in table
SELECT brin_summarize_range('brin_summarize_idx', 4294967295);
-- invalid block number values
SELECT brin_summarize_range('brin_summarize_idx', -1);
SELECT brin_summarize_range('brin_summarize_idx', 4294967296);
-- test value merging in add_value
CREATE TABLE brintest_2 (n numrange);
CREATE INDEX brinidx_2 ON brintest_2 USING brin (n);
INSERT INTO brintest_2 VALUES ('empty');
INSERT INTO brintest_2 VALUES (numrange(0, 2^1000::numeric));
INSERT INTO brintest_2 VALUES ('(-1, 0)');
SELECT brin_desummarize_range('brinidx', 0);
SELECT brin_summarize_range('brinidx', 0);
DROP TABLE brintest_2;
-- test brin cost estimates behave sanely based on correlation of values
CREATE TABLE brin_test (a INT, b INT);
INSERT INTO brin_test SELECT x/100,x%100 FROM generate_series(1,10000) x(x);
CREATE INDEX brin_test_a_idx ON brin_test USING brin (a) WITH (pages_per_range = 2);
CREATE INDEX brin_test_b_idx ON brin_test USING brin (b) WITH (pages_per_range = 2);
VACUUM ANALYZE brin_test;
-- Ensure brin index is used when columns are perfectly correlated
EXPLAIN (COSTS OFF) SELECT * FROM brin_test WHERE a = 1;
-- Ensure brin index is not used when values are not correlated
EXPLAIN (COSTS OFF) SELECT * FROM brin_test WHERE b = 1;
-- make sure data are properly de-toasted in BRIN index
CREATE TABLE brintest_3 (a text, b text, c text, d text);
-- long random strings (~2000 chars each, so ~6kB for min/max on two
-- columns) to trigger toasting
WITH rand_value AS (SELECT string_agg(md5(i::text),'') AS val FROM generate_series(1,60) s(i))
INSERT INTO brintest_3
SELECT val, val, val, val FROM rand_value;
CREATE INDEX brin_test_toast_idx ON brintest_3 USING brin (b, c);
DELETE FROM brintest_3;
-- We need to wait a bit for all transactions to complete, so that the
-- vacuum actually removes the TOAST rows. Creating an index concurrently
-- is a one way to achieve that, because it does exactly such wait.
CREATE INDEX CONCURRENTLY brin_test_temp_idx ON brintest_3(a);
DROP INDEX brin_test_temp_idx;
-- vacuum the table, to discard TOAST data
VACUUM brintest_3;
-- retry insert with a different random-looking (but deterministic) value
-- the value is different, and so should replace either min or max in the
-- brin summary
WITH rand_value AS (SELECT string_agg(md5((-i)::text),'') AS val FROM generate_series(1,60) s(i))
INSERT INTO brintest_3
SELECT val, val, val, val FROM rand_value;
-- now try some queries, accessing the brin index
SET enable_seqscan = off;
EXPLAIN (COSTS OFF)
SELECT * FROM brintest_3 WHERE b < '0';
SELECT * FROM brintest_3 WHERE b < '0';
DROP TABLE brintest_3;
RESET enable_seqscan;
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