Ok, I've done the test case (see attachment).
8.3.3 has passed it.
8.3.4 hasn't passed in ~99% times I run it.
Steps to reproduce:
1. install pg 8.3.4, do initdb, start pg
2. correct PSQL parameter in pg-8.3.4_index_update_test.sh
3. run pg-8.3.4_index_update_test.sh few times
And you will see something like this:
...
------------------------------------------
2nd time obtaining "seq-scan" count and plan...
------------------------------------------
SELECT table1_flag, count(*) FROM table1
GROUP BY table1_flag;
table1_flag | count
-------------+-------
1 | 100
(1 row)
EXPLAIN ANALYZE SELECT table1_flag, count(*) FROM table1
GROUP BY table1_flag;
QUERY PLAN
-----------------------------------------------------------------------------------------------------------
HashAggregate (cost=15.00..15.01 rows=1 width=2) (actual
time=0.140..0.140 rows=1 loops=1)
-> Seq Scan on table1 (cost=0.00..12.00 rows=600 width=2) (actual
time=0.004..0.059 rows=100 loops=1)
Total runtime: 0.172 ms
(3 rows)
------------------------------------------
2nd time obtaining "index-scan" count and plan...
------------------------------------------
SELECT count(*) FROM table1
WHERE table1_flag = 1;
count
-------
98
(1 row)
EXPLAIN ANALYZE SELECT count(*) FROM table1
WHERE table1_flag = 1;
QUERY
PLAN
--------------------------------------------------------------------------------------------------------------------------------------
Aggregate (cost=8.27..8.28 rows=1 width=0) (actual time=0.451..0.451
rows=1 loops=1)
-> Index Scan using i_table1__table1_point on table1
(cost=0.00..8.27 rows=1 width=0) (actual time=0.011..0.408 rows=98
loops=1)
Total runtime: 0.477 ms
(3 rows)
--
Regards,
Sergey Konoplev
--
PostgreSQL articles in english & russian
http://gray-hemp.blogspot.com/search/label/postgresql/
Attachment:
pg-8.3.4_index_update_test.tar.gz
Description: GNU Zip compressed data
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