From: | Marcin Polak <marcin(at)indigo(dot)pl> |
---|---|
To: | pgsql-bugs(at)postgresql(dot)org |
Subject: | BUG REPORT |
Date: | 1999-03-19 19:09:13 |
Message-ID: | Pine.LNX.3.96.990319194851.1247A-200000@lokalik.on.the.Sun |
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Thread: | |
Lists: | pgsql-bugs |
============================================================================
POSTGRESQL BUG REPORT TEMPLATE
============================================================================
Your name :Marcin Polak
Your email address :marcin(at)indigo(dot)pl
System Configuration
---------------------
Architecture (example: Intel Pentium) :Intel Pentium
Operating System (example: Linux 2.0.26 ELF) :Linux 2.0.35 ELF
PostgreSQL version (example: PostgreSQL-6.4) :PostgreSQL-6.4.2
Compiler used (example: gcc 2.8.0) :egcs-1.1b-2
Please enter a FULL description of your problem:
------------------------------------------------
After creating index on a text field (1000000 records), Postgres doesn't
give proper answer on a query using this index.
Please describe a way to repeat the problem. Please try to provide a
concise reproducible example, if at all possible:
----------------------------------------------------------------------
I've created database with a python sript (attached)
It makes:
"create table tt2_1 (ntt int, nttext int, ntttext varchar(50) )"
and then insert 1000000 records.
Then I've created index:
create index i1 on tt2_1(ntttext); -- index on third column
When I'm connected with psql, I'm doing:
select * from tt2_1 where nttext = 123456 and ntttext =
'123456123456123456';
and answer is:
ntt|nttext| ntttext
------+------+------------------
123456|123456|123456123456123456
(1 row)
and that's right;
But on:
marcin=> select * from tt2_1 where ntttext = '123456123456123456';
ntt|nttext|ntttext
---+------+-------
(0 rows)
and that's not right, am I right :-) ?
It happens when I'm using similar like condition, like
"blah blah ntttext like '123456%' "
What more:
postgres is run with parameters: -B 1000 -o -F
If you know how this problem might be fixed, list the solution below:
---------------------------------------------------------------------
Sorry :-(.
BTW. How big database you think, Postgres can manage with?
PS. My interesting observation is, that if I create six or seven tables (I
don't remember exactly how many) with 1000 to 5000 records and do simple
"SELECT" using all tables Postgres answers in a second (with indices), and
with one more table, when GEQO turns on, I'm getting answer in 30 seconds.
I can't see, in which condition it helps?
Regards from Poland
Marcin
Attachment | Content-Type | Size |
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gendb2.py | text/plain | 375 bytes |
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