mn index on
last_name and gender. Of course that assumes that you
have both columns in your WHERE clause combined with an
AND.
CREATE INDEX name_gender ON person (last_name, gender);
SELECT *
FROM person
WHERE last_name='Smith'
AND gender='male';
Regards,
Nikolaus
On Fr
needs to read all records.
For example
WHERE nombre LIKE '%lopez%';
However, this may get you a match for "Jennifer Lopez".
Many applications have a column first_name and another
for last_name.
Then you can have a more selective WHERE clause
WHERE last_name='Lopez'
AN
the tblPermissions table you updated its
statistics and therefore the second EXPLAIN looks
different.
Regards,
Nikolaus Dilger
"shreedhar" wrote:
>
> pmdummy=# explain SELECT projectid FROM tblPermissions
> pmdummy-# INNER JOIN tempaccountid ON
> tempaccountid.accid = tbl
minutes
to fast, I would keep the database down for at least 15
minutes after chaning the clock back to avoid mismatch
in the timestamps.
Regards,
Nikolaus Dilger
On Fri, 21 Feb 2003, "Donald Fraser" wrote:
Could somebody tell me the consequences
of setting the date forward in t
and if it is worth
the trouble. Numbers usually quoted are 10-20%. And
here things may be changing as operating systems and
chaching algorithems get better to mask the file system
overhead. As I mentioned the question is mute for
PostgeSQL because raw is currently not supported.
Regards,
Nikolaus
RAID
Option b) can be improved by using striping. Save your
money on the SCSI Ultra320 since the disk cant
transfer enough data anyway and buy more memory instead.
And finally good application design has a greater
impact on performance than a little faster hardware.
Regards,
Nikolaus Dilger
build the index.
Regards,
Nikolaus Dilger
On Wed, 02 October 2002, Raymond Chui wrote:
>
>
> I have some tables with huge data.
> The tables have column timestamp and float.
> I am try to keep up to 6 day of data values.
> What I do is execute SQL below from crontab (UNIX to
&
Jie Liang,
PostgreSQL needs to keep track of you 3 million updates
until you perform a commit.
So one way to avoid the WAL contention is to use a FOR
loop and issuing a commit every 1,000 records or so.
Regards,
Nikolaus Dilger
Jie Liang wrote:
>
> Tom,
>
> I tried to update
exes were a new feature in Oracle 8i.
So its a relatively new feature in flagship comercial
database. And you would get the same poor performance
without the functional index in Oracle.
Regards,
Nikolaus
On Wed, 18 September 2002, Laurette Cisneros wrote:
>
> Yes, indeed.
>
&g
= 20 seconds
for the network roundtrips. Most likely the network
roundtrip is longer. Instead of a single ping you
would need to compare 20,000 network roundtrips without
database access.
And you should use a valid SQL statement if you want to
do a serious database test.
Regards,
Nikolaus
p clean up the staging tables no longer
needed:
DROP TABLE unique_sessions;
DROP TABLE new_sessions;
TRUNCATE TABLE raw_data;
Regards,
Nikolaus
On Thu, 06 June 2002, "Nicolas Nolst" wrote
>
>
> Hi all,I have developped a perl
script to populate a database with two tables:
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