Re: [PERFORM] Performance pb vs SQLServer.
> ["very, very offtopic"] > Ok. This comparition is just as useless as the other one, > because it's comparing oranges with apples (It's funny > anyway). I was just choosing an example in which you can see > the best of postgresql against 'not so nice' behavior of > mssql2000 (no service pack, it's my desktop system, I'll do > the same test later with SP4 and different isolation levels > and I'll check results). There will be no difference in the service packs. SQL 2005 has "MVCC" (they call it something different, of course, but that's basicallyi what it is) > Furthermore, MSSQL2000 is 5 years > old now. Does anybody has the same cellular phone, or > computer? (I don't want to know :-) ). The big question is There is a big difference between your database and your cellphone. There are a lot of systems out there running very solidly on older products like MSSQL 7 (probably even some on 6.x), as well as Oracle 7,8 and 9... I'd say there is generally a huge difference in reliabilty in your cellphone hw/sw than there is in your db hw/sw. I have yet to see a cellphone that can run for a year without a reboot (or with a lot of brands, complete replacement). //Magnus ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
Re: [PERFORM] Performance pb vs SQLServer.
> Hi, > > I have a perfomance issue : > > I run PG (8.0.3) and SQLServer2000 on a Windows2000 Server > (P4 1,5Ghz 512Mo) I have a table (320 rows) and I run > this single query : > > select cod from mytable group by cod > I have an index on cod (char(4) - 88 different values) > > PG = ~ 20 sec. > SQLServer = < 8 sec > > > the explain is : > > HashAggregate (cost=64410.09..64410.09 rows=55 width=8) > -> Seq Scan on mytable (cost=0.00..56325.27 rows=3233927 width=8) > > > if I switch to "enable_hashagg = false" (just for a try...) > the planner will choose my index : > > Group (cost=0.00..76514.01 rows=55 width=8) > -> Index Scan using myindex on mytable > (cost=0.00..68429.20 rows=3233927 > width=8) > > but performance will be comparable to previous test. > > So with or without using Index I have the same result. Out of curiosity, what plan do you get from SQLServer? I bet it's a clustered index scan... //Magnus ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [PERFORM] Odd Locking Problem
On Thu, 11 Aug 2005 16:11:58 -0500, John A Meinel <[EMAIL PROTECTED]> wrote: >the insert is occurring into table 'a' not table 'b'. >'a' refers to other tables, but these should not be modified. So your "a" is Alvaro's "b", and one of your referenced tables is Alvaro's "a". This is further supported by the fact that the problem doesn't occur with 8.1. Servus Manfred ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [PERFORM] Performance pb vs SQLServer.
On Mon, Aug 15, 2005 at 10:25:47AM +0200, Magnus Hagander wrote: > SQL 2005 has "MVCC" (they call it something different, of course, but > that's basicallyi what it is) Interesting; do they use an overwriting storage manager like Oracle, or a non-overwriting one like Postgres? -- Alvaro Herrera () "The Postgresql hackers have what I call a "NASA space shot" mentality. Quite refreshing in a world of "weekend drag racer" developers." (Scott Marlowe) ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [PERFORM] I'm configuraing a new system (Bigish) and need some advice.
7.4 is the pg version BTWgoing to switch to 8 if it's worth it. Ingrate, n.: A man who bites the hand that feeds him, and then complains of indigestion. -- "Don't say yes until I finish talking." -- Darryl F. Zanuck -- "Don't say yes until I finish talking." -- Darryl F. Zanuck ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
[PERFORM] choosing RAID level for xlogs
Hi, One simple question. For 125 or more checkpoint segments (checkpoint_timeout is 600 seconds, shared_buffers are at 21760 or 170MB) on a very busy database, what is more suitable, a separate 6 disk RAID5 volume, or a RAID10 volume? Databases will be on separate spindles. Disks are 36GB 15KRPM, 2Gb Fiber Channel. Performance is paramount, but I don’t want to use RAID0. PG7.4.7 on RHAS 4.0 I can provide more info if needed. Appreciate some recommendations! Thanks, Anjan ---This email message and any included attachments constitute confidential and privileged information intended exclusively for the listed addressee(s). If you are not the intended recipient, please notify Vantage by immediately telephoning 215-579-8390, extension 1158. In addition, please reply to this message confirming your receipt of the same in error. A copy of your email reply can also be sent to [EMAIL PROTECTED] Please do not disclose, copy, distribute or take any action in reliance on the contents of this information. Kindly destroy all copies of this message and any attachments. Any other use of this email is prohibited. Thank you for your cooperation. For more information about Vantage, please visit our website at http://www.vantage.com.---
