Re: [HACKERS] BEGIN inside transaction should be an error

2006-05-09 Thread Jaime Casanova
On 5/10/06, Tom Lane <[EMAIL PROTECTED]> wrote: Dennis Bjorklund <[EMAIL PROTECTED]> writes: > Yesterday I helped a guy on irc with a locking problem, he thought > that locking in postgresql was broken. It turned out that he had a PHP > function that he called inside his transaction and the funct

Re: [HACKERS] BEGIN inside transaction should be an error

2006-05-09 Thread Lukas Smith
Tom Lane wrote: Dennis Bjorklund <[EMAIL PROTECTED]> writes: Yesterday I helped a guy on irc with a locking problem, he thought that locking in postgresql was broken. It turned out that he had a PHP function that he called inside his transaction and the function did BEGIN and COMMIT. Since BEGIN

Re: [HACKERS] BEGIN inside transaction should be an error

2006-05-09 Thread Christopher Kings-Lynne
We could, but it'd probably break about as many apps as it fixed. I wonder whether php shouldn't be complaining about this, instead --- doesn't php have its own ideas about controlling where the transaction commit points are? All PHP does is when the connection is returned to the pool, if it is

Re: [HACKERS] BEGIN inside transaction should be an error

2006-05-09 Thread Tom Lane
Dennis Bjorklund <[EMAIL PROTECTED]> writes: > Yesterday I helped a guy on irc with a locking problem, he thought > that locking in postgresql was broken. It turned out that he had a PHP > function that he called inside his transaction and the function did BEGIN > and COMMIT. Since BEGIN inside a t

[HACKERS] BEGIN inside transaction should be an error

2006-05-09 Thread Dennis Bjorklund
Hi Yesterday I helped a guy on irc with a locking problem, he thought that locking in postgresql was broken. It turned out that he had a PHP function that he called inside his transaction and the function did BEGIN and COMMIT. Since BEGIN inside a transaction is just a warning what happend was th

Re: [HACKERS] Constraint Exclusion + Joins?

2006-05-09 Thread kris . shannon
On 5/2/06, Brandon Black <[EMAIL PROTECTED]> wrote: On 4/30/06, Heikki Linnakangas <[EMAIL PROTECTED]> wrote:> On Fri, 28 Apr 2006, Brandon Black wrote:>> > I dug around in CVS to have a look for this, and I did eventually find > > it (well, I found the corresponding docs patch that removed the not

[HACKERS] EXPLAIN verbose?

2006-05-09 Thread Cristiano Duarte
Does anyone know how to discover the tables (with schemas or oid) involved on a select statement? I tried EXPLAIN but it only reports the table names, not schemas or oid. I am developing a SNAPSHOT project for PostgreSQL called Pg::snapshots. It can be found here: http://cunha17.theicy.net/person

Re: [HACKERS] Number of dimensions of an array parameter

2006-05-09 Thread Bruce Momjian
Tom Lane wrote: > Bruce Momjian writes: > > Documentation updated to mention "dimmensions" are not enforced. > > This patch seems entirely pointless, since the point is already made > (with correct spelling even) in the very next line. Thanks, reverted. -- Bruce Momjian http://candle.pha.p

Re: [HACKERS] Need a help - Performance issues

2006-05-09 Thread Andrej Ricnik-Bay
On 5/10/06, Dhanaraj M <[EMAIL PROTECTED]> wrote: 2. walks through all known tuning parameters (in /etc/system and postgresql.conf) on the system 3. lists out what parameters are optimal/suboptimal for that platform, and makes recommendations. I thought that's why people still have DBAs ;}

[HACKERS] standard_conforming_strings vs escape_string_warning

2006-05-09 Thread Tom Lane
I see that in CVS head, if you turn on standard_conforming_strings, it still whines about backslashes: regression=# set standard_conforming_strings to 1; SET regression=# select '1234\5678'; WARNING: nonstandard use of escape in a string literal LINE 1: select '1234\5678'; ^ HINT:

Re: [HACKERS] Inheritance, Primary Keys and Foreign Keys

2006-05-09 Thread Simon Riggs
On Tue, 2006-05-09 at 01:20 +0200, Albert Cervera Areny wrote: > In my particular case (don't know about the SQL standard or other > cases), > it'd be enough if when an inherited table is created: > - A primary key in the inherited table is created with the same columns > as > the su

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread Tom Lane
PFC <[EMAIL PROTECTED]> writes: > Fun thing is, the rowcount from a temp table (which is the problem > here) > should be available without ANALYZE ; as the temp table is not concurrent, > it would be simple to inc/decrement a counter on INSERT/DELETE... No, because MVCC rules still appl

Re: [HACKERS] Number of dimensions of an array parameter

2006-05-09 Thread Tom Lane
Bruce Momjian writes: > Documentation updated to mention "dimmensions" are not enforced. This patch seems entirely pointless, since the point is already made (with correct spelling even) in the very next line. regards, tom lane ---(end of broadcas

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread PFC
> SELECT * FROM somewhere WHERE id IN (SELECT id FROM result) Well, you can either SELECT * FROM somewhere JOIN (SELECT id FROM result GROUP BY id) AS a USING (id); It's the same thing (and postgres knows it) You might want to use PL to store values, say PLperl, or even C

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread Dawid Kuroczko
On 5/9/06, PFC <[EMAIL PROTECTED]> wrote: > You might consider just selecting your primary key or a set of > primary keys to involved relations in your search query. If you > currently use "select *" this can make your result set very large. > > Copying all the result set to the temp. costs you

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread PFC
Does the time for commit change much if you leave out the analyze? Yes, when I don't ANALYZE the temp table, commit time changes from 30 ms to about 15 ms ; but the queries get horrible plans (see below) : Fun thing is, the rowcount from a temp table (which is the problem here) should

Re: [HACKERS] Compiling PL/Perl and Pl/Python on x86_64

2006-05-09 Thread imacat
On Mon, 08 May 2006 03:58:54 +0800 imacat <[EMAIL PROTECTED]> wrote: > On Sun, 07 May 2006 13:09:48 -0400 > Tom Lane <[EMAIL PROTECTED]> wrote: > > imacat <[EMAIL PROTECTED]> writes: > > > I cannot compile PL/Perl and PL/Python under x86_64. > > Works fine for me (without any tinkering with fla

Re: [HACKERS] Number of dimensions of an array parameter

2006-05-09 Thread Bruce Momjian
Documentation updated to mention "dimmensions" are not enforced. --- Stefan Kaltenbrunner wrote: > Thomas Hallgren wrote: > > I can create a function that takes a two dimension int array: > > > > CREATE FUNCTION twodims(in

Re: [PERFORM] [HACKERS] Big IN() clauses etc : feature proposal

2006-05-09 Thread PFC
Creating cursors for a simple plan like a single sequential scan is fast because it's using the original data from the table. I used the following query : SELECT * FROM bookmarks ORDER BY annonce_id DESC LIMIT 20 It's a backward index scan + limit... not a seq scan. And it's

Re: [HACKERS] Big IN() clauses etc : feature proposal

2006-05-09 Thread Greg Stark
PFC <[EMAIL PROTECTED]> writes: > > I really like this. It's clean, efficient, and easy to use. > > This would be a lot faster than using temp tables. > Creating cursors is very fast so we can create two, and avoid doing > twice the same work (ie. hashing the ids from the res

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread Tom Lane
PFC <[EMAIL PROTECTED]> writes: > Feature proposal : > A way to store query results in a named buffer and reuse them in the > next > queries. Why not just fix the speed issues you're complaining about with temp tables? I see no reason to invent a new concept. (Now, "just fix" mig

[HACKERS] Need a help - Performance issues

2006-05-09 Thread Dhanaraj M
I am currently looking at some performance issues. Our product uses the postgres as the backend and it uses a huge storage space. Is there a script available, which does the following: 1. When you point it to a postgres installation, -> 1.the script first identifies what platform (solaris

Re: [HACKERS] semaphore usage "port based"?

2006-05-09 Thread Max Khon
Hi! On Mon, Apr 03, 2006 at 11:56:13PM +0100, Robert Watson wrote: > >>This is why it's disabled by default, and the jail documentation > >>specifically advises of this possibility. Excerpt below. > > > >Ah, I see, glad to see it's accurately documented. > > As it has been for the last five ye

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread PFC
It would be interesting to know what the bottleneck is for temp tables for you. They do not go via the buffer-cache, they are stored in private memory in the backend, they are not xlogged. Nor flushed to disk on backend exit. They're about as close to in-memory tables as you're going to get...

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread Martijn van Oosterhout
On Tue, May 09, 2006 at 12:10:37PM +0200, PFC wrote: > Yes, but in this case temp tables add too much overhead. I wish > there were RAM based temp tables like in mysql. However I guess the > current temp table slowness comes from the need to mark their existence in > the system ca

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread PFC
Additionally to your query you are already transferring the whole result set multiple times. First you copy it to the result table. Then you read it again. Your subsequent queries will also have to read over all the unneeded tuples just to get your primary key. Considering that the resul

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread Christian Kratzer
Hi, On Tue, 9 May 2006, PFC wrote: You might consider just selecting your primary key or a set of primary keys to involved relations in your search query. If you currently use "select *" this can make your result set very large. Copying all the result set to the temp. costs you additional I

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread Christian Kratzer
Hi, On Tue, 9 May 2006, PFC wrote: Back to the point : I can't use the temp table method, because temp tables are too slow. Creating a temp table, filling it, analyzing it and then dropping it takes about 100 ms. The search query, on average, takes 10 ms. just some thoughts: You might con

Re: [HACKERS] [PERFORM] Big IN() clauses etc : feature proposal

2006-05-09 Thread PFC
You might consider just selecting your primary key or a set of primary keys to involved relations in your search query. If you currently use "select *" this can make your result set very large. Copying all the result set to the temp. costs you additional IO that you propably dont need. It i

[HACKERS] Big IN() clauses etc : feature proposal

2006-05-09 Thread PFC
The moral of the story is that you're probably better off running a bunch of small selects than in trying to optimize things with one gargantuan select. Ever experiment with loading the parameters into a temp table and joining to that? Also, it might be worth re-testing that conclusion with