Re: [HACKERS] [GENERAL] Checkpoint request failed on version 8.2.1.

2007-01-15 Thread Tom Lane
"Takayuki Tsunakawa" <[EMAIL PROTECTED]> writes: > BTW, why does the bgwriter try to open and write the pages of already > dropped relations? It does not; the problem is with stale fsync requests. > If the relation being dropeed has > already been registered in the list of files to be fsynced, is

Re: [GENERAL] Improve Postgres Query Speed

2007-01-15 Thread Tom Lane
"carter ck" <[EMAIL PROTECTED]> writes: > And you are definitely right when updating the table. The time it takes is > getting longer and longer. When I do a select statement, the speed has also > degraded. Seems like you need a VACUUM in there somewhere... regards, tom

Re: [GENERAL] Reserve a value in a serial type field

2007-01-15 Thread A. Kretschmer
am Mon, dem 15.01.2007, um 10:57:17 -0800 mailte Albert folgendes: > Hi all. I have this issue: I need to load a value for an integer field > (with auto increment) which I implemented with a serial type and to > avoid inserts with that value in this field. The task is for a > distributed program I

Re: [GENERAL] Improve Postgres Query Speed

2007-01-15 Thread Chris
carter ck wrote: Hi, the rpt_generated is a boolean value. And you are definitely right when updating the table. The time it takes is getting longer and longer. When I do a select statement, the speed has also degraded. If you send us the query that is slow, then I'm sure you'll get some s

Re: [GENERAL] Collating Question...

2007-01-15 Thread Michael Glaesemann
On Jan 16, 2007, at 11:52 , Jerry LeVan wrote: The locale function on the mac has everything set to "C" and on the linux box it is all "en_US.UTF-8". Is there a simple way to get the collating sequences to be the same on both boxen? My understanding is that to have the same ordering you need

[GENERAL] Collating Question...

2007-01-15 Thread Jerry LeVan
Hi, I am running 8.2.1 on my Mac OS X and my X86 Fedora Laptop... I just noticed that on my mac: levan=# select 'A' < 'a' ; ?column? -- t (1 row) and on the linux box: levan=# select 'A' < 'a' ; ?column? -- f (1 row) The locale function on the mac has everything set to "C" a

Re: [GENERAL] Improve Postgres Query Speed

2007-01-15 Thread Jorge Godoy
"carter ck" <[EMAIL PROTECTED]> writes: > Hi, the rpt_generated is a boolean value. Is there any special reason, then, for not using a boolean type? > And you are definitely right when updating the table. The time it takes is > getting longer and longer. When I do a select statement, the speed

Re: [GENERAL] Linking tables and indexes

2007-01-15 Thread Jorge Godoy
Alvaro Herrera <[EMAIL PROTECTED]> writes: > If you're in 8.1 or better, I'd suggest defining only two indexes, one I'm on 8.1. Waiting for SuSE to update to 8.2... ;-) > on (ci_id) and other on (document_client_id), and let the system deal > with mixing them using the bitmap scan technique w

Re: [GENERAL] Improve Postgres Query Speed

2007-01-15 Thread carter ck
Hi, the rpt_generated is a boolean value. And you are definitely right when updating the table. The time it takes is getting longer and longer. When I do a select statement, the speed has also degraded. Thanks. From: Jorge Godoy <[EMAIL PROTECTED]> To: "carter ck" <[EMAIL PROTECTED]> CC: [

Re: [GENERAL] Linking tables and indexes

2007-01-15 Thread Alvaro Herrera
Jorge Godoy wrote: > Thinking about how PostgreSQL is able to use composed indices should I create > the reverse index ("CREATE INDEX something ON ged.documents_clients_cis > (document_client_id, ci_id)") or I'd only be wasting disk and processing? > > The query can be done from either side (i.e.

Re: [HACKERS] [GENERAL] Checkpoint request failed on version 8.2.1.

2007-01-15 Thread Takayuki Tsunakawa
From: "Magnus Hagander" <[EMAIL PROTECTED]> > But yeah, that's probably a good idea. A quick look at the code says we > should at least ask people who have this problem to give it a run with > logging at DEBUG5 which should then log exactly what the errorcode was. > Or are you seeing more places th

Re: [GENERAL] Improve Postgres Query Speed

2007-01-15 Thread Jorge Godoy
"carter ck" <[EMAIL PROTECTED]> writes: > Hi, > > Thanks for reminding me. And the actual number of records is 100,000. > > The table is as following: You forgot the EXPLAIN ANALYZE output... > Table my_messages > > mid

Re: [GENERAL] Improve Postgres Query Speed

2007-01-15 Thread Alvaro Herrera
carter ck wrote: > > Hi, > > Thanks for reminding me. And the actual number of records is 100,000. > > The table is as following: And the query? -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support

Re: [GENERAL] Transaction callback

2007-01-15 Thread Jorge Godoy
Kevin Field <[EMAIL PROTECTED]> writes: > http://archives.postgresql.org/pgsql-hackers/2004-01/msg00861.php > > (Just to dredge up another old thread...) > >> While its true that a post-commit operation cannot modify a database, it >> might still for instance propagate the outcome of the transacti

Re: [GENERAL] Improve Postgres Query Speed

2007-01-15 Thread carter ck
Hi, Thanks for reminding me. And the actual number of records is 100,000. The table is as following: Table my_messages midx | integer| not null default nextval('public.my_

Re: [GENERAL] Transaction callback

2007-01-15 Thread Kevin Field
http://archives.postgresql.org/pgsql-hackers/2004-01/msg00861.php (Just to dredge up another old thread...) While its true that a post-commit operation cannot modify a database, it might still for instance propagate the outcome of the transaction to another resource outside of the database, it

[GENERAL] Linking tables and indexes

2007-01-15 Thread Jorge Godoy
Hi! I'm not sure about the English terminology for that so I'm sorry if I made a mistake on the subject and on this message. I hope de code explains it better if I missed it :-) I have some tables that will have N:M relationships between themselves and for that I created some linking tables su

Re: [GENERAL] Improve Postgres Query Speed

2007-01-15 Thread Chad Wagner
On 1/15/07, carter ck <[EMAIL PROTECTED]> wrote: I am having slow performance issue when querying a table that contains more than 1 records. Everything just slow down when executing a query though I have created Index on it. You didn't really provide much information for anyone to help y

[GENERAL] Improve Postgres Query Speed

2007-01-15 Thread carter ck
Hi all, I am having slow performance issue when querying a table that contains more than 1 records. Everything just slow down when executing a query though I have created Index on it. Can anyone suggest ways to improve the speed? Thanks. ___

Re: [GENERAL] PQexec does not return.

2007-01-15 Thread Steve Martin
Hi All, Found the problem. This was caused by a memory leak in our application. Regards Steve Martin Steve Martin wrote: Hi All, We have an intermittent problem where PQexec does not seem to return even though the server seems to have sent the results. From the gdb output , the sql sta

Re: [GENERAL] substr negative indexes

2007-01-15 Thread Guy Rouillier
Tom Lane wrote: and unless I'm mistaken, our behavior conforms to the spec and Oracle's doesn't. Strictly speaking, the spec doesn't define the behavior of "SUBSTR" at all, only "SUBSTRING" with this weird FROM/FOR argument syntax. But PG treats SUBSTR(x,y,z), SUBSTRING(x,y,z) and SUBSTRING(x F

Re: [GENERAL] Reserve a value in a serial type field

2007-01-15 Thread Albert
Thanks Shane. I solved taking trace of the sequence value directly in the program...it is not a good solution but it works until I find a better one! ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archiv

Re: [GENERAL] Reserve a value in a serial type field

2007-01-15 Thread Shane Ambler
Albert wrote: Hi all. I have this issue: I need to load a value for an integer field (with auto increment) which I implemented with a serial type and to avoid inserts with that value in this field. The task is for a distributed program I'm creating and I wonder if there is an efficient solution f

Re: [GENERAL] Avoiding empty queries in tsearch

2007-01-15 Thread Oleg Bartunov
Doug, numnode exists for sure ! It's plainto_tsquery function which Teodor used in example, appeared in 8.2 Oleg On Mon, 15 Jan 2007, Doug Cole wrote: That sounds perfect, but it doesn't seem to exist on either of the postgresql installations I have access to (8.1 on ubuntu and fedora core).

Re: [GENERAL] Avoiding empty queries in tsearch

2007-01-15 Thread Teodor Sigaev
Doug Cole wrote: That sounds perfect, but it doesn't seem to exist on either of the postgresql installations I have access to (8.1 on ubuntu and fedora core). Is it new to 8.2? Is there a similar function under 8.1, or at Yes, it's new in 8.2 least a decent work-around? Thanks for the h

Re: [GENERAL] Avoiding empty queries in tsearch

2007-01-15 Thread Doug Cole
That sounds perfect, but it doesn't seem to exist on either of the postgresql installations I have access to (8.1 on ubuntu and fedora core). Is it new to 8.2? Is there a similar function under 8.1, or at least a decent work-around? Thanks for the help, Doug On 1/15/07, Teodor Sigaev <[EMAIL

[GENERAL] Reserve a value in a serial type field

2007-01-15 Thread Albert
Hi all. I have this issue: I need to load a value for an integer field (with auto increment) which I implemented with a serial type and to avoid inserts with that value in this field. The task is for a distributed program I'm creating and I wonder if there is an efficient solution for it. I though

Re: [GENERAL] Glacially slow nested SELECT

2007-01-15 Thread Tom Lane
Demitri Muna <[EMAIL PROTECTED]> writes: > On 15 Jan 2007, at 16:21, Tom Lane wrote: >> It looks like spview is a view with an embedded ORDER BY? IIRC that >> prevents any meaningful optimization of joins to it --- and >> WHERE-IN-sub-SELECT is a kind of join. > Thanks for the pointer Tom; removi

Re: [HACKERS] [GENERAL] Checkpoint request failed on version 8.2.1.

2007-01-15 Thread Tom Lane
Magnus Hagander <[EMAIL PROTECTED]> writes: > Tom Lane wrote: >> DEBUG5 is going to be a bit voluminous, but let's try that if we can. > Perhaps we should switch down the DEBUG level of it, at least until we > know what happens? That would have to wait on another update release, or at least someo

Re: [GENERAL] Glacially slow nested SELECT

2007-01-15 Thread Demitri Muna
On 15 Jan 2007, at 16:21, Tom Lane wrote: [EMAIL PROTECTED] writes: I have a query that is extraordinarily slow but I don't know why. It looks like spview is a view with an embedded ORDER BY? IIRC that prevents any meaningful optimization of joins to it --- and WHERE-IN-sub-SELECT is a kind

Re: [HACKERS] [GENERAL] Checkpoint request failed on version 8.2.1.

2007-01-15 Thread Magnus Hagander
Tom Lane wrote: > Magnus Hagander <[EMAIL PROTECTED]> writes: >> But yeah, that's probably a good idea. A quick look at the code says we >> should at least ask people who have this problem to give it a run with >> logging at DEBUG5 which should then log exactly what the errorcode was. >> Or are you

Re: [HACKERS] [GENERAL] Checkpoint request failed on version 8.2.1.

2007-01-15 Thread Tom Lane
Magnus Hagander <[EMAIL PROTECTED]> writes: > But yeah, that's probably a good idea. A quick look at the code says we > should at least ask people who have this problem to give it a run with > logging at DEBUG5 which should then log exactly what the errorcode was. > Or are you seeing more places th

Re: [HACKERS] [GENERAL] Checkpoint request failed on version 8.2.1.

2007-01-15 Thread Magnus Hagander
Tom Lane wrote: > Magnus Hagander <[EMAIL PROTECTED]> writes: >> Tom Lane wrote: >>> pg_control is certainly not ever deleted or renamed, and in fact I >>> believe there's an LWLock enforcing that only one PG process at a time >>> is even touching it. So we need another theory to explain this one

Re: [GENERAL] Unpredicatable behavior of volatile functions used

2007-01-15 Thread Aleksander Kmetec
Tom Lane wrote: Aleksander Kmetec <[EMAIL PROTECTED]> writes: Some quick testing shows that util.row_number() only gets re-evaluated at every call if the subquery contains an ORDER BY clause. Now we can predict whether we need to compensate for that just by looking at the original query. If y

[GENERAL] NOTIFY QUESTION

2007-01-15 Thread Oisin Glynn
From the Docs see below it implies that the WHERE clause of the update is ignored.( http://www.postgresql.org/docs/8.1/static/sql-createrule.html ) If I create a Rule as CREATE RULE foo_update_false AS ON UPDATE TO foo WHERE NEW.some_flag = TRUE DO NOTIFY foo_update; Does the WHERE clause

Re: [GENERAL] Why the data changes it's value by itself!

2007-01-15 Thread Ardian Xharra
Yes, the problem was the memory (testing with memtest) I took us long to have the machine check Thanks, - Original Message - From: "Richard Huxton" To: "Ardian Xharra" <[EMAIL PROTECTED]> Cc: "postgreSQL postgreSQL" Sent: Friday, November 17, 2006 1:12 PM Subject: Re: [GENERAL] Why t

Re: [GENERAL] Avoiding empty queries in tsearch

2007-01-15 Thread Teodor Sigaev
contrib_regression=# select numnode( plainto_tsquery('the any') ); NOTICE: query contains only stopword(s) or doesn't contain lexeme(s), ignored numnode - 0 (1 row) contrib_regression=# select numnode( plainto_tsquery('the table') ); numnode - 1 (1 row) contrib_r

Re: [GENERAL] Unpredicatable behavior of volatile functions used

2007-01-15 Thread Tom Lane
Aleksander Kmetec <[EMAIL PROTECTED]> writes: > Some quick testing shows that util.row_number() only gets re-evaluated at > every call if the subquery contains an ORDER > BY clause. Now we can predict whether we need to compensate for that just by > looking at the original query. If you're goin

Re: [GENERAL] Glacially slow nested SELECT

2007-01-15 Thread Tom Lane
[EMAIL PROTECTED] writes: > I have a query that is extraordinarily slow but I don't know why. It looks like spview is a view with an embedded ORDER BY? IIRC that prevents any meaningful optimization of joins to it --- and WHERE-IN-sub-SELECT is a kind of join. regards, to

Re: [GENERAL] Autovacuum Improvements

2007-01-15 Thread Alban Hertroys
Pavan Deolasee wrote: > Simon Riggs wrote: >> On Fri, 2006-12-29 at 20:25 -0300, Alvaro Herrera wrote: >>> Christopher Browne wrote: >>> Seems to me that you could get ~80% of the way by having the simplest "2 queue" implementation, where tables with size < some threshold get thrown

Re: [GENERAL] Unpredicatable behavior of volatile functions used

2007-01-15 Thread Aleksander Kmetec
Tom Lane wrote: This isn't gonna work very well if your query involves sorting, because the SELECT-list is evaluated before the sort step ... regards, tom lane Thanks, this seems to solve my problem. Some quick testing shows that util.row_number() only gets re-evalua

Re: [GENERAL] check table existence...

2007-01-15 Thread Alban Hertroys
Shoaib Mir wrote: > Something like this will help you.. Or shorter: > === > > CREATE OR REPLACE FUNCTION public.check_table(varchar, varchar) > RETURNS boolean AS $$ > DECLARE > v_cnt integer; > v_tbl boolean; > BEGIN PERFORM 1 FROM pg_tables where tablename = $1

[GENERAL] Glacially slow nested SELECT

2007-01-15 Thread thatsanicehatyouhave
Hello all, I have a query that is extraordinarily slow but I don't know why. It crosses a many-to-many join table and looks like this: SELECT * FROM spview WHERE id IN (SELECT signal_profile_id FROM track_to_signal_profile WHERE track_id = 19510985); The three tables are: track <-> track

Re: [GENERAL] Unpredicatable behavior of volatile functions used in cursors

2007-01-15 Thread Tom Lane
Aleksander Kmetec <[EMAIL PROTECTED]> writes: > We're using the following technique for counting the number of rows in a > cursor: > DECLARE instance_cur_1 SCROLL CURSOR FOR > SELECT util.row_number(), * > FROM ( > $LONG_RUNNING_QUERY > ) ss > FETCH LAST IN instance_cur_1; > util.row_number

Re: [GENERAL] Runtime error when calling function from .NET ( Function returns record)

2007-01-15 Thread Tom Lane
dparent <[EMAIL PROTECTED]> writes: > I have a function which returns TYPE RECORD and receives a string. The passed > string is used to build a dynamic SQL statement and the passed string is the > SELECT LIST of the built dynamic SQL statement. > The call works fine from Postgres SQL (PL/PG SQL) b

[GENERAL] Unpredicatable behavior of volatile functions used in cursors

2007-01-15 Thread Aleksander Kmetec
Hi, I'm running into some inconsistent behavior when using volatile functions with cursors under PG 8.1. We're using the following technique for counting the number of rows in a cursor: --- DECLARE instance_cur_1 SCROLL CURSOR FOR SELECT util.row_number(), * FROM ( $LONG_RUNNIN

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Shane Ambler
Jan van der Weijde wrote: That is exactly the problem I think. However I do not deliberately retrieve the entire table. I use the default settings of the PostgreSQL You will want to increase the default settings and let PostgreSQL use as much RAM as you have - especially when retrieving a larg

Re: [GENERAL] like query backslash

2007-01-15 Thread ksherlock
Sim Zacks wrote: > To retrieve the above example, I needed to query: > select * from filetable where filename like 'serverdir%' > > Is this a bug or is there a reason for this? > > Sim There's a reason. With like queries, if you want to search for the literal characters % or ? they

[GENERAL] Avoiding empty queries in tsearch

2007-01-15 Thread Doug Cole
I am having trouble with to_tsquery when the query is all stop words. Rather than return everything as a match, it returns nothing with the notice: NOTICE: Query contains only stopword(s) or doesn't contain lexem(s), ignored What is the best way to check for this, I was hoping to be able to che

Re: [GENERAL] Autovacuum Improvements

2007-01-15 Thread Pavan Deolasee
Simon Riggs wrote: > On Fri, 2006-12-29 at 20:25 -0300, Alvaro Herrera wrote: >> Christopher Browne wrote: >> >>> Seems to me that you could get ~80% of the way by having the simplest >>> "2 queue" implementation, where tables with size < some threshold get >>> thrown at the "little table" queue,

Re: [GENERAL] index type for indexing long texts

2007-01-15 Thread Aleksander Kmetec
Thank you both for your suggestions. I think I'll try the GiST approach first since using an existing contrib extension as a starting point seems like a simpler task for someone like me. :) Regards, Aleksander Richard Troy wrote: Aleksander Kmetec <[EMAIL PROTECTED]> writes: I'm looking f

[GENERAL] Runtime error when calling function from .NET ( Function returns record)

2007-01-15 Thread dparent
I have a function which returns TYPE RECORD and receives a string. The passed string is used to build a dynamic SQL statement and the passed string is the SELECT LIST of the built dynamic SQL statement. The call works fine from Postgres SQL (PL/PG SQL) but when I make the call from .NET (Core lab

Re: [GENERAL] Backup the part of postgres database

2007-01-15 Thread btober
Joshua D. Drake wrote: roopa perumalraja wrote: Thanks a lot for your immediate reply. can you please tell me how to use the command pg_dump to backup specific tables. Thanks a lot in advance. pg_dump --help Better yet, try this first: "http://www.catb.org/~esr/faqs/smart-questions.html";

Re: [GENERAL] check table existence...

2007-01-15 Thread Moritz Bayer
Thanks, that's exactly what I was looking for :-) kind regards, Morirt 2007/1/15, A. Kretschmer <[EMAIL PROTECTED]>: am Mon, dem 15.01.2007, um 13:18:11 +0100 mailte Moritz Bayer folgendes: > Dear list, > > I would like to create a function which gets a tablename and checks if the > specifi

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Shoaib Mir
An old post on the archives might help you --> http://archives.postgresql.org/pgsql-interfaces/2005-11/msg00010.php that was an attempt to simulate functionality similar to setFetchSize in JDBC. --- Shoaib Mir EnterpriseDB (www.enterprisedb.com) On 1/15/07, Jan van der Weijde <[EMAIL

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Gregory S. Williamson
Limit is somewhat magical ... at least to a degree. Not sure about cursors since I am not currently using them. select count(*) from bill_rpt_work; count - 2317451 (1 row) Time: 1709.829 ms billing=# \d bill_rpt_work Table "reporting.bill_rpt_work" Column |

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Richard Huxton
Jan van der Weijde wrote: That is exactly the problem I think. However I do not deliberately retrieve the entire table. I use the default settings of the PostgreSQL installation and just execute a simple SELECT * FROM table. I am using a separate client and server (both XP in the test environme

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Jan van der Weijde
Unfortunately a large C program has already been written.. But if a function like PQsetFetchSize() was available in libpq, that would also solve the problem. From: Shoaib Mir [mailto:[EMAIL PROTECTED] Sent: Monday, January 15, 2007 13:49 To: Jan van der Weijde Cc

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Shoaib Mir
If you go with Java, you can make it faster by using setFetchSize (JDBC functionality) from client and that will help you with the performance in case of fetching large amounts of data. --- Shoaib Mir EnterpriseDB (www.enterprisedb.com) On 1/15/07, Jan van der Weijde <[EMAIL PROTECT

Re: [GENERAL] check table existence...

2007-01-15 Thread Shoaib Mir
Something like this will help you.. === CREATE OR REPLACE FUNCTION public.check_table(varchar, varchar) RETURNS boolean AS $$ DECLARE v_cnt integer; v_tbl boolean; BEGIN SELECT count(1) INTO v_cnt FROM pg_tables where tablename = $1 and schemaname = $2; IF v_cnt

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Jan van der Weijde
That is exactly the problem I think. However I do not deliberately retrieve the entire table. I use the default settings of the PostgreSQL installation and just execute a simple SELECT * FROM table. I am using a separate client and server (both XP in the test environment), but that should not make

Re: [GENERAL] check table existence...

2007-01-15 Thread Alban Hertroys
A. Kretschmer wrote: > am Mon, dem 15.01.2007, um 13:18:11 +0100 mailte Moritz Bayer folgendes: >> Dear list, >> >> I would like to create a function which gets a tablename and checks if the >> specific table exists.The return value should be a bool. >> Now I'm wondering how to do this the best

Re: [GENERAL] check table existence...

2007-01-15 Thread A. Kretschmer
am Mon, dem 15.01.2007, um 13:18:11 +0100 mailte Moritz Bayer folgendes: > Dear list, > > I would like to create a function which gets a tablename and checks if the > specific table exists.The return value should be a bool. > Now I'm wondering how to do this the best way. > > Any suggestions?

[GENERAL] check table existence...

2007-01-15 Thread Moritz Bayer
Dear list, I would like to create a function which gets a tablename and checks if the specific table exists.The return value should be a bool. Now I'm wondering how to do this the best way. Any suggestions? kind regards and thanks in advance, Moritz

[GENERAL] Persistent connections in PHP with PDO

2007-01-15 Thread Alan T. Miller
Has anyone played around with the new PHP ODO drivers and been able to successfully set up an object using persistent connections? I tried to follow the documentation in the PHP manual to send an array in the PDO constructor but receive a warning message that the underlying driver does not supp

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Alban Hertroys
Jan van der Weijde wrote: > Thank you. > It is true he want to have the first few record quickly and then > continue with the next records. However without LIMIT it already takes a > very long time before the first record is returned. > I reproduced this with a table with 1.1 million records on a

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Shoaib Mir
Oh yes, need to have a condition first for which you have partitioned tables. Only in that case it will work with partitions. --- Shoaib Mir EnterpriseDB (www.enterprisedb.com) On 1/15/07, Richard Huxton wrote: Shoaib Mir wrote: > You can also opt for partitioning the tables and t

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Richard Huxton
Jan van der Weijde wrote: Thank you. It is true he want to have the first few record quickly and then continue with the next records. However without LIMIT it already takes a very long time before the first record is returned. I reproduced this with a table with 1.1 million records on an XP mac

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Richard Huxton
Shoaib Mir wrote: You can also opt for partitioning the tables and this way select will only get the data from the required partition. Not in the case of SELECT * FROM though. Unless you access the specific partitioned table. On 1/15/07, Richard Huxton wrote: Jan van der Weijde wrote: >

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Jan van der Weijde
Thank you. It is true he want to have the first few record quickly and then continue with the next records. However without LIMIT it already takes a very long time before the first record is returned. I reproduced this with a table with 1.1 million records on an XP machine and in my case it took

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Shoaib Mir
You can also opt for partitioning the tables and this way select will only get the data from the required partition. -- Shoaib Mir EnterpriseDB (www.enterprisedb.com) On 1/15/07, Richard Huxton wrote: Jan van der Weijde wrote: > Hello all, > > one of our customers is using Postgre

Re: [GENERAL] Performance with very large tables

2007-01-15 Thread Richard Huxton
Jan van der Weijde wrote: Hello all, one of our customers is using PostgreSQL with tables containing millions of records. A simple 'SELECT * FROM ' takes way too much time in that case, so we have advised him to use the LIMIT and OFFSET clauses. That won't reduce the time to fetch millions

[GENERAL] Performance with very large tables

2007-01-15 Thread Jan van der Weijde
Hello all, one of our customers is using PostgreSQL with tables containing millions of records. A simple 'SELECT * FROM ' takes way too much time in that case, so we have advised him to use the LIMIT and OFFSET clauses. However now he has a concurrency problem. Records deleted, added or updated

Re: [GENERAL] Backup the part of postgres database

2007-01-15 Thread Shoaib Mir
COPY command might also help COPY (SELECT * FROM country WHERE country_name LIKE 'A%') TO '/usr1/proj/bray/sql/a_list_countries.copy'; Details can be found at --> http://www.postgresql.org/docs/current/static/sql-copy.html -- Shoaib Mir EnterpriseDB (www.enterprisedb.com) O