Обсуждение: Multibyte or not?
Hello all, at the mysql-admin list I found a posting that says a non-multibyte built of the database would be faster than a multibyte one. My question is - do I always need a multibyte built if I plan to access the db with jdbc or do i only need it if the data is non-ascii? i know that java uses unicode but does that really matter unless I want to enter non-ascii letters? actually this came to my mind when I was in search for some tuning hints. I don't think this is the right place to ask this (would 'psql-admin' be that?) - but maybe one of you had similar problems? I am doing a lot of checking and inserting at runtime. while the java thread holds ~38Mb (~500Mb) it uses only 1.7% CPU (~900Hz). postgresql uses less than 4Mb at more than 90% CPU. I already doubled the effective cache size to be '2000' but that did not change anything. I wonder if the postgres would be faster if it would use more RAM. or is this the bottle neck's end (unless I get a better CPU)? thank you Chantal
Chantal, You probably should post this on the general list or the hackers list. Yes it will be faster with multibyte disabled since you will use have the number of bytes. However I don't think that you are going to get a really big bang for your buck there. AFAIK the biggest will be ram size or cache size, and disk speed. Dave -----Original Message----- From: pgsql-jdbc-owner@postgresql.org [mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Chantal Ackermann Sent: Wednesday, February 27, 2002 7:34 AM To: pgsql-jdbc@postgresql.org Subject: [JDBC] Multibyte or not? Hello all, at the mysql-admin list I found a posting that says a non-multibyte built of the database would be faster than a multibyte one. My question is - do I always need a multibyte built if I plan to access the db with jdbc or do i only need it if the data is non-ascii? i know that java uses unicode but does that really matter unless I want to enter non-ascii letters? actually this came to my mind when I was in search for some tuning hints. I don't think this is the right place to ask this (would 'psql-admin' be that?) - but maybe one of you had similar problems? I am doing a lot of checking and inserting at runtime. while the java thread holds ~38Mb (~500Mb) it uses only 1.7% CPU (~900Hz). postgresql uses less than 4Mb at more than 90% CPU. I already doubled the effective cache size to be '2000' but that did not change anything. I wonder if the postgres would be faster if it would use more RAM. or is this the bottle neck's end (unless I get a better CPU)? thank you Chantal ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org
hello Dave, hello all, I digged through psql-admin and found a link to the article by Bruce Momjian: "PostgreSQL Hardware Performance Tuning". There is some valuable information for me there. I will experiment for myself a bit before I bother some more people with my problem. If I get astonishing results I'll let you know... ;=) cheers Chantal > Chantal, > > You probably should post this on the general list or the hackers list. > Yes it will be faster with multibyte disabled since you will use have > the number of bytes. However I don't think that you are going to get a > really big bang for your buck there. > > AFAIK the biggest will be ram size or cache size, and disk speed. > > Dave > > -----Original Message----- > Hello all, > > at the mysql-admin list I found a posting that says a non-multibyte > built of > the database would be faster than a multibyte one. My question is - do I > > always need a multibyte built if I plan to access the db with jdbc or do > i > only need it if the data is non-ascii? i know that java uses unicode but > does > that really matter unless I want to enter non-ascii letters? > > actually this came to my mind when I was in search for some tuning > hints. I > don't think this is the right place to ask this (would 'psql-admin' be > that?) > - but maybe one of you had similar problems? > I am doing a lot of checking and inserting at runtime. while the java > thread > holds ~38Mb (~500Mb) it uses only 1.7% CPU (~900Hz). postgresql uses > less > than 4Mb at more than 90% CPU. I already doubled the effective cache > size to > be '2000' but that did not change anything. > > I wonder if the postgres would be faster if it would use more RAM. or is > this > the bottle neck's end (unless I get a better CPU)? > > thank you > Chantal > > ---------------------------(end of broadcast)--------------------------- > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org
Chantal, If you are using the 7.2 jdbc driver, you would only need to have multibyte support compiled into the server if you wanted to store multibyte characters. --Barry Chantal Ackermann wrote: > Hello all, > > at the mysql-admin list I found a posting that says a non-multibyte built of > the database would be faster than a multibyte one. My question is - do I > always need a multibyte built if I plan to access the db with jdbc or do i > only need it if the data is non-ascii? i know that java uses unicode but does > that really matter unless I want to enter non-ascii letters? > > actually this came to my mind when I was in search for some tuning hints. I > don't think this is the right place to ask this (would 'psql-admin' be that?) > - but maybe one of you had similar problems? > I am doing a lot of checking and inserting at runtime. while the java thread > holds ~38Mb (~500Mb) it uses only 1.7% CPU (~900Hz). postgresql uses less > than 4Mb at more than 90% CPU. I already doubled the effective cache size to > be '2000' but that did not change anything. > > I wonder if the postgres would be faster if it would use more RAM. or is this > the bottle neck's end (unless I get a better CPU)? > > thank you > Chantal > > ---------------------------(end of broadcast)--------------------------- > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org > >
Hi Barry, Is there any way I can check out if my installation has the multibyte support? Or anyone can tell the pre-compiled Red hatrpm package support multibyte or not? Thanks! Anthony > -----Original Message----- > From: pgsql-jdbc-owner@postgresql.org > [mailto:pgsql-jdbc-owner@postgresql.org]On Behalf Of Barry Lind > Sent: Wednesday, February 06, 2002 10:34 AM > To: chantal.ackermann@web.de > Cc: pgsql-jdbc@postgresql.org > Subject: Re: [JDBC] Multibyte or not? > > > Chantal, > > If you are using the 7.2 jdbc driver, you would only need to have > multibyte support compiled into the server if you wanted to store > multibyte characters. > > --Barry > > Chantal Ackermann wrote: > > Hello all, > > > > at the mysql-admin list I found a posting that says a > non-multibyte built of > > the database would be faster than a multibyte one. My question > is - do I > > always need a multibyte built if I plan to access the db with > jdbc or do i > > only need it if the data is non-ascii? i know that java uses > unicode but does > > that really matter unless I want to enter non-ascii letters? > > > > actually this came to my mind when I was in search for some > tuning hints. I > > don't think this is the right place to ask this (would > 'psql-admin' be that?) > > - but maybe one of you had similar problems? > > I am doing a lot of checking and inserting at runtime. while > the java thread > > holds ~38Mb (~500Mb) it uses only 1.7% CPU (~900Hz). postgresql > uses less > > than 4Mb at more than 90% CPU. I already doubled the effective > cache size to > > be '2000' but that did not change anything. > > > > I wonder if the postgres would be faster if it would use more > RAM. or is this > > the bottle neck's end (unless I get a better CPU)? > > > > thank you > > Chantal > > > > ---------------------------(end of broadcast)--------------------------- > > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org > > > > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/users-lounge/docs/faq.html >
Anthony Kwok wrote: > Is there any way I can check out if my installation has the multibyte support? Or anyone can tell the pre-compiled Redhat rpm package support multibyte or not? You could check with "select pg_encoding_to_char(1);" which is how the JDBC driver itself does it internally. If it gives 'EUC_JP' the backend has multibyte support, 'SQL_ASCII' means it hasn't. /Anders _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com