[GENERAL] Shared Buffers
Hello All, How Postgres Maintains data in Shared Buffer Does It maintains queried data in memory or table data and Next time how postgres fetch data from memory rather than disk Which algorithm is used for storing data how data is indexed in shared buffers Thanks Siddharth
[GENERAL] pg_xlog content
Hi, When I initialize database, pg_xlog direcory takes almost 17 MB size Why pg_xlog/WAL takes 17 MB of size while there is no transaction occurred ? What is the content of pg_xlog , If it's only wal file it's must be blank after on write of transaction on database. regards, Siddharth -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] pg_xlog content
Richard Huxton wrote: Siddharth Shah wrote: Hi, When I initialize database, pg_xlog direcory takes almost 17 MB size Why pg_xlog/WAL takes 17 MB of size while there is no transaction occurred ? What is the content of pg_xlog , If it's only wal file it's must be blank after on write of transaction on database. It's the WAL. Files will be 16MB in size and you will have several (I think 3 is the minimum). If you have a large update that can increase. See the checkpoint_segments setting if you think that's something you'll do frequently. If you are using WAL-based replication you could have lots if the archive command keeps failing. I am not using wall based replication ? I no not have frequent long transaction , need of checkpoints Just want to get what data resides in pg_xlog that it takes 16MB without any transactions. -Siddharth -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] pg_xlog content
Albe Laurenz wrote: Siddharth Shah wrote: I am not using wall based replication ? I no not have frequent long transaction , need of checkpoints Just want to get what data resides in pg_xlog that it takes 16MB without any transactions. It contains the transaction log files. The files are precreated with a size of 16MB and filled with log entries. There will normally be several of those files around. Since your main objective is to keep size small, you can change the default of 16MB by setting XLOG_SEG_SIZE in src/include/pg_config_manual.h to a smaller value. Yours, Laurenz Albe Thanks for info, will help me. Yes, Objective is to reduce the size, Does setting XLOG_SEG_SIZE to lower size make any difference in performance. Is there any content other than log that that postgres refers from pg_xlog regards, Siddharth -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] configure options
Albe Laurenz wrote: Siddharth Shah wrote: I am compiling postgres, I have some doubts on ./configure options --enable-nls[=LANGUAGES] enable Native Language Support Do I need to supply each language name which i am going to store in my database or just have to take support UTF-8 ? You need to have support for the locale which you want to use for character sorting, case conversion and character classification (set at "initdb" time) as well as support for the locale in which you want server messages to be, and for the one you want for date and numeric formatting. You don't have to include support for all languages you store in the database (but the database should then use UTF-8 as server encoding). and --disable-largefile Does it refers to for storing blob objects to store or anything else ? I couldn't find this configure switch in the documentation for 8.3 or 8.4. Can you explain where you found it and which version you are using? Yours, Laurenz Albe I am using 8.3.5 and I have found these options in configure help ./configure --help -Siddharth
Re: [GENERAL] configure options
Albe Laurenz wrote: Siddharth Shah wrote: I am compiling postgres, I have some doubts on ./configure options --disable-largefile Does it refers to for storing blob objects to store or anything else ? I couldn't find this configure switch in the documentation for 8.3 or 8.4. Can you explain where you found it and which version you are using? I am using 8.3.5 and I have found these options in configure help ./configure --help I see. It seems to be missing in the documentation. This has nothing to do with large objects. This disables use of the large file API for operating system files. If you disable this, you will probably not be able to use operating system files that exceed 2GB in size, which PostgreSQL normally does not do anyway. My recommendation is to leave this switch alone and use the default; you should not encounter any problems. Yours, Laurenz Albe In My Application I have only 256MB storage device and I have to manage many other application in same storage So, have to remove use less files , From configuration disabling unwanted options helps to reduce the size. So, I need detail description on compile options and postgres installation files. If this is provided then will help me. -Siddharth -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] configure options
Albe Laurenz wrote: Siddharth Shah wrote: In My Application I have only 256MB storage device and I have to manage many other application in same storage So, have to remove use less files , From configuration disabling unwanted options helps to reduce the size. So, I need detail description on compile options and postgres installation files. If this is provided then will help me. I don't think that --disable-largefile will reduce the size of the PostgreSQL executables noticably, if at all. It will certainly not reduce the amount of disk space required for your database. Do you only need the PostgreSQL client or also the server? Will that small storage device also contain the database? Yes, I need to run Client Server both application.Yes database reside in same storage Will small size make any issue ? Reducing the number of languages with --enable-nls=languages will certainly help some. Disable all Optional Packages you don't need (they should be described in the documentation). At this time problem is If I want to support some new foreign language in future on deployed machine. Will it support, while I configured postgres with specific language option. Documentation on these parameters from postgres appreciable Yours, Laurenz Albe -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
Re: [GENERAL] configure options
Tom Lane wrote: Siddharth Shah [EMAIL PROTECTED] writes: In My Application I have only 256MB storage device and I have to manage many other application in same storage Quite honestly, you're going to need some other database besides Postgres if you need a disk footprint that's only a fraction of 256MB. It's just not designed for that. Maybe sqllite or bdb would be closer to what you need. regards, tom lane Hi Tom, I have explored SQLite DBD but they have limitations on concurrency My Requirement falls In between lighter enterprise databases So finally concluded postgres, My database size on pg is almost 12 MB Does any cons which I am going to face with pg with slower size then please mention. Transaction frequencies : more select queries than insert / update Almost 20 queries/sec is executing with current database. - Siddharth -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
[GENERAL] configure options
Hi, I am compiling postgres, I have some doubts on ./configure options --enable-nls[=LANGUAGES] enable Native Language Support Do I need to supply each language name which i am going to store in my database or just have to take support UTF-8 ? and --disable-largefile Does it refers to for storing blob objects to store or anything else ? - Siddharth -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
[GENERAL] Effect of stopped status collector process
Hello, I have started to explore PG, I have found pgstat.stat file taking too much write hits. As my need to deploy on flash based storage. I don't want higher I/O's To stop status collector process I have change postmaster.c by removing calls of pgstat.c Now every thing is working fine, Status collector process is not initiated ? Any drawbacks for not writing pgstat.stat ? Is there another way to achieve this or Will this create any problem like If pgstat.c is initiating some data structures which is shared to postmaster.c or else part - Siddharth. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
