Thread: clarification of postgres limitations
According to the official documentation: ------------------------------------------------------------------------- Limitations of PostgreSQL Maximum size for a database unlimited (4 TB databases exist) Maximum size for a table 16 TB on all operating systems Maximum size for a row 1.6 TB Maximum size for a field 1 GB Maximum number of rows in a table unlimited Maximum number of columns in a table 250 - 1600 depending on column types Maximum number of indexes on a table unlimited Of course, these are not actually unlimited, but limited to available disk space and memory/swap space. Performance may suffer when these values get unusually large. The maximum table size of 16 TB does not require large file support from the operating system. Large tables are stored as multiple 1 GB files so file system size limits are not important. The maximum table size and maximum number of columns can be increased if the default block size is increased to 32k. ------------------------------------------------------------------------- Since it seems that the location of the server's data store is bound to a single directory, a database cannot span across multiple file systems. Further, does it imply that the maxiumum size of a database cannot exceed the maximum size of the underlying file system? -- "Nothing is either good or bad, but thinking makes it so." -- Shakespeare -- Myron B Cheung (Soliton Associates) mailto: mbc@soliton.com
On Thursday 04 March 2004 12:35, mbc@soliton.com wrote: > > Limitations of PostgreSQL > Maximum size for a database unlimited (4 TB databases exist) > Maximum size for a table 16 TB on all operating systems > Since it seems that the location of the server's data store is bound to a > single directory, a database cannot span across multiple file systems. > Further, does it imply that the maxiumum size of a database cannot exceed > the maximum size of the underlying file system? If you're planning on having a database larger than your file-system supports, you might want to consider a different file-system. However... Each object (table, index) is stored in a separate file (more than one if split at 1GB). Some people use symlinks to move various files/directories to different locations. For example, to move the write-ahead-log to a different set of disks from the main DB files. Tablespaces are being worked on at the moment, so there is a good chance they will be in 7.5 -- Richard Huxton Archonet Ltd
On Thu, 4 Mar 2004 mbc@soliton.com wrote: > Since it seems that the location of the server's data store is bound to a > single directory, a database cannot span across multiple file systems. > Further, does it imply that the maxiumum size of a database cannot exceed > the maximum size of the underlying file system? With 7.5 you'll be able to easily put database structures on more than one file system. As of 7.x series, the initlocation script allowed you to put individual databases within a cluster on different storage points: http://www.postgresql.org/docs/7.4/static/manage-ag-alternate-locs.html
This is very good news. Thank you very much. On Thu, Mar 04, 2004 at 10:49:49AM -0700, scott.marlowe wrote: >From: "scott.marlowe" <scott.marlowe@ihs.com> >Subject: Re: [GENERAL] clarification of postgres limitations >To: mbc@soliton.com >cc: pgsql-general@postgresql.org >Date: Thu, 4 Mar 2004 10:49:49 -0700 (MST) >Message-ID: <Pine.LNX.4.33.0403041048240.11855-100000@css120.ihs.com> > >On Thu, 4 Mar 2004 mbc@soliton.com wrote: > >> Since it seems that the location of the server's data store is bound to a >> single directory, a database cannot span across multiple file systems. >> Further, does it imply that the maxiumum size of a database cannot exceed >> the maximum size of the underlying file system? > >With 7.5 you'll be able to easily put database structures on more than one >file system. > >As of 7.x series, the initlocation script allowed you to put individual >databases within a cluster on different storage points: > >http://www.postgresql.org/docs/7.4/static/manage-ag-alternate-locs.html -- "Nothing is either good or bad, but thinking makes it so." -- Shakespeare Myron B. Cheung Soliton Inc.