Thread

1. glossary Data page

   The Post Office <noreply@postgresql.org> — 2026-06-29T05:49:11Z

   The following documentation comment has been logged on the website:
   
   Page: https://www.postgresql.org/docs/18/glossary.html
   Description:
   
   > The basic structure used to store relation data. All pages are of the same
   size. Data pages are typically stored on disk, each in a specific file, and
   can be read to shared buffers where they can be modified, becoming dirty.
   They become clean when written to disk. New pages, which initially exist in
   memory only, are also dirty until written.
   
   Am I correct in understanding from this description that all files on the
   disk will be the same size?
   One page = one file?
   
   
   
   
   

2. Re: glossary Data page

   David G. Johnston <david.g.johnston@gmail.com> — 2026-06-30T13:28:39Z

   On Sunday, June 28, 2026, PG Doc comments form <noreply@postgresql.org>
   wrote:
   
   > The following documentation comment has been logged on the website:
   >
   > Page: https://www.postgresql.org/docs/18/glossary.html
   > Description:
   >
   > > The basic structure used to store relation data. All pages are of the
   > same
   > size. Data pages are typically stored on disk, each in a specific file, and
   > can be read to shared buffers where they can be modified, becoming dirty.
   > They become clean when written to disk. New pages, which initially exist in
   > memory only, are also dirty until written.
   >
   > Am I correct in understanding from this description that all files on the
   > disk will be the same size?
   > One page = one file?
   >
   
   No.  A page is an atomic unit subset of a file.  Files contain many pages.
   It would be crazy to limit file sizes to 8kb when we have GB available.
   
   David J.
   

3. Re: glossary Data page

   Yaroslav Saburov <y.saburov@gmail.com> — 2026-06-30T15:04:53Z

   Maybe these are just the intricacies of translation.
   This is how I interpret it:
   
   1) All pages are the same size.
   2) Data pages are usually stored on disk,
   3) each in a separate file, 
   
   > 1) All pages are of the same size.
   > 2) Data pages are typically stored on disk
   > 3) each in a specific file,
   
   > 30 черв. 2026 р. о 16:28 David G. Johnston <david.g.johnston@gmail.com> пише:
   > 
   > On Sunday, June 28, 2026, PG Doc comments form <noreply@postgresql.org> wrote:
   >> The following documentation comment has been logged on the website:
   >> 
   >> Page: https://www.postgresql.org/docs/18/glossary.html
   >> Description:
   >> 
   >> > The basic structure used to store relation data. All pages are of the same
   >> size. Data pages are typically stored on disk, each in a specific file, and
   >> can be read to shared buffers where they can be modified, becoming dirty.
   >> They become clean when written to disk. New pages, which initially exist in
   >> memory only, are also dirty until written.
   >> 
   >> Am I correct in understanding from this description that all files on the
   >> disk will be the same size?
   >> One page = one file?
   > 
   > No.  A page is an atomic unit subset of a file.  Files contain many pages.  It would be crazy to limit file sizes to 8kb when we have GB available.
   > 
   > David J. 
   

4. Re: glossary Data page

   David G. Johnston <david.g.johnston@gmail.com> — 2026-06-30T16:51:30Z

   On Tue, Jun 30, 2026 at 8:04 AM Yaroslav Saburov <y.saburov@gmail.com>
   wrote:
   
   > Maybe these are just the intricacies of translation.
   >
   > This is how I interpret it:
   >
   >
   > 1) All pages are the same size.
   >
   > 2) Data pages are usually stored on disk,
   >
   > 3) each in a separate file,
   >
   >
   > > 1) All pages are of the same size.
   >
   > > 2) Data pages are typically stored on disk
   >
   > > 3) each in a specific file,
   >
   
   More that the author is being imprecise here so as not to overwhelm
   the reader with detail.
   
   Patches are welcome, though at present I have no intent to write one.
   
   David J.