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Comment:Update the whentouse.html document to mention that less bitmap memory is used for larger page sizes. (CVS 3843)
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SHA1: 2c8e2a5be34cdfe11ef22bd6f78ec0519f497392
User & Date: drh 2007-04-14 12:04:39.000
Context
2007-04-16
15:02
Detect database file changes using a 128-bit segment of the file header that includes the change counter. Ticket #2303. (CVS 3844) (check-in: e44995debf user: drh tags: trunk)
2007-04-14
12:04
Update the whentouse.html document to mention that less bitmap memory is used for larger page sizes. (CVS 3843) (check-in: 2c8e2a5be3 user: drh tags: trunk)
2007-04-13
16:06
Match ORDER BY terms to columns using names in compound queries. Make sure this works for subqueries, especially in the right-hand side of an IN operator. Ticket #2296. (CVS 3842) (check-in: cfc6f933dc user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to www/whentouse.tcl. 
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#
# Run this TCL script to generate HTML for the goals.html file.
#
set rcsid {$Id: whentouse.tcl,v 1.6 2005/08/16 14:44:49 drh Exp $}
source common.tcl
header {Appropriate Uses For SQLite}

puts {
<p>
SQLite is different from most other SQL database engines in that its
primary design goal is to be simple:




|








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#
# Run this TCL script to generate HTML for the goals.html file.
#
set rcsid {$Id: whentouse.tcl,v 1.7 2007/04/14 12:04:39 drh Exp $}
source common.tcl
header {Appropriate Uses For SQLite}

puts {
<p>
SQLite is different from most other SQL database engines in that its
primary design goal is to be simple:
︙︙
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<li><p><b>Very large datasets</b></p>

<p>When you start a transaction in SQLite (which happens automatically
before any write operation that is not within an explicit BEGIN...COMMIT)
the engine has to allocate a bitmap of dirty pages in the disk file to
help it manage its rollback journal.  SQLite needs 256 bytes of RAM for


every 1MB of database.  For smaller databases, the amount of memory
required is not a problem, but when database begin to grow into the
multi-gigabyte range, the size of the bitmap can get quite large.  If
you need to store and modify more than a few dozen GB of data, you should
consider using a different database engine.
</p>
</li>









>
>
|








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<li><p><b>Very large datasets</b></p>

<p>When you start a transaction in SQLite (which happens automatically
before any write operation that is not within an explicit BEGIN...COMMIT)
the engine has to allocate a bitmap of dirty pages in the disk file to
help it manage its rollback journal.  SQLite needs 256 bytes of RAM for
every 1MiB of database (assuming a 1024-byte page size: less memory is
used with larger page sizes, of course).  
For smaller databases, the amount of memory
required is not a problem, but when database begin to grow into the
multi-gigabyte range, the size of the bitmap can get quite large.  If
you need to store and modify more than a few dozen GB of data, you should
consider using a different database engine.
</p>
</li>
︙︙