Documentation Source Text

proc DebugDisclaimer {} {
  return {
    <p style='background-color: #f0e0ff;'>
    This pragma is intended for use when debugging SQLite itself.  It
    is only contained in the build when the [SQLITE_DEBUG] compile-time option
    is used.</p>
  }
}
proc TestDisclaimer {} {
  return {
    <p style='background-color: #f0e0ff;'>
    The intended use of this pragma is only for testing and validation of
    SQLite.  This pragma is subject to change without notice and is not
    recommended for use by application programs.</p>
  }
}
# Legacy pragma - do not use these
proc LegacyPragma {namelist content} {
  Pragma $namelist [string map [list DISCLAIMER [LegacyDisclaimer]] $content]
  global PragmaLegacy
  foreach x $namelist {set PragmaLegacy($x) 1}
}
# Debugging pragmas
proc DebugPragma {namelist content} {
  Pragma $namelist [string map [list DISCLAIMER [DebugDisclaimer]] $content]
  global PragmaDebug
  foreach x $namelist {set PragmaDebug($x) 1}
}
# Testing pragmas
proc TestPragma {namelist content} {
  Pragma $namelist [string map [list DISCLAIMER [TestDisclaimer]] $content]
  global PragmaTest
  foreach x $namelist {set PragmaTest($x) 1}
}

</tcl>

<p>The PRAGMA statement is an SQL extension specific to SQLite and used to 
modify the operation of the SQLite library or to query the SQLite library for 
internal (non-table) data. The PRAGMA statement is issued using the same
interface as other SQLite commands (e.g. [SELECT], [INSERT]) but is

    <p>This pragma returns one row for each index associated with the
    given table.)^
    ^Columns of the result set include the
    index name and a flag to indicate whether or not the index is UNIQUE.
    </p>
}

TestPragma stats {
    <p>^(<b>PRAGMA stats;</b>)^ </p>
    <p>This pragma returns auxiliary information about tables and
    indices.  The returned information is used during testing to help
    verify that the query planner is operating correctly.  The format
    and meaning of this pragma will likely change from release
    to the next. Because of its volatility, the behavior and output
    format of this pragma are deliberately undocumented.</p>

    DISCLAIMER
}

Pragma page_count {
    <p>^(<b>PRAGMA page_count;</b></p>
    <p>Return the total number of pages in the database file.</p>)^
}

for {set i 0} {$i<$nprag} {incr i} {
  set prag [lindex $allprag $i]
  set ref $PragmaRef($prag)
  if {[info exists PragmaLegacy($prag)]} {
    hd_puts "<li><a href=\"#pragma_$ref\"><s>$prag</s></a>&sup1;\n"
  } elseif {[info exists PragmaDebug($prag)]} {
    hd_puts "<li><a href=\"#pragma_$ref\"><i>$prag</i></a>&sup2;\n"
  } elseif {[info exists PragmaTest($prag)]} {
    hd_puts "<li><a href=\"#pragma_$ref\"><i>$prag</i></a>&sup3;\n"
  } else {
    hd_puts "<li><a href=\"#pragma_$ref\">$prag</a>\n"
  }
  if {$i%$nrow==($nrow-1) && $i+1<$nprag} {
    hd_puts "</ul></td><td valign=\"top\" align=\"left\"><ul>\n"
  }
}
</tcl>
</ul></td></tr></table>
<p>Notes:
<ol>
<li>Pragmas whose names are marked through in the list above
are deprecated that are maintained for historical compatibility only.
Do not use the deprecated pragmas in new applications.
Remove deprecated pragmas
from existing applications at your earliest opportunity.</blockquote>
<li>These pragmas are used for debugging SQLite and
are only available when SQLite is compiled using [SQLITE_DEBUG].
<li>These pragmas are used for testing SQLite and are not recommended
for use in application programs.</ol></p>
<tcl>
foreach prag [lsort [array names PragmaBody]] {
  hd_fragment pragma_$prag
  foreach x $PragmaKeys($prag) {
    hd_keywords *$x "PRAGMA $x" "$x pragma"
  }
  hd_puts "<hr>"
  hd_resolve $PragmaBody($prag)
}
</tcl>
<hr>

<title>SQLite Database Speed Comparison</title>

<h2>Database Speed Comparison</h2>

<font color="red"><b>
Note:  This document is very very old.  It describes a speed comparison between
archaic versions of SQLite, MySQL and PostgreSQL.  
<p>
The numbers here have become meaningless.  This page has been retained only

as an historical artifact.  
</b></font>

<h3>Executive Summary</h3>

<p>A series of tests were run to measure the relative performance of
SQLite 2.7.6, PostgreSQL 7.1.3, and MySQL 3.23.41.
The following are general