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Overview
Comment:Further enhancements to the in-memory shared-cache documentation.
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: bc46aa4246e75cb50ee9395b7f37d6a751548577
User & Date: drh 2012-05-28 17:30:48
Context
2012-05-28
17:52
Improvements to shared cache hyperlinking and fixes to the URI parameter documentation. check-in: 918202f13d user: drh tags: trunk
17:30
Further enhancements to the in-memory shared-cache documentation. check-in: bc46aa4246 user: drh tags: trunk
17:05
Documentation on the unicode61 tokenizer and the ability to use shared-cache with in-memory databases. check-in: 2ed85cc08c user: drh tags: trunk
Changes
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    hd_enable_main 1
  }
}

chng {date unknown (3.7.13)} {
<li>Add support for the [unicode61] tokenizer in [FTS3].
<li>[in-memory database | In-memory databases] that are specified using
    [URI filenames] are allowed to use [shared cache], so that the same

    in-memory database can be accessed from multiple database connections.
<li>Recognize and use the [coreqp | mode=memory] query parameter in
    [URI filenames].
}

chng {2012 May 22 (3.7.12.1)} {
<li>Fix a bug 







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    hd_enable_main 1
  }
}

chng {date unknown (3.7.13)} {
<li>Add support for the [unicode61] tokenizer in [FTS3].
<li>[in-memory database | In-memory databases] that are specified using
    [URI filenames] are allowed to use [in-memory shared-cache | shared cache],
    so that the same
    in-memory database can be accessed from multiple database connections.
<li>Recognize and use the [coreqp | mode=memory] query parameter in
    [URI filenames].
}

chng {2012 May 22 (3.7.12.1)} {
<li>Fix a bug 

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</td>
<td width="20"></td><td bgcolor="#044a64" width="1"></td><td width="20"></td>
<td valign="top">
<h3>Current Status</h3>

<p><ul>
<li><a href="releaselog/3_7_12_1.html">Version 3.7.12.1</a>
of SQLite is recommended for all new development.
Upgrading from version 3.7.6.3, 3.7.7, 3.7.7.1, 3.7.8, 3.7.9, 3.7.11,
or 3.7.12 is optional.
Upgrading from all other SQLite versions is recommended.</li>
</ul></p>

<h3>Common Links</h3>

<p><ul>
<li> <a href="features.html">Features</a> </li>







|


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</td>
<td width="20"></td><td bgcolor="#044a64" width="1"></td><td width="20"></td>
<td valign="top">
<h3>Current Status</h3>

<p><ul>
<li><a href="releaselog/3_7_13.html">Version 3.7.13</a>
of SQLite is recommended for all new development.
Upgrading from version 3.7.6.3, 3.7.7, 3.7.7.1, 3.7.8, 3.7.9, 3.7.11,
3.7.12, or 3.7.12.1 is optional.
Upgrading from all other SQLite versions is recommended.</li>
</ul></p>

<h3>Common Links</h3>

<p><ul>
<li> <a href="features.html">Features</a> </li>

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choose to participate or not participate in shared cache mode by using
the [SQLITE_OPEN_SHAREDCACHE] or [SQLITE_OPEN_PRIVATECACHE] flags the
third parameter.  The use of either of these flags overrides the
global shared cache mode setting established by [sqlite3_enable_shared_cache()].
No more than one of the flags should be used; if both SQLITE_OPEN_SHAREDCACHE
and SQLITE_OPEN_PRIVATECACHE flags are used in the third argument to
[sqlite3_open_v2()] then the behavior is undefined.</p>









































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choose to participate or not participate in shared cache mode by using
the [SQLITE_OPEN_SHAREDCACHE] or [SQLITE_OPEN_PRIVATECACHE] flags the
third parameter.  The use of either of these flags overrides the
global shared cache mode setting established by [sqlite3_enable_shared_cache()].
No more than one of the flags should be used; if both SQLITE_OPEN_SHAREDCACHE
and SQLITE_OPEN_PRIVATECACHE flags are used in the third argument to
[sqlite3_open_v2()] then the behavior is undefined.</p>

<p>When [URI filenames] are used, the "cache" query parameter can be used
to specify whether or not the database will use shared cache.  Use
"cache=shared" to enable shared cache and "cache=private" to disable
shared cache.   The ability to use URI query parameters to specify the
cache sharing behavior of a database connection allows cache sharing to
be controlled in [ATTACH] statements.  For example:</p>

<blockquote><pre>
ATTACH 'file:aux.db?cache=shared' AS aux;
</pre></blockquote>

<tcl>
hd_fragment inmemsharedcache {in-memory shared-cache}
HEADING 1 {Shared Cache And In-Memory Databases}</tcl>

<p>
Beginning with SQLite [version 3.7.13], shared cache can be used on
[in-memory databases], provided that the database is created using
a [URI filename].  For backwards compatibility, shared cache is always
disable for in-memory
databases if the unadorned name ":memory:" is used to open the database.
Prior to version 3.7.13, shared cache was always
disabled for in-memory databases regardless of the database name used,
current system shared cache setting, or query parameters or flags.
</p>

<p>
Enabling shared-cache for an in-mmeory database allows two or more
database connections in the same process to have access to the same
in-memory database.  An in-memory database in shared cache is automatically
deleted and memory is reclaimed when the last connection to that database
closes.
</p>

Changes to pages/uri.in.

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^The open attempt fails if <i>NAME</i> is not the name of a [VFS] that
is built into SQLite or that has been previously registered using
[sqlite3_vfs_register()].</dd>

<dt><b>mode=ro<br>mode=rw<br>mode=rwc<br>mode=memory</b></dt>
<dd><p>^The mode query parameter determines if the new database is opened
read-only, read-write, read-write and created if it does not exist, or
if the databaes is a pure in-memory database that never interacts with
disk, respectively.  The <b>mode=memory</b> option was added in 
[version 3.7.13].
</dd>

<dt><b>cache=shared<br>cache=private</b></dt>
<dd><p>^The cache query parameter determines if the new database is opened
using [shared cache mode] or with a private cache.







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^The open attempt fails if <i>NAME</i> is not the name of a [VFS] that
is built into SQLite or that has been previously registered using
[sqlite3_vfs_register()].</dd>

<dt><b>mode=ro<br>mode=rw<br>mode=rwc<br>mode=memory</b></dt>
<dd><p>^The mode query parameter determines if the new database is opened
read-only, read-write, read-write and created if it does not exist, or
that the database is a pure in-memory database that never interacts with
disk, respectively.  The <b>mode=memory</b> option was added in 
[version 3.7.13].
</dd>

<dt><b>cache=shared<br>cache=private</b></dt>
<dd><p>^The cache query parameter determines if the new database is opened
using [shared cache mode] or with a private cache.