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Yasuhiro KIMURA
578 lines
22 KiB
HTML
578 lines
22 KiB
HTML
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<title>Reviewing Berkeley DB log files</title>
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<link rel="stylesheet" href="gettingStarted.css" type="text/css" />
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<meta name="generator" content="DocBook XSL Stylesheets V1.73.2" />
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<link rel="start" href="index.html" title="Berkeley DB Installation and Build Guide" />
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<link rel="up" href="debug.html" title="Chapter 3. Debugging Applications" />
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<link rel="prev" href="debug_runtime.html" title="Run-time error information" />
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<link rel="next" href="build_win.html" title="Chapter 4. Building Berkeley DB for Windows" />
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</head>
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<body>
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<div xmlns="" class="navheader">
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<div class="libver">
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<p>Library Version 18.1.40</p>
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</div>
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<table width="100%" summary="Navigation header">
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<tr>
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<th colspan="3" align="center">Reviewing Berkeley DB log files</th>
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</tr>
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<tr>
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<td width="20%" align="left"><a accesskey="p" href="debug_runtime.html">Prev</a> </td>
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<th width="60%" align="center">Chapter 3. Debugging Applications </th>
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<td width="20%" align="right"> <a accesskey="n" href="build_win.html">Next</a></td>
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</tr>
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</table>
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<hr />
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</div>
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<div class="sect1" lang="en" xml:lang="en">
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<div class="titlepage">
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<div>
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<div>
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<h2 class="title" style="clear: both"><a id="debug_printlog"></a>Reviewing Berkeley DB log files</h2>
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</div>
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</div>
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</div>
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<div class="toc">
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<dl>
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<dt>
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<span class="sect2">
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<a href="debug_printlog.html#idm140649574887408">Augmenting the Log for Debugging</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="debug_printlog.html#idm140649575218160">Extracting Committed Transactions and Transaction Status</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="debug_printlog.html#idm140649575129712">Extracting Transaction Histories</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="debug_printlog.html#idm140649575143200">Extracting File Histories</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="debug_printlog.html#idm140649575012496">Extracting Page Histories</a>
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</span>
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</dt>
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<dt>
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<span class="sect2">
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<a href="debug_printlog.html#idm140649574800944">Other log processing tools</a>
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</span>
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</dt>
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</dl>
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</div>
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<p>
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If you are running with transactions and logging, the
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<a href="../api_reference/C/db_printlog.html" class="olink">db_printlog</a> utility can be a useful debugging aid. The <a href="../api_reference/C/db_printlog.html" class="olink">db_printlog</a> utility
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will display the contents of your log files in a human
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readable (and machine-readable) format.
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</p>
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<p>
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The <a href="../api_reference/C/db_printlog.html" class="olink">db_printlog</a> utility will attempt to display any and all log
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files present in a designated db_home directory. For each log
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record, the <a href="../api_reference/C/db_printlog.html" class="olink">db_printlog</a> utility will display a line of the form:
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</p>
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<pre class="programlisting">
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[22][28]db_big: rec: 43 txnid 80000963 prevlsn [21][10483281]</pre>
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<p>
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The opening numbers in square brackets are the
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<span class="emphasis"><em>log sequence number</em></span>
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(<span class="emphasis"><em>LSN</em></span>) of the log record being
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displayed. The first number indicates the log file in which
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the record appears, and the second number indicates the offset
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in that file of the record.
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</p>
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<p>
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The first character string identifies the particular log
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operation being reported. The log records corresponding to
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particular operations are described following. The rest of the
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line consists of name/value pairs.
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</p>
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<p>
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The rec field indicates the record type (this is used to
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dispatch records in the log to appropriate recovery
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functions).
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</p>
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<p>
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The txnid field identifies the transaction for which this
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record was written. A txnid of 0 means that the record was
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written outside the context of any transaction. You will see
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these most frequently for checkpoints.
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</p>
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<p>
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Finally, the prevlsn contains the LSN of the last record
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for this transaction. By following prevlsn fields, you can
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accumulate all the updates for a particular transaction.
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During normal abort processing, this field is used to quickly
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access all the records for a particular transaction.
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</p>
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<p>
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After the initial line identifying the record type, each
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field of the log record is displayed, one item per line. There
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are several fields that appear in many different records and a
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few fields that appear only in some records.
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</p>
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<p>
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The following table presents each currently written log
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record type with a brief description of the operation it
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describes. Any of these record types may have the string
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"_debug" appended if they were written because
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<a href="../api_reference/C/dbset_flags.html#dbset_flags_DB_TXN_NOT_DURABLE" class="olink">DB_TXN_NOT_DURABLE</a> was specified and the system was
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configured with <a class="link" href="build_unix_conf.html#build_unix_conf.--enable-diagnostic">--enable-diagnostic</a>.
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</p>
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<div class="informaltable">
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<table border="1" width="80%">
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<colgroup>
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<col />
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<col />
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</colgroup>
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<thead>
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<tr>
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<th>Log Record Type</th>
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<th>Description</th>
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</tr>
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</thead>
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<tbody>
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<tr>
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<td>bam_adj</td>
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<td>Used when we insert/remove an index
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into/from the page header of a Btree
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page.</td>
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</tr>
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<tr>
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<td>bam_cadjust</td>
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<td>Keeps track of record counts in a Btree or
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Recno database.</td>
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</tr>
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<tr>
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<td>bam_cdel</td>
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<td>Used to mark a record on a page as
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deleted.</td>
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</tr>
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<tr>
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<td>bam_curadj</td>
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<td>Used to adjust a cursor location when a
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nearby record changes in a Btree
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database.</td>
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</tr>
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<tr>
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<td>bam_merge</td>
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<td>Used to merge two Btree database pages
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during compaction.</td>
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</tr>
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<tr>
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<td>bam_pgno</td>
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<td>Used to replace a page number in a Btree
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record.</td>
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</tr>
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<tr>
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<td>bam_rcuradj</td>
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<td>Used to adjust a cursor location when a
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nearby record changes in a Recno
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database.</td>
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</tr>
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<tr>
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<td>bam_relink</td>
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<td>Fix leaf page prev/next chain when a page
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is removed.</td>
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</tr>
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<tr>
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<td>bam_repl</td>
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<td>Describes a replace operation on a
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record.</td>
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</tr>
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<tr>
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<td>bam_root</td>
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<td>Describes an assignment of a root
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page.</td>
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</tr>
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<tr>
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<td>bam_rsplit</td>
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<td>Describes a reverse page split.</td>
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</tr>
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<tr>
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<td>bam_split</td>
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<td>Describes a page split.</td>
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</tr>
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<tr>
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<td>crdel_inmem_create</td>
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<td>Record the creation of an in-memory named
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database.</td>
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</tr>
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<tr>
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<td>crdel_inmem_remove</td>
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<td>Record the removal of an in-memory named
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database.</td>
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</tr>
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<tr>
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<td>crdel_inmem_rename</td>
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<td>Record the rename of an in-memory named
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database.</td>
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</tr>
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<tr>
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<td>crdel_metasub</td>
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<td>Describes the creation of a metadata page
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for a subdatabase.</td>
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</tr>
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<tr>
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<td>db_addrem</td>
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<td>Add or remove an item from a page of
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duplicates.</td>
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</tr>
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<tr>
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<td>db_big</td>
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<td>Add an item to an overflow page
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(<span class="emphasis"><em>overflow pages</em></span>
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contain items too large to place on the main
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page)</td>
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</tr>
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<tr>
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<td>db_cksum</td>
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<td>Unable to checksum a page.</td>
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</tr>
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<tr>
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<td>db_debug</td>
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<td>Log debugging message.</td>
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</tr>
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<tr>
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<td>db_noop</td>
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<td>This marks an operation that did nothing
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but update the LSN on a page.</td>
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</tr>
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<tr>
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<td>db_ovref</td>
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<td>Increment or decrement the reference count
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for a big item.</td>
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</tr>
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<tr>
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<td>db_pg_alloc</td>
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<td>Indicates we allocated a page to a
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database.</td>
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</tr>
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<tr>
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<td>db_pg_free</td>
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<td>Indicates we freed a page (freed pages are
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added to a freelist and reused).</td>
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</tr>
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<tr>
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<td>db_pg_freedata</td>
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<td>Indicates we freed a page that still
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contained data entries (freed pages are added
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to a freelist and reused.)</td>
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</tr>
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<tr>
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<td>db_pg_init</td>
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<td>Indicates we reinitialized a page during a
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truncate.</td>
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</tr>
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<tr>
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<td>db_pg_sort</td>
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<td>Sort the free page list and free pages at
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the end of the file.</td>
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</tr>
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<tr>
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<td>dbreg_register</td>
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<td>Records an open of a file (mapping the
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filename to a log-id that is used in
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subsequent log operations).</td>
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</tr>
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<tr>
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<td>fop_create</td>
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<td>Create a file in the file system.</td>
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</tr>
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<tr>
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<td>fop_file_remove</td>
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<td>Remove a name in the file system.</td>
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</tr>
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<tr>
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<td>fop_remove</td>
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<td>Remove a file in the file system.</td>
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</tr>
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<tr>
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<td>fop_rename</td>
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<td>Rename a file in the file system.</td>
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</tr>
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<tr>
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<td>fop_write</td>
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<td>Write bytes to an object in the file
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system.</td>
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</tr>
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<tr>
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<td>ham_chgpg</td>
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<td>Used to adjust a cursor location when a
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Hash page is removed, and its elements are
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moved to a different Hash page.</td>
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</tr>
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<tr>
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<td>ham_copypage</td>
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<td>Used when we empty a bucket page, but there
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are overflow pages for the bucket; one needs
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to be copied back into the actual
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bucket.</td>
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</tr>
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<tr>
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<td>ham_curadj</td>
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<td>Used to adjust a cursor location when a
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nearby record changes in a Hash
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database.</td>
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</tr>
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<tr>
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<td>ham_groupalloc</td>
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<td>Allocate some number of contiguous pages to
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the Hash database.</td>
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</tr>
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<tr>
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<td>ham_insdel</td>
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<td>Insert/delete an item on a Hash
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page.</td>
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</tr>
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<tr>
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<td>ham_metagroup</td>
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<td>Update the metadata page to reflect the
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allocation of a sequence of contiguous
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pages.</td>
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</tr>
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<tr>
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<td>ham_newpage</td>
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<td>Adds or removes overflow pages from a Hash
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bucket.</td>
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</tr>
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<tr>
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<td>ham_replace</td>
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<td>Handle updates to records that are on the
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main page.</td>
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</tr>
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<tr>
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<td>ham_splitdata</td>
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<td>Record the page data for a split.</td>
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</tr>
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<tr>
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<td>heap_addrem</td>
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<td>Add or remove an entry from a Heap
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database.</td>
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</tr>
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<tr>
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<td>heap_pg_alloc</td>
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<td>Indicates we allocated a page to a Heap
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database.</td>
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</tr>
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<tr>
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<td>heap_trunc_meta</td>
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<td>Records the truncation of the meta page in
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a Heap database.</td>
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</tr>
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||
<tr>
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<td>heap_trunc_page</td>
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<td>Records the truncation of a data page in a
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Heap database.</td>
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</tr>
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||
<tr>
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||
<td>qam_add</td>
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<td>Describes the actual addition of a new
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record to a Queue.</td>
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</tr>
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||
<tr>
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||
<td>qam_del</td>
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<td>Delete a record in a Queue.</td>
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</tr>
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||
<tr>
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||
<td>qam_delext</td>
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||
<td>Delete a record in a Queue with
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||
extents.</td>
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||
</tr>
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||
<tr>
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||
<td>qam_incfirst</td>
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||
<td>Increments the record number that refers to
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||
the first record in the database.</td>
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||
</tr>
|
||
<tr>
|
||
<td>qam_mvptr</td>
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||
<td>Indicates we changed the reference to
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||
either or both of the first and current
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||
records in the file.</td>
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||
</tr>
|
||
<tr>
|
||
<td>txn_child</td>
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||
<td>Commit a child transaction.</td>
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||
</tr>
|
||
<tr>
|
||
<td>txn_ckp</td>
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||
<td>Transaction checkpoint.</td>
|
||
</tr>
|
||
<tr>
|
||
<td>txn_recycle</td>
|
||
<td>Transaction IDs wrapped.</td>
|
||
</tr>
|
||
<tr>
|
||
<td>txn_regop</td>
|
||
<td>Logs a regular (non-child) transaction
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||
commit.</td>
|
||
</tr>
|
||
<tr>
|
||
<td>txn_xa_regop</td>
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||
<td>Logs a prepare message.</td>
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||
</tr>
|
||
</tbody>
|
||
</table>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm140649574887408"></a>Augmenting the Log for Debugging</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
When debugging applications, it is sometimes useful to
|
||
log not only the actual operations that modify pages, but
|
||
also the underlying Berkeley DB functions being executed.
|
||
This form of logging can add significant bulk to your log,
|
||
but can permit debugging application errors that are
|
||
almost impossible to find any other way. To turn on these
|
||
log messages, specify the --enable-debug_rop and
|
||
--enable-debug_wop configuration options when configuring
|
||
Berkeley DB. See <a class="xref" href="build_unix_conf.html" title="Configuring Berkeley DB">Configuring Berkeley DB</a> for more
|
||
information.
|
||
</p>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm140649575218160"></a>Extracting Committed Transactions and Transaction Status</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
Sometimes, it is helpful to use the human-readable log
|
||
output to determine which transactions committed and
|
||
aborted. The awk script, commit.awk, (found in the
|
||
db_printlog directory of the Berkeley DB distribution)
|
||
allows you to do just that. The following command, where
|
||
log_output is the output of db_printlog, will display a
|
||
list of the transaction IDs of all committed transactions
|
||
found in the log:
|
||
</p>
|
||
<pre class="programlisting">awk -f commit.awk log_output</pre>
|
||
<p>
|
||
If you need a complete list of both committed and
|
||
aborted transactions, then the script status.awk will
|
||
produce it. The syntax is as follows: </p>
|
||
<pre class="programlisting">awk -f status.awk log_output</pre>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm140649575129712"></a>Extracting Transaction Histories</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
Another useful debugging aid is to print out the
|
||
complete history of a transaction. The awk script txn.awk
|
||
allows you to do that. The following command line, where
|
||
log_output is the output of the <a href="../api_reference/C/db_printlog.html" class="olink">db_printlog</a> utility and txnlist
|
||
is a comma-separated list of transaction IDs, will display
|
||
all log records associated with the designated transaction
|
||
ids:
|
||
</p>
|
||
<pre class="programlisting">awk -f txn.awk TXN=txnlist log_output</pre>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm140649575143200"></a>Extracting File Histories</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The awk script fileid.awk allows you to extract all log
|
||
records that refer to a designated file. The syntax for
|
||
the fileid.awk script is the following, where log_output
|
||
is the output of db_printlog and fids is a comma-separated
|
||
list of fileids:
|
||
</p>
|
||
<pre class="programlisting">awk -f fileid.awk PGNO=fids log_output</pre>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm140649575012496"></a>Extracting Page Histories</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The awk script pgno.awk allows you to extract all log
|
||
records that refer to designated page numbers. However,
|
||
because this script will extract records with the
|
||
designated page numbers for all files, it is most useful
|
||
in conjunction with the fileid script. The syntax for the
|
||
pgno.awk script is the following, where log_output is the
|
||
output of db_printlog and pgnolist is a comma-separated
|
||
list of page numbers:
|
||
</p>
|
||
<pre class="programlisting">awk -f pgno.awk PGNO=pgnolist log_output</pre>
|
||
</div>
|
||
<div class="sect2" lang="en" xml:lang="en">
|
||
<div class="titlepage">
|
||
<div>
|
||
<div>
|
||
<h3 class="title"><a id="idm140649574800944"></a>Other log processing tools</h3>
|
||
</div>
|
||
</div>
|
||
</div>
|
||
<p>
|
||
The awk script count.awk prints out the number of log
|
||
records encountered that belonged to some transaction
|
||
(that is, the number of log records excluding those for
|
||
checkpoints and non-transaction-protected operations).
|
||
</p>
|
||
<p>
|
||
The script range.awk will extract a subset of a log.
|
||
This is useful when the output of <a href="../api_reference/C/db_printlog.html" class="olink">db_printlog</a> utility is too
|
||
large to be reasonably manipulated with an editor or other
|
||
tool. The syntax for range.awk is the following, where
|
||
<span class="bold"><strong>sf</strong></span> and <span class="bold"><strong>so</strong></span> represent the LSN of the
|
||
beginning of the sublog you want to extract, and <span class="bold"><strong>ef</strong></span> and <span class="bold"><strong>eo</strong></span>
|
||
represent the LSN of the end of the
|
||
sublog you want to extract:
|
||
</p>
|
||
<pre class="programlisting"> awk -f range.awk START_FILE=sf START_OFFSET=so END_FILE=ef \
|
||
END_OFFSET=eo log_output </pre>
|
||
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|
||
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