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><H1
><A
NAME="PGXLOGDUMP"
></A
><SPAN
CLASS="APPLICATION"
>pg_xlogdump</SPAN
></H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN159063"
></A
><H2
>Name</H2
>pg_xlogdump -- Display a human-readable rendering of the write-ahead log of a <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> database cluster</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN159069"
></A
><H2
>Synopsis</H2
><P
><TT
CLASS="COMMAND"
>pg_xlogdump</TT
> [<TT
CLASS="OPTION"
>option</TT
>...] [<TT
CLASS="OPTION"
>startseg</TT
>
[<TT
CLASS="OPTION"
>endseg</TT
>]
]</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="R1-APP-PGXLOGDUMP-1"
></A
><H2
>Description</H2
><P
> <TT
CLASS="COMMAND"
>pg_xlogdump</TT
> displays the write-ahead log (WAL) and is mainly
useful for debugging or educational purposes.
</P
><P
> This utility can only be run by the user who installed the server, because
it requires read-only access to the data directory.
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN159083"
></A
><H2
>Options</H2
><P
> The following command-line options control the location and format of the
output:
<P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><TT
CLASS="REPLACEABLE"
><I
>startseg</I
></TT
></DT
><DD
><P
> Start reading at the specified log segment file. This implicitly determines
the path in which files will be searched for, and the timeline to use.
</P
></DD
><DT
><TT
CLASS="REPLACEABLE"
><I
>endseg</I
></TT
></DT
><DD
><P
> Stop after reading the specified log segment file.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-b</TT
><BR><TT
CLASS="OPTION"
>--bkp-details</TT
></DT
><DD
><P
> Output detailed information about backup blocks.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-e <TT
CLASS="REPLACEABLE"
><I
>end</I
></TT
></TT
><BR><TT
CLASS="OPTION"
>--end=<TT
CLASS="REPLACEABLE"
><I
>end</I
></TT
></TT
></DT
><DD
><P
> Stop reading at the specified log position, instead of reading to the
end of the log stream.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-n <TT
CLASS="REPLACEABLE"
><I
>limit</I
></TT
></TT
><BR><TT
CLASS="OPTION"
>--limit=<TT
CLASS="REPLACEABLE"
><I
>limit</I
></TT
></TT
></DT
><DD
><P
> Display the specified number of records, then stop.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-p <TT
CLASS="REPLACEABLE"
><I
>path</I
></TT
></TT
><BR><TT
CLASS="OPTION"
>--path=<TT
CLASS="REPLACEABLE"
><I
>path</I
></TT
></TT
></DT
><DD
><P
> Directory in which to find log segment files. The default is to search
for them in the <TT
CLASS="LITERAL"
>pg_xlog</TT
> subdirectory of the current
directory.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-r <TT
CLASS="REPLACEABLE"
><I
>rmgr</I
></TT
></TT
><BR><TT
CLASS="OPTION"
>--rmgr=<TT
CLASS="REPLACEABLE"
><I
>rmgr</I
></TT
></TT
></DT
><DD
><P
> Only display records generated by the specified resource manager.
If <TT
CLASS="LITERAL"
>list</TT
> is passed as name, print a list of valid resource manager
names, and exit.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-s <TT
CLASS="REPLACEABLE"
><I
>start</I
></TT
></TT
><BR><TT
CLASS="OPTION"
>--start=<TT
CLASS="REPLACEABLE"
><I
>start</I
></TT
></TT
></DT
><DD
><P
> Log position at which to start reading. The default is to start reading
the first valid log record found in the earliest file found.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-t <TT
CLASS="REPLACEABLE"
><I
>timeline</I
></TT
></TT
><BR><TT
CLASS="OPTION"
>--timelime=<TT
CLASS="REPLACEABLE"
><I
>timeline</I
></TT
></TT
></DT
><DD
><P
> Timeline from which to read log records. The default is to use the
value in <TT
CLASS="LITERAL"
>startseg</TT
>, if that is specified; otherwise, the
default is 1.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-V</TT
><BR><TT
CLASS="OPTION"
>--version</TT
></DT
><DD
><P
> Print the <SPAN
CLASS="APPLICATION"
>pg_xlogdump</SPAN
> version and exit.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-x <TT
CLASS="REPLACEABLE"
><I
>xid</I
></TT
></TT
><BR><TT
CLASS="OPTION"
>--xid=<TT
CLASS="REPLACEABLE"
><I
>xid</I
></TT
></TT
></DT
><DD
><P
> Only display records marked with the given TransactionId.
</P
></DD
><DT
><TT
CLASS="OPTION"
>-?</TT
><BR><TT
CLASS="OPTION"
>--help</TT
></DT
><DD
><P
> Show help about <SPAN
CLASS="APPLICATION"
>pg_xlogdump</SPAN
> command line
arguments, and exit.
</P
></DD
></DL
></DIV
><P>
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN159186"
></A
><H2
>Notes</H2
><P
> Can give wrong results when the server is running.
</P
><P
> Only the specified timeline is displayed (or the default, if none is
specified). Records in other timelines are ignored.
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN159190"
></A
><H2
>See Also</H2
><A
HREF="wal-internals.html"
>Section 29.5</A
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