diff --git a/doc/src/sgml/file-fdw.sgml b/doc/src/sgml/file-fdw.sgml index dd712e92636f207e989486e0d3fca6e9b9618625..900b0553f7826f425c08fa9decc63c2fafbb4fe9 100644 --- a/doc/src/sgml/file-fdw.sgml +++ b/doc/src/sgml/file-fdw.sgml @@ -158,4 +158,76 @@ specified, the file size (in bytes) is shown as well. </para> + <example> + <title id="csvlog-fdw">Create a Foreign Table for PostgreSQL CSV Logs</title> + + <para> + One of the obvious uses for the <literal>file_fdw</> is to make + the PostgreSQL activity log available as a table for querying. To + do this, first you must be logging to a CSV file, which here we + will call <literal>pglog.csv</>. First, install <literal>file_fdw</> + as an extension: + </para> + +<programlisting> +CREATE EXTENSION file_fdw; +</programlisting> + + <para> + Next, create the foreign data wrapper: + +<programlisting> +CREATE FOREIGN DATA WRAPPER file_fdw HANDLER file_fdw_handler; +</programlisting> + </para> + + <para> + Then create a foreign data server: + +<programlisting> +CREATE SERVER pglog FOREIGN DATA WRAPPER file_fdw; +</programlisting> + </para> + + <para> + Now you are ready to create the foreign data table. Using the + <command>CREATE FOREIGN TABLE</> command, you will need to define + the columns for the table, the CSV filename, and its format: + +<programlisting> +CREATE FOREIGN TABLE pglog ( + log_time timestamp(3) with time zone, + user_name text, + database_name text, + process_id integer, + connection_from text, + session_id text, + session_line_num bigint, + command_tag text, + session_start_time timestamp with time zone, + virtual_transaction_id text, + transaction_id bigint, + error_severity text, + sql_state_code text, + message text, + detail text, + hint text, + internal_query text, + internal_query_pos integer, + context text, + query text, + query_pos integer, + location text, + application_name text +) SERVER pglog +OPTIONS ( filename '/home/josh/9.1/data/pg_log/pglog.csv', format 'csv' ); +</programlisting> + </para> + + <para> + That's it — now you can query your log directly. In production, of course, + you would need to define some way to adjust to log rotation. + </para> + </example> + </sect1>