9 CTX_OUTPUT Package

This chapter provides reference information for using the CTX_OUTPUT PL/SQL package.

CTX_OUTPUT contains the following stored procedures:

Name	Description
ADD_EVENT	Adds an event to the index log.
ADD_TRACE	Enables tracing.
DISABLE_QUERY_STATS	Turns off the gathering of query stats for the index.
ENABLE_QUERY_STATS	Enables gathering of query stats for the index.
END_LOG	Halts logging of index and document services requests.
END_QUERY_LOG	Stops logging queries into a logfile.
GET_TRACE_VALUE	Returns the value of a trace.
LOG_TRACES	Prints traces to logfile.
LOGFILENAME	Returns the name of the current log file.
REMOVE_EVENT	Removes an event from the index log.
REMOVE_TRACE	Disables tracing.
RESET_TRACE	Clears a trace.
START_LOG	Starts logging index and document service requests.
START_QUERY_LOG	Creates a log file of queries.

ADD_EVENT

Use this procedure to add an event to the index log for more detailed log output.

Syntax

CTX_OUTPUT.ADD_EVENT(event in NUMBER);

event

Specify the type of index event to log. You can add the following events:

CTX_OUTPUT.EVENT_INDEX_PRINT_ROWID, which logs the rowid of each row after it is indexed. This is useful for debugging a failed index operation.
CTX_OUTPUT.EVENT_OPT_PRINT_TOKEN, which prints each token as it is being optimized.
CTX_OUTPUT.EVENT_INDEX_PRINT_TOKEN, which prints the each token as it is being indexed.

Example

begin
CTX_OUTPUT.ADD_EVENT(CTX_OUTPUT.EVENT_INDEX_PRINT_ROWID);
end;

Related Topics

See Also:

REMOVE_EVENT

ADD_TRACE

Use this procedure to enable a trace. If the trace has not been enabled, this call adds the trace to the list of active traces and resets its value to 0. If the trace has already been enabled, an error is raised.

Syntax

CTX_OUTPUT.ADD_TRACE(trace_id BINARY_INTEGER);

trace_id: Specify the ID of the trace to enable. See Table 9-1 for possible trace values.

Notes

Table 9-1 shows the available traces:

Table 9-1 Available Traces

Symbol	ID	Metric
`TRACE_IDX_USER_DATASTORE`	1	Time spent executing user datastore
`TRACE_IDX_AUTO_FILTER`	2	Time spent invoking the `AUTO_FILTER` filter. (Replaces the deprecated `TRACE_IDX_INSO_FILTER` trace)
`TRACE_QRY_XX_TIME`	3	Time spent executing the `$X` cursor
`TRACE_QRY_XF_TIME`	4	Time spent fetching from `$X`
`TRACE_QRY_X_ROWS`	5	Total number of rows whose token metadata was fetched from `$X`
`TRACE_QRY_IF_TIME`	6	Time spent fetching the `LOB` locator from `$I`
`TRACE_QRY_IR_TIME`	7	Time spent reading `$I` `LOB` information
`TRACE_QRY_I_ROWS`	8	Number of rows whose `$I` `token_info` was actually read
`TRACE_QRY_I_SIZE`	9	Number of bytes read from `$I` `LOB`s
`TRACE_QRY_R_TIME`	10	Time spent fetching and reading `$R` information
`TRACE_QRY_CON_TIME`	11	Time spent in `CONTAINS` processing (`drexrcontains/drexrstart/drexrfetch)`
TRACE_QRY_S_TIME	15	Time spent fetching and reading `$S` information

Tracing is independent of logging. Logging does not have to be on to start tracing, and vice-versa.

Traces are associated with a session—they can measure operations that take place within a single session, and conversely, cannot make measurements across sessions.

During parallel sync or optimize, the trace profile will be copied to the slave sessions if and only if tracing is currently enabled. Each slave will accumulate its own traces and implicitly write all trace values to the slave logfile before termination.

Related Topics

DISABLE_QUERY_STATS

Disables gathering of query stats for the index.

Syntax

ctx_output.disable_query_stats(
index_name IN VARCHAR2
);

index_name: The name of the index on which query stats collection is to be disabled.

Example

Turn off gathering of query stats for the index myindex.

CTX_OUTPUT.DISABLE_QUERY_STATS(myindex);

Notes

Once the query stats is disabled for an index, gathering and storing query-related metadata is stopped for that index. All the entries corresponding to that index are cleared from the dictionary tables. An error is returned if you call this procedure on an index where query stats is not enabled.

Related Topics

CTX_OUTPUT.ENABLE_QUERY_STATS, and CTX_REPORT.INDEX_STATS.

ENABLE_QUERY_STATS

Enables gathering of query stats for the index. To have query-related metadata stored for the index, use this procedure to enable collection of statistics on that index. You can only access the gathered metadata when query stats is enabled.

Note:

Accessing the query stats metadata only works when ctx_outout.enable_query_stats is turned on for the index. Please see CTX_REPORT.INDEX_STATS for the list of gathered query stats metadata.

Syntax

ctx_outout.enable_query_stats(
index_name IN VARCHAR2
);

index_name: The name of the index on which query stats collection is to be enabled.

Example

Turn on gathering of query stats for the index myindex.

CTX_OUTOUT.ENABLE_QUERY_STATS(myindex);

Notes

The information that shows whether query stats is enabled on an index is available in the views: CTX_INDEXES and CTX_USER_INDEXES under the column idx_query_stats_enabled, which is in both of these views. If query_stats is enabled for an index, the column displays YES; if not, the column displays NO.

The data corresponding to the query statistics will be stored in persistent dictionary tables. Once statistics has been enabled for a particular index, query statistics will be collected for that index from all sessions.

If you call this procedure for an index where query stats is already enabled, an error will be thrown.

Statistics collection has a minimal affect on query performance.

Related Topics

CTX_OUTPUT.DISABLE_QUERY_STATS, and CTX_REPORT.INDEX_STATS.

END_LOG

This procedure halts logging index and document service requests.

Syntax

ctx_output.end_log;

Example

begin
CTX_OUTPUT.END_LOG;
end;

END_QUERY_LOG

Use this procedure to stop logging queries into a logfile created with CTX_OUTPUT.START_QUERY_LOG.

Syntax

ctx_output.end_query_log;

Example

begin

CTX_OUTPUT.START_QUERY_LOG('mylog1');
     < get queries >
CTX_OUTPUT.END_QUERY_LOG;

end;

GET_TRACE_VALUE

Use this procedure to programmatically retrieve the current value of a trace.

Syntax

CTX_OUTPUT.GET_TRACE_VALUE(trace_id BINARY_INTEGER);

trace_id: Specify the trace ID whose value you want. See Table 9-1, "Available Traces" for possible values.

Example

This sets the value of the variable value:

value := ctx_output.get_trace_value(trace_id);

Notes

You can also retrieve trace values through SQL:

select * from ctx_trace_values;

See "CTX_TRACE_VALUES" for the entries in the CTX_TRACE_VALUES view.

If the trace has not been enabled, an error is raised.

Traces are not reset to 0 by this call.

Traces are associated with a session—they can measure operations that take place within a single session, and conversely, cannot make measurements across sessions.

Related Topics

LOG_TRACES

Use this procedure to print all active traces to the logfile.

Syntax

CTX_OUTPUT.LOG_TRACES;

Notes

If logging has not been started, an error is raised.

Traces are not reset to 0 by this call.

This procedure looks for the logfile in the directory specified by the LOG_DIRECTORY system parameter, which is $ORACLE_HOME/ctx/log on UNIX. You can query the CTX_PARAMETERS view to find the current setting.

Related Topics

LOGFILENAME

Returns the filename for the current log. This procedure looks for the logfile in the directory specified by the LOG_DIRECTORY system parameter, which is $ORACLE_HOME/ctx/log on UNIX. You can query the CTX_PARAMETERS view to find the current setting.

Syntax

CTX_OUTPUT.LOGFILENAME RETURN VARCHAR2;

Returns

Log file name.

Example

declare
   logname varchar2(100);
begin
   logname := CTX_OUTPUT.LOGFILENAME;
   dbms_output.put_line('The current log file is: '||logname); 
end;

REMOVE_EVENT

Use this procedure to remove an event from the index log.

Syntax

CTX_OUTPUT.REMOVE_EVENT(event in NUMBER);

event

Specify the type of index event to remove from the log. You can remove the following events:

CTX_OUTPUT.EVENT_INDEX_PRINT_ROWID, which logs the rowid of each row after it is indexed. This is useful for debugging a failed index operation.
CTX_OUTPUT.EVENT_OPT_PRINT_TOKEN, which prints each token as it is being optimized.
CTX_OUTPUT.EVENT_INDEX_PRINT_TOKEN, which prints the each token as it is being indexed.

Example

begin

CTX_OUTPUT.REMOVE_EVENT(CTX_OUTPUT.EVENT_INDEX_PRINT_ROWID);

end;

Related Topics

See Also:

ADD_EVENT

REMOVE_TRACE

Use this procedure to disable a trace.

Syntax

CTX_OUTPUT.REMOVE_TRACE(trace_id BINARY_INTEGER);

trace_id: Specify the ID of the trace to disable. See Table 9-1, "Available Traces" for possible values.

Notes

If the trace has not been enabled, an error is raised.

Related Topics

RESET_TRACE

Use this procedure to clear a trace (that is, reset it to 0).

Syntax

CTX_OUTPUT.RESET_TRACE(trace_id BINARY_INTEGER);

trace_id: Specify the ID of the trace to reset. See Table 9-1, "Available Traces" for possible values.

Notes

If the trace has not been enabled, an error is raised.

Related Topics

START_LOG

Begin logging index and document service requests.

Syntax

CTX_OUTPUT.START_LOG(logfile in varchar2, overwrite in default true);

logfile: Specify the name of the log file. The log is stored in the directory specified by the system parameter LOG_DIRECTORY.
overwrite: Specify whether you want to overwrite or append to the original query log file specified by logfile, if it already exists. The default is to overwrite the original query log file.

Example

begin
CTX_OUTPUT.START_LOG('mylog1');
end;

Notes

Logging is independent of tracing. Logging does not have to be on to start tracing, and vice-versa.

Logging is associated with a session—it can log operations that take place within a single session, and, conversely, cannot make measurements across sessions.

Filenames used in CTX_OUTPUT.START_LOG are restricted to the following characters: alphanumeric, minus, period, space, hash, underscore, single and double quotes. Any other character in the filename will raise an error.

START_QUERY_LOG

Begin logging query requests into a query log file.

Use CTX_OUTPUT.END_QUERY_LOG to stop logging queries. Use CTX_REPORT.QUERY_LOG_SUMMARY to obtain reports on logged queries, such as which queries returned successfully the most times.

The query log includes the query string, the index name, and the timestamp of the query, as well as whether or not the query successfully returned a hit. A successful query for the phrase Blues Guitarists made at 6:46 (local time) on November 11th, 2003, would be entered into the query log in this form:

<QuerySet><TimeStamp>18:46:51 02/04/03</TimeStamp><IndexName>
IDX_SEARCH_TABLE</IndexName><Query>Blues
Guitarists</Query><ReturnHit>Yes</ReturnHit></QuerySet>

Syntax

CTX_OUTPUT.START_QUERY_LOG(logfile in varchar2, overwrite in default true);

logfile: Specify the name of the query log file. The query log is stored in the directory specified by the system parameter LOG_DIRECTORY.
overwrite: Specify whether you want to overwrite or append to the original query log file specified by logfile, if it already exists. The default is to overwrite the original query log file.

Example

begin

CTX_OUTPUT.START_QUERY_LOG('mylog1');
     < get queries >
CTX_OUTPUT.END_QUERY_LOG;

end;

Notes

Filenames used in CTX_OUTPUT.START_QUERY_LOG are restricted to the following characters: alphanumeric, minus, period, space, hash, underscore, single and double quotes. Any other character in the filename will raise an error.

Logging is associated with a session—it can log operations that take place within a single session, and, conversely, cannot make measurements across sessions.