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11g Release 2 (11.2)

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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 or to enable error tracing for Oracle Text errors.

Syntax

CTX_OUTPUT.ADD_EVENT(event in NUMBER, errnum in NUMBER := null);
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.

  • CTX_OUTPUT.EVENT_DRG_DUMP_ERRORSTACK, which prints the stack trace for the specified DRG error in the log. An error will be raised if errnum is not specified.

errnum

Specify the DRG error number for a CTX_OUTPUT.EVENT_DRG_DUMP_ERRRORSTACK event.

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 LOBs

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.

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 ctx_output.enable_query_stats is turned on for the index.

Note:

Accessing the query stats metadata only works when ctx_output.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_output.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_OUTPUT.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, then the column displays YES; if not, then 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, then an error is thrown.

Statistics collection has a minimal effect 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.

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.

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.

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.

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.