Tuple logs are log files to which information about input and output tuples is output. A tuple log is output for each stream queue. You can use tuple logs for the following purposes:
For details about re-execution of queries, see 4.3.1 Re-executing queries.
The following figure shows a flow of output and display of tuple logs.
Figure 6-2 Flow of output and display of tuple logs
You specify whether or not tuple logs are to be output by using parameters that begin with tpl. in the files listed below:
For details about each file, see 8. SDP Server Definition Files.
Tuple logs are placed in a tuple buffer provided for each stream queue and then are output to file. The table below describes the tuple log output timing.
Table 6-9 Tuple log output timing
No. | Tuple log output timing | Tuple log that is output to file |
---|---|---|
1 | When the specified tpl.bufferSize parameter value is exceeded | Tuple log in the buffer |
2 | When the putEnd method is executed on an input stream queue | All tuple logs in the buffer for the input stream queue |
3 | When the putEnd method is executed on all input stream queues in a query group | All tuple logs in the buffer for the output stream queue in the query group |
4 | When a query group is terminated | All tuple logs in the buffers for the stream queues in the query group |
5 | When the SDP server is shut down | All tuple logs in the buffers for the stream queues on the SDP server |
Tuple logs are output in the wraparound mode to as many files as the value specified in the tpl.fileCount parameter. The following table describes the timing of switching tuple log files.
Table 6-10 Timing of switching tuple log files
No. | Timing of tuple log file switching | Tuple log file to be switched |
---|---|---|
1 | When the specified tpl.fileSize parameter value is exceeded | Tuple log file that has become full |
2 | When the putEnd method is executed on all input stream queues in a query group | Tuple log files for the stream queues in the query group |
Tuple logs are not output in the following cases:
The files listed below are output to the tuple log output destination directory. Note that the file access permissions depend on the user permissions used to execute the sdpstart command.
These files are output under the following names:
tpl_query-group-name-stream-name_file-serial-number
tpl_query-group-name-stream-name_file-serial-number.bkbackup-generation-number
The following describes each component of the file names:
You can check the output tuple log information by executing the sdptplls command.
For details about the sdptplls command, see sdptplls (displays tuple information) in 7. Commands.