ps_trace_thread

The ps_trace_thread procedure captures a trace of Performance Schema instrumentation for a specific thread and dumps it to a .dot formatted graph file.

Syntax

ps_trace_thread(thread_id, outfile, max_runtime, interval, start_fresh, auto_setup, debug)

Description

ps_trace_thread is a stored procedure available with the Sys Schema.

Parameters:

• thread_id INT: The thread to trace.

• outfile VARCHAR(255): Name of the .dot file to be create.

• max_runtime DECIMAL(20,2): Maximum time in seconds to collect data. Fractional seconds can be used, and NULL results in data being collected for the default sixty seconds.

• interval DECIMAL(20,2): Time in seconds to sleep between data collection. Fractional seconds can be used, and NULL results in the sleep being the default one second.

• start_fresh BOOLEAN: Whether to reset all Performance Schema data before tracing.

• auto_setup BOOLEAN: Whether to disable all other threads, enable all instruments and consumers, and reset the settings at the end of the run.

• debug BOOLEAN: Whether to include file:lineno information in the graph.

Dumps all Performance Schema data for an instrumented thread to a .dot formatted graph file (for use with the DOT graph description language). All returned result sets should be used for a complete graph.

Session binary logging is disabled during execution, by adjusting the sql_log_bin session value (note the permissions required).

Examples

CALL sys.ps_trace_thread(25, CONCAT('/tmp/stack-', REPLACE(NOW(), ' ', '-'), '.dot'), 
  NULL, NULL, TRUE, TRUE, TRUE);

--------------------+
| summary            |
+--------------------+
| Disabled 0 threads |
+--------------------+

+---------------------------------------------+
| Info                                        |
+---------------------------------------------+
| Data collection starting for THREAD_ID = 25 |
+---------------------------------------------+

+-----------------------------------------------------------+
| Info                                                      |
+-----------------------------------------------------------+
| Stack trace written to /tmp/stack-2023-04-05-19:06:29.dot |
+-----------------------------------------------------------+

+-------------------------------------------------------------------+
| Convert to PDF                                                    |
+-------------------------------------------------------------------+
| dot -Tpdf -o /tmp/stack_25.pdf /tmp/stack-2023-04-05-19:06:29.dot |
+-------------------------------------------------------------------+

+-------------------------------------------------------------------+
| Convert to PNG                                                    |
+-------------------------------------------------------------------+
| dot -Tpng -o /tmp/stack_25.png /tmp/stack-2023-04-05-19:06:29.dot |
+-------------------------------------------------------------------+

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