Chapter 8 Tracing the Optimizer

Table of Contents     [+/-]

8.1 Typical Usage

8.2 System Variables Controlling the Trace

8.3 The INFORMATION_SCHEMA.OPTIMIZER_TRACE Table

8.4 Traceable Queries

8.5 Automatic Trace Purging

8.6 Tuning Trace Purging

8.7 Tracing Memory Usage

8.8 Privilege Checking

8.9 Interaction with the --debug Option

8.10 The optimizer_trace System Variable

8.11 The end_markers_in_json System Variable

8.12 Selecting Optimizer Features to Trace

8.13 General Trace Structure

8.14 Example

8.15 Nicely Displaying a Trace

8.16 Preventing Use of Optimizer Trace

8.17 Testing

8.18 Implementation

Since milestone version 5.6.3, a new tracing capability has been added to the MySQL optimizer. The interface is provided by a set of optimizer_trace_xxx system variables and the INFORMATION_SCHEMA.OPTIMIZER_TRACE table, but is subject to change.