Optimizer Trace
Optimizer trace, which records how the optimizer builds a query's execution plan.
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Optimizer trace, which records how the optimizer builds a query's execution plan.
Shows a complete optimizer trace example, from enabling optimizer_trace to reading the resulting JSON from INFORMATION_SCHEMA.OPTIMIZER_TRACE.
Explains how to collect large optimizer traces by raising max_allowed_packet and optimizer_trace_max_mem_size.
Provides guidelines for server developers on what and how to write to the optimizer trace, including keeping the JSON valid.
Guides you through reading the JSON optimizer trace, using a simple query to illustrate the join_preparation and join_optimization steps.
Introduces optimizer trace, which produces a JSON document of the optimizer's decisions for SELECT/UPDATE/DELETE queries, its system variables, and the INFORMATION_SCHEMA.OPTIMIZER_TRACE table.
Links to external optimizer trace resources, including a MariaDB Fest 2020 walkthrough talk and the opttrace processing tool.
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