> ## Documentation Index > Fetch the complete documentation index at: https://planetscale.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Extensions: auto_explain > auto_explain logs execution plans for slow statements automatically to help troubleshoot query performance. export const PlatformAvailability = ({current, vitess, postgres}) => { const docsHref = path => { if (!path) return path; const normalized = path.startsWith('/') ? path : `/${path}`; return normalized; }; const labels = { vitess: 'Vitess', postgres: 'Postgres' }; if (current === 'both') { return

Vitess and Postgres

; } const hasVitess = current === 'vitess' || Boolean(vitess); const hasPostgres = current === 'postgres' || Boolean(postgres); const only = !(hasVitess && hasPostgres); const engines = []; if (current === 'vitess' || current === 'postgres') engines.push(current); if (hasVitess && current !== 'vitess') engines.push('vitess'); if (hasPostgres && current !== 'postgres') engines.push('postgres'); return

{engines.map(engine => { const isCurrent = current === engine; const href = docsHref(engine === 'vitess' ? vitess : postgres); const label = only ? `${labels[engine]} only` : labels[engine]; const state = isCurrent || !href ? 'current' : 'link'; if (isCurrent || !href) { return {label} ; } return {label} ; })}

; }; ## Dashboard Configuration This extension requires activation via the PlanetScale dashboard before it can be used. It is loaded through `session_preload_libraries` and does not require a database restart. To enable auto\_explain: From the PlanetScale organization dashboard, select the desired database Navigate to the **Clusters** page from the menu on the left Choose the branch whose extensions you'd like to configure in the "**Branch**" dropdown Select the **Extensions** tab Enable auto\_explain and configure its parameters Click **Queue extension changes** to apply the configuration Once you're ready to apply the changes, click "**Apply changes**" ## Parameters ### auto\_explain.log\_min\_duration * **Type**: Integer (milliseconds) * **Default**: `-1` * **Description**: Minimum statement duration to log a plan for. Set to `-1` to disable logging by duration. ### auto\_explain.log\_analyze * **Type**: Boolean * **Default**: `false` * **Description**: Uses `EXPLAIN ANALYZE` for logged plans to include actual execution statistics. ### auto\_explain.log\_buffers * **Type**: Boolean * **Default**: `false` * **Description**: Includes buffer usage statistics in logged plans. ### auto\_explain.log\_wal * **Type**: Boolean * **Default**: `false` * **Description**: Includes WAL usage statistics in logged plans. ### auto\_explain.log\_timing * **Type**: Boolean * **Default**: `true` * **Description**: Includes per-node timing information in logged plans. ### auto\_explain.log\_triggers * **Type**: Boolean * **Default**: `false` * **Description**: Includes trigger execution statistics in logged plans. ### auto\_explain.log\_verbose * **Type**: Boolean * **Default**: `false` * **Description**: Uses `EXPLAIN VERBOSE` output for logged plans. ### auto\_explain.log\_format * **Type**: Select * **Options**: text, xml, json, yaml * **Default**: `text` * **Description**: Output format used when logging plans. ### auto\_explain.log\_level * **Type**: Select * **Default**: `log` * **Description**: Log severity used when writing query plans. ### auto\_explain.log\_nested\_statements * **Type**: Boolean * **Default**: `false` * **Description**: Logs plans for nested statements that run inside functions. ### auto\_explain.sample\_rate * **Type**: Decimal * **Default**: `1` * **Minimum**: `0` * **Maximum**: `1` * **Description**: Fraction of statements that are sampled for plan logging. ## Usage `auto_explain` is not installed with `CREATE EXTENSION`. After enabling it in the dashboard, sessions load it through `session_preload_libraries`. You can verify and tune settings in SQL: ```sql theme={null} SHOW session_preload_libraries; SET auto_explain.log_min_duration = '250ms'; SET auto_explain.sample_rate = 0.25; ``` Logged plans appear in your cluster logs when statements match the configured thresholds. ## External Documentation For more detail about `auto_explain` behavior and parameter semantics, see the [official PostgreSQL documentation](https://www.postgresql.org/docs/current/auto-explain.html).