add sysvar tidb_enable_plan_replayer_continuous_capture (#13029)

pingcap · Mar 28, 2023 · 712f07a · 712f07a
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diff --git a/sql-plan-replayer.md b/sql-plan-replayer.md
@@ -247,3 +247,15 @@ The method of downloading the file of `PLAN REPLAYER CAPTURE` is the same as tha
 > **Note:**
 >
 > The result file of `PLAN REPLAYER CAPTURE` is kept in the TiDB cluster for up to one hour. After one hour, TiDB deletes the file.
+
+## Use `PLAN REPLAYER CONTINUOUS CAPTURE`
+
+After `PLAN REPLAYER CONTINUOUS CAPTURE` is enabled, TiDB asynchronously records the applications' SQL statements with the `PLAN REPLAYER` method according to their `SQL DIGEST` and `PLAN DIGEST`. For SQL statements and execution plans that share the same DIGEST, `PLAN REPLAYER CONTINUOUS CAPTURE` does not record them repeatedly.
+
+### Enable `PLAN REPLAYER CONTINUOUS CAPTURE`
+
+`PLAN REPLAYER CONTINUOUS CAPTURE` is controlled by the system variable [`tidb_enable_plan_replayer_continuous_capture`](/system-variables.md#tidb_enable_plan_replayer_continuous_capture-new-in-v700). To enable `PLAN REPLAYER CONTINUOUS CAPTURE`, set the value of the system variable to `ON`.
+
+### View the capture results
+
+The method of viewing the capture results of `PLAN REPLAYER CONTINUOUS CAPTURE` is the same as that of [Viewing the capture results of `PLAN REPLAYER CAPTURE`](#view-the-capture-results).
diff --git a/system-variables.md b/system-variables.md
@@ -1780,16 +1780,27 @@ MPP is a distributed computing framework provided by the TiFlash engine, which a
 
 </CustomContent>
 
-### tidb_enable_plan_replayer_continues_capture
+### tidb_enable_plan_replayer_continuous_capture <span class="version-mark">New in v7.0.0</span>
 
-> **Warning:**
->
-> The feature controlled by this variable is not fully functional in the current TiDB version. Do not change the default value.
+<CustomContent platform="tidb-cloud">
 
 - Scope: SESSION | GLOBAL
 - Persists to cluster: Yes
 - Type: Boolean
 - Default value: `OFF`
+- This variable controls whether to enable the `PLAN REPLAYER CONTINUOUS CAPTURE` feature. The default value `OFF` means to disable the feature.
+
+</CustomContent>
+
+<CustomContent platform="tidb">
+
+- Scope: SESSION | GLOBAL
+- Persists to cluster: Yes
+- Type: Boolean
+- Default value: `OFF`
+- This variable controls whether to enable the [`PLAN REPLAYER CONTINUOUS CAPTURE` feature](/sql-plan-replayer.md#use-plan-replayer-continuous-capture). The default value `OFF` means to disable the feature.
+
+</CustomContent>
 
 ### tidb_enable_prepared_plan_cache <span class="version-mark">New in v6.1.0</span>