From cf7b79d171d198393f221d41a71c2b12f7466a75 Mon Sep 17 00:00:00 2001 From: JoyinQ <56883733+Joyinqin@users.noreply.github.com> Date: Mon, 14 Sep 2020 14:16:10 +0800 Subject: [PATCH] cherry pick #3895 to release-2.1 Signed-off-by: ti-srebot --- statistics.md | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/statistics.md b/statistics.md index 192c093cee622..f15ea24712252 100644 --- a/statistics.md +++ b/statistics.md @@ -49,7 +49,11 @@ Three system variables related to automatic update of statistics are as follows: When the ratio of the number of modified rows to the total number of rows of `tbl` in a table is greater than `tidb_auto_analyze_ratio`, and the current time is between `tidb_auto_analyze_start_time` and `tidb_auto_analyze_end_time`, TiDB executes the `ANALYZE TABLE tbl` statement in the background to automatically update the statistics of this table. -When the query is executed, TiDB collects feedback with the probability of `feedback-probability` and uses it to update the histogram and Count-Min Sketch. You can modify the value of `feedback-probability` in the configuration file. The default value is `0.0`. +When the query is executed, TiDB collects feedback with the probability of `feedback-probability` and uses it to update the histogram and Count-Min Sketch. You can modify the value of `feedback-probability` in the configuration file. The default value is `0.05`. You can set the value to `0.0` to disable this feature. + +> **Note:** +> +> If you set the value of `feedback-probability` to `0` in the configuration file, a failure will occur and an error will be reported. To disable `feedback-probability`, you need to set the value to `0.0`. ### Control `ANALYZE` concurrency