polish

Author: JaySon-Huang

tiflash/troubleshoot-tiflash.md

@@ -153,9 +153,9 @@ If TiFlash replicas consistently fail to be created since the TiDB cluster is de
     - If `true` is returned, go to the next step.
     - If `false` is returned, [enable the Placement Rules feature](/configure-placement-rules.md#enable-placement-rules) and go to the next step.
 
-2. Check whether the TiFlash process is working normally by the `UpTime` on the TiFlash-Summary monitoring panel.
+2. Check whether the TiFlash process is working normally by the `UpTime` on the TiFlash-Summary Grafana panel.
 
-3. Check whether the connection between TiFlash and PD is normal through `pd-ctl`.
+3. Check whether the connection between TiFlash and PD is normal.
 
     ```shell
     tiup ctl:nightly pd -u http://${pd-ip}:${pd-port} store
@@ -205,14 +205,15 @@ If none of the above configurations or TiFlash status show abnormalities, please
 
 ## Data is not replicated to TiFlash
 
-After deploying a TiFlash node and starting replication (by performing the ALTER operation), no data is replicated to it. In this case, you can identify and address the problem by following the steps below:
+After deploying a TiFlash node and starting replication by executing `ALTER TABLE ... SET TIFLASH REPLICA ...`, no data is replicated to it. In this case, you can identify and address the problem by following the steps below:
 
 1. Check whether the replication is successful by running the `ALTER table <tbl_name> set tiflash replica <num>` command and check the output.
 
     - If there is output, go to the next step.
     - If there is no output, run the `SELECT * FROM information_schema.tiflash_replica` command to check whether TiFlash replicas have been created. If not, run the `ALTER table ${tbl_name} set tiflash replica ${num}` command again
         - Check whether the DDL statement is executed as expected through [ADMIN SHOW DDL](/sql-statements/sql-statement-admin-show-ddl.md). Or there are any other DDL statement that block altering TiFlash replica statement being executed.
         - Check whether any DML statement is executed on the same table through [SHOW PROCESSLIST](/sql-statements/sql-statement-show-processlist.md) that blocks altering TiFlash replica statement being executed.
+        - If nothing is blocking the `ALTER TABLE ... SET TIFLASH REPLICA ...` being executed, go to the next step.
 
 2. Check whether TiFlash Region replication runs correctly.
 
@@ -221,7 +222,7 @@ After deploying a TiFlash node and starting replication (by performing the ALTER
    - If changes are detected, it indicates TiFlash replication is functioning normally (though potentially at a slower pace). Please refer to the "Data replication is slow" section for optimization configurations.
    - If no, TiFlash replication is abnormal. In `tidb.log`, search the log saying `Tiflash replica is not available`. Check whether `progress` of the corresponding table is updated. If not, go to the next step.
 
-3. Check whether TiDB has created any placement rule for tables.
+3. Check whether TiDB has created any placement rule for the table.
 
     Search the logs of TiDB DDL Owner and check whether TiDB has notified PD to add placement rules. For non-partitioned tables, search `ConfigureTiFlashPDForTable`. For partitioned tables, search `ConfigureTiFlashPDForPartitions`.
 
@@ -230,11 +231,13 @@ After deploying a TiFlash node and starting replication (by performing the ALTER
 
 4. Check whether PD has configured any placement rule for tables.
 
-    Run the `curl http://<pd-ip>:<pd-port>/pd/api/v1/config/rules/group/tiflash` command to view all TiFlash placement rules on the current PD. If a rule with the ID being `table-<table_id>-r` is found, the PD has configured a placement rule successfully.
+    Run the `curl http://<pd-ip>:<pd-port>/pd/api/v1/config/rules/group/tiflash` command to view all TiFlash placement rules on the current PD.
+        - If a rule with the ID being `table-<table_id>-r` is found, the PD has configured a placement rule successfully, go to the next step.
+        - If not, collect logs of the corresponding component for troubleshooting.
 
 5. Check whether the PD schedules properly.
 
-    Search the `pd.log` file for the `table-<table_id>-r` keyword and scheduling behaviors like `add operator`.
+    Search the `pd.log` file for the `table-<table_id>-r` keyword and scheduling behaviors like `add operator`. Or check whether there are `add-rule-peer` operator on the "Operator/Schedule operator create" of PD Dashboard on Grafana.
 
     - If the keyword is found, the PD schedules properly.
     - If not, the PD does not schedule properly.