update information-schema/information-schema-tiflash-replica.md (pingcap#10458)

Author: qiancai

information-schema/information-schema-tiflash-replica.md

@@ -28,3 +28,13 @@ DESC tiflash_replica;
 +-----------------+-------------+------+------+---------+-------+
 7 rows in set (0.01 sec)
 ```
+
+Fields in the `TIFLASH_REPLICA` table are described as follows:
+
+- `TABLE_SCHEMA`: the name of the database to which the table belongs.
+- `TABLE_NAME`: the name of the table.
+- `TABLE_ID`: the internal ID of the table, which is unique within a TiDB cluster.
+- `REPLICA_COUNT`: the number of TiFlash replicas.
+- `LOCATION_LABELS`: the LocationLabelList that is set when a TiFlash replica is created.
+- `AVAILABLE`: indicates whether the TiFlash replica of the table is available. When the value is `1` (available), the TiDB optimizer can intelligently choose to push down queries to TiKV or TiFlash based on query cost. When the value is `0` (unavailable), TiDB will not push down queries to TiFlash. Once the value of this field becomes `1` (available), it will not change anymore.
+- `PROGRESS`: the replication progress of TiFlash replicas, with the accuracy to two decimal places and at the minute level. The scope of this field is `[0, 1]`. When the `AVAILABLE` field is `1` and `PROGRESS` is less than 1, the TiFlash replica is far behind TiKV, and the queries pushed down to TiFlash will probably fail due to timeout of waiting for data replication.

quick-start-with-htap.md

@@ -161,8 +161,8 @@ SELECT * FROM information_schema.tiflash_replica WHERE TABLE_SCHEMA = 'test' and
 
 In the result of the above statements:
 
-- `AVAILABLE` indicates whether the TiFlash replica of a specific table is available or not. `1` means available and `0` means unavailable. Once a replica becomes available, this status does not change any more. If you use DDL statements to modify the number of replicas, the replication status will be recalculated.
-- `PROGRESS` means the progress of the replication. The value is between 0.0 and 1.0. 1 means at least one replica is replicated.
+- `AVAILABLE` indicates whether the TiFlash replica of a specific table is available or not. `1` means available and `0` means unavailable. Once the `AVAILABLE` field becomes `1`, this status does not change anymore.
+- `PROGRESS` means the progress of the replication. The value is between 0.0 and 1.0. 1 means that the replication progress of the TiFlash replica is complete.
 
 ### Step 5. Analyze data faster using HTAP