diff --git a/information-schema/information-schema-table-storage-stats.md b/information-schema/information-schema-table-storage-stats.md
index f368bcecc10b6..8c17096251b57 100644
--- a/information-schema/information-schema-table-storage-stats.md
+++ b/information-schema/information-schema-table-storage-stats.md
@@ -59,5 +59,5 @@ Fields in the `TABLE_STORAGE_STATS` table are described as follows:
 * `PEER_COUNT`: The number of replicas of the table.
 * `REGION_COUNT`: The number of Regions.
 * `EMPTY_REGION_COUNT`: The number of Regions that do not contain data in this table.
-* `TABLE_SIZE`: The total size of the table, in the unit of MiB.
+* `TABLE_SIZE`: The total size of the table, in the unit of MiB. Note that this value is a logical estimate based on table statistics and does not represent the actual compressed physical size in storage.
 * `TABLE_KEYS`: The total number of records in the table.
diff --git a/information-schema/information-schema-tables.md b/information-schema/information-schema-tables.md
index d3d3613f2f25f..6e755d55e73f8 100644
--- a/information-schema/information-schema-tables.md
+++ b/information-schema/information-schema-tables.md
@@ -102,9 +102,9 @@ The description of columns in the `TABLES` table is as follows:
 * `ROW_FORMAT`: The row format. The value is currently `Compact`.
 * `TABLE_ROWS`: The number of rows in the table in statistics.
 * `AVG_ROW_LENGTH`: The average row length of the table. `AVG_ROW_LENGTH` = `DATA_LENGTH` / `TABLE_ROWS`.
-* `DATA_LENGTH`: Data length. `DATA_LENGTH` = `TABLE_ROWS` \* the sum of storage lengths of the columns in the tuple. The replicas of TiKV are not taken into account.
+* `DATA_LENGTH`: Data length. `DATA_LENGTH` = `TABLE_ROWS` \* the sum of storage lengths of the columns in the tuple. The replicas of TiKV are not taken into account. Note that this value is a logical estimate based on table statistics and does not represent the actual compressed physical size in storage.
 * `MAX_DATA_LENGTH`: The maximum data length. The value is currently `0`, which means the data length has no upper limit.
-* `INDEX_LENGTH`: The index length. `INDEX_LENGTH` = `TABLE_ROWS` \* the sum of lengths of the columns in the index tuple. The replicas of TiKV are not taken into account.
+* `INDEX_LENGTH`: The index length. `INDEX_LENGTH` = `TABLE_ROWS` \* the sum of lengths of the columns in the index tuple. The replicas of TiKV are not taken into account. Note that this value is a logical estimate based on table statistics and does not represent the actual compressed physical size in storage.
 * `DATA_FREE`: Data fragment. The value is currently `0`.
 * `AUTO_INCREMENT`: The current step of the auto- increment primary key.
 * `CREATE_TIME`: The time at which the table is created.