MySQL: TABLE_ROWS column of information_schema and count(*) are different-CodePudding

I think TABLE_ROWS column from information_schema.partitions table and result of COUNT(*) have to be same, but in my table, these values are different. Is it possible to be different?

mysql> select partition_name, partition_ordinal_position, table_rows from information_schema.partitions where table_name='lootinfo';
 ---------------- ---------------------------- ------------ 
| PARTITION_NAME | PARTITION_ORDINAL_POSITION | TABLE_ROWS |
 ---------------- ---------------------------- ------------ 
| future         |                          3 |          0 |
| p_202206       |                          1 |      10676 |
| p_202207       |                          2 |          0 |
 ---------------- ---------------------------- ------------ 
3 rows in set (0.00 sec)

mysql> select count(*) from lootinfo partition (p_202206);
 ---------- 
| count(*) |
 ---------- 
|    10360 |
 ---------- 
1 row in set (0.00 sec)

I didn't insert or delete any of rows between two queries.

CodePudding user response：

TABLES_ROWS is an estimate, and COUNT is the exact number.

According to the docs :

https://dev.mysql.com/doc/mysql-infoschema-excerpt/8.0/en/information-schema-partitions-table.html

For partitioned InnoDB tables, the row count given in the TABLE_ROWS column is only an estimated value used in SQL optimization, and may not always be exact.