The INNODB_SYS_TABLES table provides metadata
about InnoDB tables, equivalent to the
information from the SYS_TABLES table in the
InnoDB data dictionary.
For related usage information and examples, see Section 14.15.3, “InnoDB INFORMATION_SCHEMA System Tables”.
Table 21.22 INNODB_SYS_TABLES Columns
| Column name | Description |
|---|---|
TABLE_ID | An identifier for each InnoDB table that is unique
across all databases in the instance. |
NAME | The name of the table. Preceded by the database name where appropriate,
for example test/t1.
InnoDB system table names are in all
uppercase. Names of databases and user tables are in the
same case as they were originally defined, possibly
influenced by the
lower_case_table_names
setting. |
FLAG | This value provides bit level information about table format and storage
characteristics including row format, compressed page size
(if applicable), and whether or not the DATA
DIRECTORY clause was used with
CREATE TABLE or
ALTER TABLE. |
N_COLS | The number of columns in the table. The number reported includes three
hidden columns that are created by
InnoDB (DB_ROW_ID,
DB_TRX_ID, and
DB_ROLL_PTR). |
SPACE | An identifier for the tablespace where the table resides. 0 means the
InnoDB
system
tablespace. Any other number represents a table
created in
file-per-table
mode with a separate .ibd file. This
identifier stays the same after a
TRUNCATE TABLE statement.
Other than the zero value, this identifier is unique for
tables across all the databases in the instance. |
FILE_FORMAT | The table's file format (Antelope or Barracuda). |
ROW_FORMAT | The table's row format (Compact, Redundant, Dynamic, or Compressed). |
ZIP_PAGE_SIZE | The zip page size. Only applies to tables that use the Compressed row format. |
Example:
mysql> SELECT * FROM INFORMATION_SCHEMA.INNODB_SYS_TABLES WHERE TABLE_ID = 74\G
*************************** 1. row ***************************
TABLE_ID: 74
NAME: test/t1
FLAG: 1
N_COLS: 6
SPACE: 60
FILE_FORMAT: Antelope
ROW_FORMAT: Compact
ZIP_PAGE_SIZE: 0
Notes:
Use DESCRIBE or
SHOW COLUMNS to view additional
information about the columns of this table including data
types and default values.
You must have the PROCESS
privilege to query this table.
Interpreting the INNODB_SYS_TABLES.FLAG Column Value:
The INNODB_SYS_TABLES.FLAG column provides
bit-level information about the table's format and storage
characteristics. You can interpret the FLAG
column value by adding together the applicable decimal numeric
values that are provided in the following table.
Table 21.23 Bit Position Values for Interpreting INNODB_SYS_TABLES FLAG Column Data
| Bit Position | Description | Decimal Numeric Value |
|---|---|---|
| 0 | This bit is set if the row format is not REDUNDANT.
In other words, it is set if the row format is
COMPACT, DYNAMIC or
COMPRESSED. |
|
| 1-4 | These four bits contain a small number that represents the compressed
page size of the table. The
INNODB_SYS_TABLES.ZIP_PAGE_SIZE field
also reports the compressed page size, if applicable. |
|
| 5 | This bit is set if the row format is DYNAMIC or
COMPRESSED. |
|
| 6 | This bit is set if the DATA DIRECTORY option is used
with CREATE TABLE or
ALTER TABLE. This bit is
set for file-per-table tablespaces that are located in
directories other than the default data directory
(datadir). For these
tables, a
|
|
In the following, table t1 uses
ROW_FORMAT=DYNAMIC and has a
FLAG value of 33. Based on the information in
the preceding table, we can see that bit position 0 would be set
to 1, and bit position 5 would be set to 32 for a table with a
DYNAMIC row format. These values add up to a
FLAG value of 33.
mysql>use test;Database changed mysql>SET GLOBAL innodb_file_format=Barracuda;Query OK, 0 rows affected (0.00 sec) mysql>CREATE TABLE t1 (c1 int) ROW_FORMAT=DYNAMIC;Query OK, 0 rows affected (0.02 sec) mysql>SELECT * FROM INFORMATION_SCHEMA.INNODB_SYS_TABLES WHERE NAME LIKE 'test/t1'\G*************************** 1. row *************************** TABLE_ID: 89 NAME: test/t1 FLAG: 33 N_COLS: 4 SPACE: 75 FILE_FORMAT: Barracuda ROW_FORMAT: Dynamic ZIP_PAGE_SIZE: 0 1 row in set (0.00 sec)