SHOW TABLE STATUS Syntax-MySQL - Instablogs
SHOW TABLE STATUS Syntax-MySQL
Jayapal , Trivandrum: Mar 18 2008
Made Popular Mar 18 2008
India :

SHOW TABLE STATUS works likes SHOW TABLES, but provides a lot of information about each table. You can also get this list using the mysqlshow –status db_name command. The LIKE clause, if present, indicates which table names to match. The WHERE clause can be given to select rows using more general conditions, as discussed

SHOW TABLE STATUS returns the following fields:

Name

The name of the table.


Engine

The storage engine for the table. See Chapter 13, Storage Engines.

Version

The version number of the table’s .frm file.

Row_format

The row storage format (Fixed, Dynamic, Compressed, Redundant, Compact). Starting with MySQL/InnoDB 5.0.3, the format of InnoDB tables is reported as Redundant or Compact. Prior to 5.0.3, InnoDB tables are always in the Redundant format.

Rows

The number of rows. Some storage engines, such as MyISAM, store the exact count. For other storage engines, such as InnoDB, this value is an approximation, and may vary from the actual value by as much as 40 to 50%. In such cases, use SELECT COUNT(*) to obtain an accurate count.

The Rows value is NULL for tables in the INFORMATION_SCHEMA database.

Avg_row_length

The average row length.

Data_length

The length of the data file.

Max_data_length

The maximum length of the data file. This is the total number of bytes of data that can be stored in the table, given the data pointer size used.

Index_length

The length of the index file.

Data_free

The number of allocated but unused bytes.

Auto_increment

The next AUTO_INCREMENT value.

Create_time

When the table was created.

Update_time

When the data file was last updated. For some storage engines, this value is NULL. For example, InnoDB stores multiple tables in its tablespace and the data file timestamp does not apply.

Check_time

When the table was last checked. Not all storage engines update this time, in which case the value is always NULL.

Collation

The table’s character set and collation.

Checksum

The live checksum value (if any).

Create_options

Extra options used with CREATE TABLE. The original options supplied when CREATE TABLE is called are retained and the options reported here may differ from the active table settings and options.

Comment

The comment used when creating the table (or information as to why MySQL could not access the table information).

In the table comment, InnoDB tables report the free space of the tablespace to which the table belongs. For a table located in the shared tablespace, this is the free space of the shared tablespace. If you are using multiple tablespaces and the table has its own tablespace, the free space is for only that table. Free space means the number of completely free 1MB extents minus a safety margin. Even if free space displays as 0, it may be possible to insert rows as long as new extents need not be allocated.

For MEMORY tables, the Data_length, Max_data_length, and Index_length values approximate the actual amount of allocated memory. The allocation algorithm reserves memory in large amounts to reduce the number of allocation operations.

Beginning with MySQL 5.0.3, for NDB Cluster tables, the output of this statement shows appropriate values for the Avg_row_length and Data_length columns, with the exception that BLOB columns are not taken into account. In addition, the number of replicas is now shown in the Comment column (as number_of_replicas).

For views, all the fields displayed by SHOW TABLE STATUS are NULL except that Name indicates the view name and Comment says view.


Here is an example of using this command with php and get results...

$result = mysql_query(”SHOW TABLE STATUS FROM test;”);
while($array = mysql_fetch_array($result)) {
$total = $array[Data_length]+$array[Index_length];
echo ‘
Table: ‘.$array[Name].’
Data Size: ‘.$array[Data_length].’
Index Size: ‘.$array[Index_length].’
Total Size: ‘.$total.’
Total Rows: ‘.$array[Rows].’
Average Size Per Row: ‘.$array[Avg_row_length].’
‘;
}

?> ——————————— Jayapal

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