Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

How can I tell when a MySQL table was last updated?

Tags:

sql

mysql

People also ask

How can I tell when a table was last updated?

If a user wants to find out when was the last table updated he can query dynamic management view (DMV) – sys. dm_db_index_usage_stats and easily figure out when was the table updated last.

How can I tell when a table was last analyzed in MySQL?

If you have the general log enabled, simply do a grep -i "analyze table" against the general log file and locate the timestamp just about the command.

Does MySQL have timestamp?

MySQL retrieves and displays DATETIME values in ' YYYY-MM-DD hh:mm:ss ' format. The supported range is '1000-01-01 00:00:00' to '9999-12-31 23:59:59' . The TIMESTAMP data type is used for values that contain both date and time parts. TIMESTAMP has a range of '1970-01-01 00:00:01' UTC to '2038-01-19 03:14:07' UTC.

What function finds current date in MySQL?

MySQL CURDATE() Function The CURDATE() function returns the current date. Note: The date is returned as "YYYY-MM-DD" (string) or as YYYYMMDD (numeric).


In later versions of MySQL you can use the information_schema database to tell you when another table was updated:

SELECT UPDATE_TIME
FROM   information_schema.tables
WHERE  TABLE_SCHEMA = 'dbname'
   AND TABLE_NAME = 'tabname'

This does of course mean opening a connection to the database.


An alternative option would be to "touch" a particular file whenever the MySQL table is updated:

On database updates:

  • Open your timestamp file in O_RDRW mode
  • close it again

or alternatively

  • use touch(), the PHP equivalent of the utimes() function, to change the file timestamp.

On page display:

  • use stat() to read back the file modification time.

I'm surprised no one has suggested tracking last update time per row:

mysql> CREATE TABLE foo (
  id INT PRIMARY KEY
  x INT,
  updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP 
                     ON UPDATE CURRENT_TIMESTAMP,
  KEY (updated_at)
);

mysql> INSERT INTO foo VALUES (1, NOW() - INTERVAL 3 DAY), (2, NOW());

mysql> SELECT * FROM foo;
+----+------+---------------------+
| id | x    | updated_at          |
+----+------+---------------------+
|  1 | NULL | 2013-08-18 03:26:28 |
|  2 | NULL | 2013-08-21 03:26:28 |
+----+------+---------------------+

mysql> UPDATE foo SET x = 1234 WHERE id = 1;

This updates the timestamp even though we didn't mention it in the UPDATE.

mysql> SELECT * FROM foo;
+----+------+---------------------+
| id | x    | updated_at          |
+----+------+---------------------+
|  1 | 1235 | 2013-08-21 03:30:20 | <-- this row has been updated
|  2 | NULL | 2013-08-21 03:26:28 |
+----+------+---------------------+

Now you can query for the MAX():

mysql> SELECT MAX(updated_at) FROM foo;
+---------------------+
| MAX(updated_at)     |
+---------------------+
| 2013-08-21 03:30:20 |
+---------------------+

Admittedly, this requires more storage (4 bytes per row for TIMESTAMP).
But this works for InnoDB tables before 5.7.15 version of MySQL, which INFORMATION_SCHEMA.TABLES.UPDATE_TIME doesn't.


I don't have information_schema database, using mysql version 4.1.16, so in this case you can query this:

SHOW TABLE STATUS FROM your_database LIKE 'your_table';

It will return these columns:

| Name      | Engine | Version | Row_format | Rows | Avg_row_length 
| Data_length | Max_data_length | Index_length | Data_free | Auto_increment
| Create_time | Update_time | Check_time | Collation
| Checksum | Create_options | Comment |

As you can see there is a column called: "Update_time" that shows you the last update time for your_table.


The simplest thing would be to check the timestamp of the table files on the disk. For example, You can check under your data directory

cd /var/lib/mysql/<mydatabase>
ls -lhtr *.ibd

This should give you the list of all tables with the table when it was last modified the oldest time, first.


For a list of recent table changes use this:

SELECT UPDATE_TIME, TABLE_SCHEMA, TABLE_NAME
FROM information_schema.tables
ORDER BY UPDATE_TIME DESC, TABLE_SCHEMA, TABLE_NAME