Wait Type PAGEIOLATCH_SH

The wait type PAGEIOLATCH_SH is ranked #18 by Stedman Solutions and Database Health Monitor.

Wait statistics, in the context of SQL Server, refer to the amount of time that a query spends waiting to access data in the database. When a client application requests data from the database, the request is placed in a queue and the client application must wait for its turn to access the data. The time that the query spends waiting is called a "wait" and is tracked by SQL Server. This information can be used to identify potential performance bottlenecks and optimize the performance of the database. Wait statistics are commonly used by database administrators to diagnose and troubleshoot performance issues in SQL Server.


SQL Server PAGEIOLATCH_SH wait types occur when a transaction is waiting for a shared (read) lock on a page in a database file. This type of lock is used to ensure that multiple transactions can read the same data at the same time, but only one transaction can modify the data at a time.

When a transaction needs to read data from a page in a database file, it first checks to see if there are any existing locks on that page. If there are no locks, the transaction can proceed with the read. If there are existing locks, however, the transaction must wait for those locks to be released before it can read the data.

This waiting period can cause performance issues if it lasts for too long. To avoid these issues, it is important to monitor your SQL Server for PAGEIOLATCH_SH wait types and take steps to reduce the amount of time that transactions spend waiting for locks.

One way to do this is to make sure that your transactions acquire and release locks as quickly as possible. This can be accomplished by using the right isolation level for your transactions and by ensuring that your transactions are short and to the point.

Another way to reduce the amount of time that transactions spend waiting for locks is to optimize the way that data is accessed in your database. This can be done by using the right indexing strategy and by properly organizing the data in your database files.

Overall, SQL Server PAGEIOLATCH_SH wait types can be a sign of potential performance issues in your database. By monitoring for these wait types and taking steps to reduce the amount of time that transactions spend waiting for locks, you can improve the performance of your SQL Server and ensure that your database runs smoothly.

Applies to

Related Waits

PAGEIOLATCH_DT
PAGEIOLATCH_EX
PAGEIOLATCH_KP
PAGEIOLATCH_NL
PAGEIOLATCH_UP

See Also


All Wait Types