2/1/2024 0 Comments Bandwidth synonymMake sure that the application is committing the opened transactions and that it committing them in a timely mannerĬheck if there is the way to reduce the requested dataset in a way to perform data filtering on the SQL Server directly Make sure that appropriate views are created for the client application, as this can ensure that data filtering is done by the SQL Server instance and therefore the significantly lower amount of data will be send to the client application Using the read immediately and process afterwards programing method may often save users from excessive ASYNC_NETWORK_IO wait type values Pay attention to third-party applications like Microsoft Access or ORM software (aka Object relational mapping) for example, that may be requesting the large data sets that they are filtering on the client side. While investigating the excessive ASYNC_NETWORK_IO wait type values, the following should be checkedĬheck whether the application is requesting large data sets from a SQL Server instance, and then if it filters those data on the client side. So what DBAs can do when they encounter high ASYNC_NETWORK_IO wait type values on SQL Server? This involves investigating the application that is causing the excessive ASYNC_NETWORK_IO wait type values and often the coordinating with the application developers who created it. And while waiting to send a new data requested by the application to a buffer for further processing it generates the ASYNC_NETWORK_IO wait type. The server process (SPID) that is executes the batch will be forced to wait until the application manages to start processing the data stored in the buffer allowing SQL Server to send the new result set to the client (via buffer). When an application that is using the RBAR processing is forced to work with a very large database environment (VLDB), it will often encounter issues in processing data. This will allow SQL Server to send a new data set while the application is processing the data from the cached results set In such a scenario, the complete result set, available for processing, is cached and then SQL Server is notified that the data set has been “processed”. In RBAR application programming, only one row at a time is processed from the result set sent by SQL Server. Row by Agonizing Row (RBAR) processing is often the cause of such behavior and high ASYNC_NETWORK_IO wait type values. When an application requests large data result sets, slow data processing will cause data buffers to be filled, thus preventing SQL Server from sending new data to the client. The most common reason for excessive SQL Server ASYNC_NETWORK_IO wait types is that the application cannot process the data that arrives from SQL Server fast enough. This, in and of itself, will degrade the efficiency of the application. A clogged Ethernet will cause the slow data transmission back and forth from the application. This is a common scenario that may reflect bad application design, and is the most often cause of excessive ASYNC_NETWORK_IO wait type values The session must wait for the client application to process the data received from SQL Server in order to send the signal to SQL Server that it can accept new data for processing. In most cases excessive values for this wait type are not actually related to any network issues (or it is a very rare case), especially in today’s very fast Ethernet speeds of 40 Gigabit or 100 Gigabit, and those of 200 Gigabit and 400 Gigabit speed that are under development at the moment.Įxcessive ASYNC_NETWORK_IO waits could occur under two scenarios: The original name of this wait type originates from the period of the slow Ethernet speeds of 10 Megabits and 100 Megabits that are commonly in use until the mid-2000s It is important to know that ASYNC_NETWORK_IO name is adopted starting from SQL Server 2005, while in SQL Server 2000 this wait type is known as NETWORKIO. The ASYNC_NETWORK_IO wait type is one of those wait types that can be seen very often by DBAs, and it can be worrisome when excessive values occur, as it is one of the most difficult wait types to fix.
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