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You are tuning the performance of a virtual machines that hosts a Microsoft SQL Server instance.

The virtual machine originally had four CPU cores and now has 32 CPU cores.

The SQL Server instance uses the default settings and has an OLTP database named db1. The largest table in db1 is a key value store table named table1.

Several reports use the PIVOT statement and access more than 100 million rows in table1.

You discover that when the reports run, there are PAGELATCH_IO waits on PFS pages 2:1:1, 2:2:1, 2:3:1, and 2:4:1 within the tempdb database.

You need to prevent the PAGELATCH_IO waits from occurring.

Solution: You add more files to db1.

Does this meet the goal?

A. Yes

B. No

Explanation:

From SQL Server-s perspective, you can measure the I/O latency from sys.dm_os_wait_stats. If you consistently see high waiting for PAGELATCH_IO, you can benefit from a faster I/O subsystem for SQL Server.

A cause can be poor design of your database – you may wish to split out data located on hot pages, which are accessed frequently and which you might identify as the causes of your latch contention. For example, if you have a currency table with a data page containing 100 rows, of which 1 is updated per transaction and you have a transaction rate of 200/sec, you could see page latch queues of 100 or more. If each page latch wait costs just 5ms before clearing, this represents a full half-second delay for each update. In this case, splitting out the currency rows into different tables might prove more performant (if less normalized and logically structured).

References: https://www.mssqltips.com/sqlservertip/3088/explanation-of-sql-server-io-and-latches/