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performance Metricset fetches information from what’s commonly known as Performance Counters in MSSQL.

We fetch the following data:

• page_splits_per_sec: Number of page splits per second that occur as the result of overflowing index pages.
• lock_waits_per_sec: Number of lock requests per second that required the caller to wait.
• user_connections: Total number of user connections
• transactions: Total number of transactions
• active_temp_tables: Number of temporary tables/table variables in use.
• connections_reset_per_sec: Total number of logins started from the connection pool.
• logins_per_sec: Total number of logins started per second. This does not include pooled connections.
• logouts_per_sec: Total number of logout operations started per second.
• recompilations_per_sec: Number of statement recompiles per second. Counts the number of times statement recompiles are triggered. Generally, you want the recompiles to be low.
• compilations_per_sec: Number of SQL compilations per second. Indicates the number of times the compile code path is entered. Includes compiles caused by statement-level recompilations in SQL Server. After SQL Server user activity is stable, this value reaches a steady state.
• batch_requests_per_sec: Number of Transact-SQL command batches received per second. This statistic is affected by all constraints (such as I/O, number of users, cache size, complexity of requests, and so on). High batch requests mean good throughput.
• cache_hit.pct: The ratio is the total number of cache hits divided by the total number of cache lookups over the last few thousand page accesses. After a long period of time, the ratio moves very little. Because reading from the cache is much less expensive than reading from disk, you want this ratio to be high
• page_life_expectancy.sec: Indicates the number of seconds a page will stay in the buffer pool without references (in seconds).
• buffer.checkpoint_pages_per_sec: Indicates the number of pages flushed to disk per second by a checkpoint or other operation that require all dirty pages to be flushed.
• buffer.database_pages: Indicates the number of pages in the buffer pool with database content.
• buffer.target_pages: Ideal number of pages in the buffer pool.