Today the value 300 is too small to be used as a threshold.
SQL Server’s CAT also indicated that values for this counter should never quickly drop by 50% or more Several authorities on the subject, including SQL Server’s Customer Advisory Team (CAT), indicated that the value for this counter should be at least 300 for OLTP applications. Such an event would be easily detectable by following the page life expectancy counter as its value would necessarily drop
#Server 2012 r2 paging file monitor full#
As an example a missing index on a large table (table for which pages cannot fit into RAM available for SQL Server’s buffer pool) will eventually lead to a full scan which will of course lead to increased reading (problem) and flushing of potentially useful pages of other tables (aggravating problem). The relevance of monitoring this counter cannot be overstated, as a low value for it indicates that a SQL Server memory pressure, as explained above, must necessarily lead to more I/O which is, of course, the slowest component in the stack by several orders of magnitude.
So this counter indicates just how long, in seconds and on average, the pages are staying in the buffer pool and the longer an average page is living in the buffer pool, the higher the chances are that SQL Server will find it there when eventually it needs it again instead of having to read it from the disk This counter is part of SQL Server’s Buffer Manager Object and MSDN defines it as “the number of seconds a page will stay in the buffer pool without references.” Even though it doesn’t say so in its definition nor in its name, this counter actually shows the average, not some total or min/max, of the lifetime of pages in the buffer pool. These measurements are:īy far the most cited performance counter is Page Life Expectancy (aka PLE). Most important memory measurements deal with SQL Server’s buffer pool, an internal cache of database pages, SQL Server’s memory and the system’s memory. Conversely, allowing SQL Server to use more memory can help cover up lots of these and other issues Memory and the way SQL Server uses it, is right on a sort of tripoint where SQL Server, CPU and I/O meet and memory pressure may indicate missing indexes, badly designed tables, an actual lack of memory on the server for the workload it’s been tasked with, other applications running on the system, users logging onto the server and so on. Not the only thing, far from it, and some CPU, I/O and internal SQL Server counters are critically important to get the complete picture but it’s the memory counters that often show us the first indication of suboptimal performance Even a superficial reading of books and articles on SQL Server performance monitoring will tell you that SQL Server memory pressure is the first thing you should monitor.
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