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Windows server memory monitor3/9/2023 This is simply because if a request comes in for that page, it can be read from the cache rather than searching on the disk and ultimately reduce I/O. So, essentially, we want the page to stay in the buffer for as long as possible because it will lead to high performance. If I’d have to choose one counter, this metric is the one that all SQL Server monitoring tools should be able to track. It represents the number of seconds a page will stay in the buffer pool without the references. SQLServer:Buffer Manager/Page life expectancy – this is probably the most popular performance counter when it comes to memory in SQL Server. We always want this to be extremely high. I’d say that if that ratio is less than 95% than the server is under memory pressure. SQLServer:Buffer Manager/Buffer cache hit ratio – this represents a percentage of how often SQL Server can find data pages in memory as opposed to fetching them from the disk. The default memory threshold value is 100 MB. Memory available megabytes – this is just a great all around counter especially if we track it for a long time because we can find out what thresholds are for memory. Moving on, let’s take a look at some counters for performance monitoring and SQL Server monitoring tools that can be used to track them: If both flags are zero, you’re in good shape. process_virtual_memory_low – indicates that low virtual memory condition has been detected.process_physical_memory_low – indicates that the process is responding to low physical memory notification.physical_memory_in_use_kb – indicates the process working set in KB.This will return flags to let us know if physical and virtual process memory for SQL Server is low: Let’s fire up SSMS and execute some queries, see what those DMVs will return. The three commonly used DMVs in SQL Server for memory performance are: Most of you knows what DMVs are, but for those who doesn’t, DMVs are views and functions that return server state information which can be used to monitor the health of a server instance, diagnose problems, etc. So, let’s get started with the Dynamic Management Views AKA DMVs. Tools for performance monitoring Dynamic management views If you’ve troubleshooted memory issue before, then you probably encountered some of the symptoms like system wide performance decrease and I/O increase. Hopefully, this will be a short article rather than a long one like I did with disk I/O performance but this stuff is essential to get the complete picture and take all things into account when troubleshooting performace issues. In such cases, memory pressure can occur because SQL Server simply cannot allocate enough memory. One of the obvious problems with memory that doesn’t really require any SQL Server monitoring tool to be detected is when the system simply doesn’t have enough random-access memory AKA RAM. Therefore, feel free to check out initial write-up at the following link: SQL Server monitoring tools for disk I/O performance Also, because issues described with the disk I/O performance can be manifested from memory issues. This article can be read independently but to get the full picture it’s recommended that part one is read first. The first article SQL Server monitoring tools for disk I/O performance is about how to detect and solve high input/output on hard disk subsystems when doing too much work during peak or maintenance times. This article is the sequel in a series about SQL Server monitoring tools and common performance issues.
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