Performance Counters. Microsoft SQL. Technical Data Sheet. Overview:

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1 Performance Counters Technical Data Sheet Microsoft SQL Overview: Key Features and Benefits: Key Definitions: Performance counters are used by the Operations Management Architecture (OMA) to collect data and answer the questions posed to the various devices by the polling engine to determine its state of wellbeing. These counters provide the OMA with the data and information it needs to establish how well an application, server, service or driver is performing and whether there are any issues. By comparing the counter result with the defined threshold, the OMA is able to determine a problem or predict a future problem. They are also used for capacity planning. Performance analysis Capacity planning Determine system bottlenecks Performance Counter: A performance counter is that part of a modern microprocessor or other device, system or software that measures and gathers performance relevant events of the device, system or software without affecting the performance of a Sourcing has spent a great deal of time building an expertise on this complex subject both in its OMA and its people. There are thousands of performance counters for each device, system or application and the selection of those counters which will provide the customer or technical team with the most value is where the complexity lies. To some degree, the selection of the counters is considered an art. The selection depends on what the application, device or system does for the organisation and how important that role is to the business. Monitoring for the sake of monitoring is a waste of resources, time and money. System fine-tune Application performance program. For example, one performance counter might count the number of level 1 data cache misses while another performance counter might count the number of data reads or data writes. Database Lock: Database management systems utilise locks

2 to provide concurrency control. Common uses of locks are to ensure that only one user can modify a record at a time and that data cannot be read while it is being modified. Locking mechanisms can be enforced at the row, table or page level. Database Deadlock: Client applications using the database may require exclusive access to a given table, and in order to gain exclusive access they ask for a lock. If two client applications both attempt to lock the same table at the same time, neither will receive it, there is no general way to decide who to give the lock to. In this case both clients will wait for the lock forever. Lock Waits: Indicate that at least one process is locked by the lock on another process. A request waits for a resource (a database table or a row of a table) that is locked exclusively by another user. Statistics for processes waiting on a lock. Log Buffer Waits: Statistics for processes waiting for log buffer to be available. Log Write Waits: Statistics for processes waiting for log buffer to be written. Memory Grant Queue Waits: Statistics for processes waiting for memory grant to become available. Network IO Waits: Statistics relevant to wait on network I/O. Page IO Latch Waits: Statistics relevant to page I/O latches. Page Latch Waits: Statistics relevant to page latches, not including I/O latches. Non-Page Latch Waits: Statistics relevant to non-page latches. Thread Safe Memory Waits: Statistics for processes waiting on thread-safe memory allocators. Transaction Ownership Waits: Statistics relevant to processes synchronising access to transaction. Wait For The Worker Waits: Statistics relevant to processes waiting for worker to become available. Performance Counters: The following performance counters are used by Sourcing and the OMA for the monitoring of Microsoft SQL: Page 2 of 15

3 Database Lock Instance Counters o SQL Server Average Wait Time ms: Reflects the average amount of wait time (milliseconds) for each lock request that resulted in a that could not be satisfied immediately and required the caller to wait before being granted the lock. o SQL Server Number Of Deadlocks Per Sec: Reflects the number of lock requests that resulted in a deadlock. o SQL Server Lock Waits Per Sec: Reflects the number of lock requests DBName Master o Active Transactions: Reflects the number of active update transactions for the database. o Log Cache Hit Ratio: Reflects the percentage of log cache reads that were satisfied from the log cache. o Log Flush Sec: Reflects the number of log flushes per second. o Log Flush Waits Sec: Reflects the number of commits waiting on log flush per second. o Log Flush Wait Time: Reflects the total wait time (milliseconds). o Percent Log Used: Reflects the percent of space in the log that is in use. o Transactions Per Sec: Reflects the number of transactions started for the database.

4 MSSQL Counters o Actual Buffer Pages: Reflects the number of pages in the buffer pool including database, free and stolen. o Average Latch Wait Time ms: Reflects the average latch wait time (milliseconds) for latch requests that had to o Buffer Cache Hit Ratio: Percentage of pages found in the buffer cache without having to read from disk. The ratio is the total number of cache hits divided by the total number of cache lookups since SQL Server was started. 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. Generally, you can increase the buffer cache hit ratio by increasing the amount of memory available to SQL Server. o Buffer Free List Stalls Per Sec: Reflects the number of requests that had to wait for a free page. o Buffer Free Pages: Reflects the total number of pages on all free lists. o Free Space Scans Per Sec: Reflects the number of scans per second that were initiated to search for free space within pages already allocated to an allocation unit to insert or modify record fragments. Each scan may find multiple pages. o Full Scans Per Sec: Reflects the number of unrestricted full scans. These can either be base table or full index scans. o Ideal Buffer Pages: Reflects the ideal number of pages in the buffer pool. o Index Searches Per Sec: Reflects the number of index searches. Index searches are used to start range scans, single index record fetches, and to reposition within an index. Page 4 of 15

5 o Latch Waits Per Sec: Reflects the number of latch requests that could not be granted immediately and had to wait before being granted. o Maximum Workspace Memory KB: Reflects the total amount of memory granted to executing processes. This memory is used primarily for hash, sort and create index operations. o Memory Manager Grants Pending: Reflects the current number of processes waiting for a workspace memory grant. o Page Life Expectancy: Reflects the number of seconds a page will stay in the buffer pool without references. that occur as a result of overflowing index pages. o Total Latch Wait Time ms: Reflects the total latch wait time (milliseconds) for latch requests that had to wait in the last second. o Total Server Memory: Reflects the total amount of dynamic memory the server is currently consuming. o Work Files Created Per Sec: Reflects the number of work files created per second. For example, work files could be used to store temporary results for hash joins and hash aggregates. o Work Tables Created Per Sec: Reflects the number of work tables created per second. For example, work tables could be used to store temporary results for query spool, LOB variables, XML variables, and cursors. o Page Splits Per Sec: Reflects the number of page splits per second Page 5 of 15

6 MSSQL Load o Batch Requests Sec: Reflects how busy the SQL server is. This counter measures the number of batch requests that SQL Server receives per second, and generally follows in step to how busy your server's CPUs are. Generally speaking, over 1000 batch requests per second indicates a very busy SQL Server, and could mean that if you are not already experiencing a CPU bottleneck, that you may very well soon. Of course, this is a relative number, and the bigger your hardware, the more batch requests per second SQL Server can handle. From a network bottleneck approach, a typical 100 Mbs network card is only able to handle about 3000 batch requests per second. If you have a server that is this busy, you may need to have two or more network cards, or go to a 1 Gbs network card. o Compilations Sec: This measures how many compilations are performed by SQL Server per second. Generally speaking, if this figure is over 100 compilations per second, then you may be experiencing unnecessary compilation overhead. A high number such as this might indicate that you server is just very busy, or it could mean that unnecessary compilations are being performed. For example, compilations can be forced by SQL Server if object schema changes, if previously parallelised execution plans have to run serially, if statistics are recomputed, or if a number of other things occur. In some cases, you have the power to reduce the number of unnecessary compilations.

7 MSSQL Cache Counters This is the pool of memory pages containing the execution plans for all Transact-SQL statements currently executing in the instance. An important indicator of the performance of the procedure cache is the Procedure Cache Hit Ratio performance counter. It indicates the percentage of execution plan pages found in memory as opposed to disk. o Total: Information for all types of cache instances. o Ad hoc SQL Plans: Query plans produced from an ad hoc Transact- SQL query, including autoparameterized queries. SQL Server caches the plans for ad hoc SQL statements for later reuse if the identical Transact-SQL statement is later executed. o Cursors: Ratio between cache hits and lookups. It is the ratio of the number of times an open cursor was found divided by the number of times a cursor was sought. o Execution Contexts: From a query plan, an execution context is derived. Execution contexts hold the values needed for a specific execution of a query plan. Execution contexts are also cached and reused. Each user concurrently executing a batch will have an execution context that holds data (such as parameter values) specific to their execution. Although execution contexts are reused, they are not reentrant (i.e., they are singlethreaded). That is, at any point of time, an execution context can be executing only one batch submitted by a session, and while the execution is happening, the context is not given to any other session or user. o Misc. Normalized Trees: Normalized trees for views, rules, computed columns, and check constraints.

8 o Prepared SQL Plans: Query plans that correspond to Transact-SQL statements prepared using sp_prepare, sp_cursorprepare, or auto-parameterization. Userparameterized queries (even if not explicitly prepared) are also monitored as Prepared SQL Plans. o Procedure Plans: Query plans generated by creating a stored procedure. o Replication Procedure Plans: Query plans of a replication system stored procedure. o Trigger Plans: Query plans generated by creating a trigger. MSSQL Wait Statistics SQL Server Counters o Lock Waits: Indicate that at least one process is locked by the lock on another process. A request waits for a resource (a database table or a row of a table) that is locked exclusively by another user. Statistics for processes waiting on a lock. Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to of o Log Buffer Waits: Statistics for processes waiting for log buffer to be available. Average wait time ms: Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to Page 8 of 15

9 of o Log Write Waits: Statistics for processes waiting for log buffer to be written. Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to of o Memory Grant Queue Waits: Statistics for processes waiting for memory grant to become available. Average wait time ms: Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to of processes currently waiting on the following type. Waits started per second: Number of waits started per second of the selected type of o Network IO Waits: Statistics relevant to wait on network I/O. Average Wait Time (ms) is the average wait time in milliseconds Page 9 of 15

10 for each lock request that has had to of o Page IO Latch Waits: Statistics relevant to page I/O latches. Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to Cumulative wait time ms per second: Aggregated wait time per second, for the selected type of o Page Latch Waits: Statistics relevant to page latches, not including I/O latches. Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to of o Non-Page Latch Waits: Statistics relevant to non-page latches. Average Wait Time (ms) is the average wait time in milliseconds Page 10 of 15

11 for each lock request that has had to per second, for the selected type of Waits in progress: Number of processes currently waiting on the following type. o Thread Safe Memory Waits: Statistics for processes waiting on thread-safe memory allocators. Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to of o Transaction Ownership Waits: Statistics relevant to processes synchronising access to transaction. Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to of o Wait For The Worker Waits: Statistics relevant to processes waiting for worker to become available. Page 11 of 15

12 Average Wait Time (ms) is the average wait time in milliseconds for each lock request that has had to of SQL Services Counters o Service Operating State SQL Server Agent MSSQLSERVER: Reflects the state of the SQL server agent service. The SQL Server Agent is a Microsoft Windows service that executes scheduled administrative tasks, which are called jobs. SQL Server Agent uses SQL Server to store job information. Jobs contain one or more job steps. Each step contains its own task, for example, backing up a database. SQL Server Agent can run a job on a schedule, in response to a specific event, or on demand. o Service Operating State SQL Server Browser: Reflects the state of the SQL server browser service. The SQL Server Browser listens for incoming requests for Microsoft SQL Server resources and provides information about SQL Server instances installed on the computer. o Service Operating State SQL Server Integration Services: Reflects the state of the Integration Services. Microsoft Integration Page 12 of 15

13 Services is a platform for building enterprise-level data integration and data transformations solutions. You use Integration Services to solve complex business problems by copying or downloading files, sending messages in response to events, updating data warehouses, cleaning and mining data, and managing SQL Server objects and data. o Service Operating State SQL Server MSSQLSERVER: Reflects the state of the SQL instance running on the server. o Service Operating State SQL Server VSS Writer: Reflects the state of the SQL Server VSS Writer service which provides added functionality for backup and restore of SQL Server through the Volume Shadow Copy Service framework. When running, Database Engine locks and has exclusive access to the data files. When the SQL Writer Service is not running, backup programs running in Windows do not have access to the data files, and backups must be performed using SQL Server backup. Use the SQL Writer Service to permit Windows backup programs to copy SQL Server data files while SQL Server is running. o Service Operating State SQL Server Analysis Services MSSQLSERVER: Reflects the state of the Analysis service. Microsoft SQL Server Analysis Services (SSAS) delivers online analytical processing (OLAP) and data mining functionality for business intelligence applications. Analysis Services supports OLAP by letting you design, create, and manage multidimensional structures that contain data aggregated from other data sources, such as relational databases. For data mining applications, Analysis Services lets you design, create, and visualize data mining models that are constructed from other data sources by using a wide variety of industry-standard data mining algorithms. o Service Operating State SQL Server Full Text Search MSSQLSERVER: Reflects the state of the Full Text Search service. Page 13 of 15

14 SQL Server 2008 provides the functionality for applications and users to issue full-text queries against character-based data in SQL Server tables. Before fulltext queries can be run on a given table, the database administrator must create a full-text index on the table. The full-text index includes one or more characterbased columns in the table. o Service Operating State SQL Server Reporting Services MSSQLSERVER: Reflects the state of the reporting services service. SQL Server Reporting Services is a comprehensive, serverbased solution that enables the creation, management, and delivery of both traditional, paper-oriented reports and interactive, Web-based reports. An integrated part of the Microsoft Business Intelligence framework, Reporting Services combines the data management capabilities of SQL Server and Microsoft Windows Server with familiar and powerful Microsoft Office System applications to deliver real-time information to support daily operations and drive decisions. o Service Operating State MSSQL Server OLAP Service: Reflects the state of the OLAP service. OLAP Services is a fully featured OLAP capability that is a component of Microsoft SQL Server. OLAP Services includes a middle-tier server that allows users to perform sophisticated analyses on large volumes of data with exceptional performance. A second feature of OLAP Services is a client cache and calculation engine called Microsoft PivotTable Service, which helps improve performance and reduce network traffic. PivotTable Service allows users to conduct analyses while disconnected from the corporate network. OLAP is a key component in the data warehousing Page 14 of 15

15 process, and OLAP Services provides essential functionality for a wide array of applications ranging from corporate reporting to advanced decision support. Technical Specifications: Contact Information: Learn More: Microsoft SQL performance counters. Sourcing Sales Department Daniel Lorenzo Mike Tel: Tel: Tel: Mail: daniel@sourcing.co.za Mail: lorenzo@sourcing.co.za Mail: mike@sourcing.co.za For more information, please visit our website on or contact us on requests@sourcing.co.za or Page 15 of 15