SQL Server Trace Flags - SQLServer. Central. Trace flags can be used to alter the behavior of SQL Server and they can help when diagnosing performance issues as well. During the course of days I've come across cases from where I learnt about them & their purpose; certainly do let me know for any corrections that I may have missed out. They are used in this post for discussion purposes only and may not be supported in future versions. KB 2. 03. 78. 7. SQL 6. Turns off ANSI select characteristics. KB 1. 52. 03. 2. Consider using when replaying against SQL 8. KB 9. 26. 29. 2. SQL 6. Backward compatibility switch that enables non- ansi standard behavior. KB 1. 95. 56. 5. SQL 6. Provides backward compatibility for the set user statement. KB 1. 60. 73. 2. SET QUOTED IDENTIFIER ON. KB 9. 45. 89. 2. SQL 9 – Query may run much slower when compared to SQL 8 when you use a cursor to run the query. KB 9. 51. 18. 4. Tells SQL Server to use correlated sub- queries in Non- ANSI standard backward compatibility mode. When set, SQL Server has the same nullability violation behavior as that of a ver 4. Processing of the entire batch is terminated if the nullability error (inserting NULL into a NOT NULL field) can be detected at compile time. By default, SQL Server checks for and allows interim constraint violations. An interim constraint violation is caused by a change that removes the violation such that the constraint is met, all within a single statement and transaction. SQL Server checks for interim constraint violations for self- referencing DELETE statements, INSERT, and multi- row UPDATE statements. This checking requires more work tables. With this trace flag you can disallow interim constraint violations, thus requiring fewer work tables. This flag avoids that. For more information about . Scope: global or session. SQL 7 – Trailing spaces are no longer truncated from literal strings in CASE statements. Error Identifier / Description Code Severity / Facility Code; ERROR. SAP Adaptive Server Enterprise 16.0 Release Bulletin SAP Adaptive Server Enterprise 16.0 for HP-UX Release Bulletin SAP Adaptive Server Enterprise 16.0 for IBM AIX. I keep getting error 1603 while trying to install vCenter 5.5. Please see the log === Verbose logging started: 9/23/2013 11:30:04 Build type: SHIP. My First SharePoint 2013 Installation. We all remember our first time, whatever that means. In this blog post I want to walk you through your first SharePoint 2013. Prints information about whether the statistics page is used, the actual selectivity (if available), and what SQL Server estimated the physical and logical I/O would be for the indexes. Index selection information is also available in a more readable format using SET SHOWPLAN. To see join- order heuristics use flag 3. SQL Server uses join- order heuristics to reduce the no’ of permutations when using the best join order. Shows a detailed description of the various update methods used. Instructs server to use arithmetic averaging when calculating density instead of a geometric weighted average when updating statistics. Useful for building better stats when an index has skew on the leading column. Use only for updating the stats of a table/index with known skewed data. One can also use SET FORCEPLAN ON to disable the costing of pseudo- merge joins because the query is forced to use the order specified in the FROM clause. Any comparison of variables and parameters that contain a NULL always results in a NULL. A ghost record is the result of a delete operation. When you delete a record, the deleted record is kept as a ghost record. Later, the deleted record is purged by the ghost record removal process. When you disable this process, the deleted record is not purged. Therefore, the space that the deleted record consumes is not freed. This behavior affects space consumption and the performance of scan operations. SCOPE: Global. If you turn off this trace flag, the ghost record removal process works correctly. KB 9. 20. 09. 3. SQL 9 – Performance of INSERT operations against a table with an identity column may be slow when compared to SQL 8. KB 9. 40. 54. 5. Turn off transaction logging for the entire SQL dataserver. This is useful to catch cases where pages are being corrupted in memory and then written out to disk with a new page checksum. When they're read back in the checksum will look correct, but the page is corrupt (because of the previous memory corruption). This page auditing goes someway to catching this - especially on non- Enterprise Edition systems that don't have the 'checksum sniffer'. SQL Server 8 (with service pack 4) and SQL Server 9 can perform latch enforcement for data pages found in the buffer pool cache. Latch enforcement changes the virtual memory protection state while database page status changes from . If an attempt is made to modify a data page while latch enforcement is set, it causes an exception and creates a mini- dump in SQL Server installation's LOG directory. Microsoft support can examine the contents of such mini- dump to determine the cause of the exception. In order to modify the data page the connection must first acquire a modification latch. Once the data modification latch is acquired the page protection is changed to read- write. Once the modification latch is released the page protection changes back to read- only. The page size varies depending on the hardware platform, but the page size may be from 2 MB to 1. MB. Large pages are allocated at startup and are kept throughout the lifetime of the process. Trace flag 8. 34 improves performance by increasing the efficiency of the translation look- aside buffer (TLB) in the CPU. Applies only to 6. Lock pages in memory right granted to turn this on. It may prevent the server from starting if memory is fragmented and large pages cannot be allocated. Therefore its better suited dedicated hosts. Scope STARTUP. You can use trace flag 8. AWE mode. Scope Startup. Additionally, the larger I/O extent reads improve the initial query compilation and the response time when SQL Server starts. KB 9. 12. 32. 2. Use sys. This turns on Lock pages in memory. Scope Startup KB 9. When sql server holds at the script upgrade mode. Mode examples details at. Sort=Most. Useful& Page. Index=1. &. http: //blogs. There is now a cache of temp tables. When a new temp table is created on a cold system it uses the same mechanism as for SQL 8. When it is dropped though, instead of all the pages being deallocated completely, one IAM page & one data page are left allocated, then the temp table is put into a special cache. Subsequent temp table creations will look in the cache to see if they can just grab a pre- created temp table. If so, this avoids accessing the allocation bitmaps completely. The temp table cache isn't huge (3. SQL 7 – SP3. Helpful in case when DBCC SHRINKFILE and SHRINKDATABASE commands may not work because of sparsely populated text, ntext, or image columns. Prints detailed lock information as every request for a lock is made (the process ID and type of lock requested). Scope: global. More detailed information about the command being executed at the time of a deadlock. Documented in SQL 7 BOL. The SQL Server Database Engine will not escalate row or page locks to table locks. This can slow the performance of the Database Engine, or cause 1. For more information, see Lock Escalation (Database Engine). However, because trace flag 1. This helps avoid . Scope: global or session. SQL 7 - Disables Health reporting. Lock monitor when detects a (worker thread) resource level blocking scenario. If a SPID that owns a lock is currently queued to the scheduler, because all the assigned worker threads have been created and all the assigned worker threads are in an un- resolvable wait state, the following error message is written to the SQL Server error log. Error 1. 22. 3: Process ID %d: %d cannot acquire lock . Process ID %d: % d holds a lock . Scope: global. Disables lock escalation based on the number of locks. However, memory pressure can still activate lock escalation (when > 4. The Database Engine escalates row or page locks to table (or partition) locks if the amount of memory used by lock objects exceeds one of the following conditions. Db Engine, exclusive of memory allocation using AWE. This is applicable when the locks parameter of sp. However, because trace flag 1. Lock monitor when detects a (worker thread) resource level blocking scenario. If a SPID that owns a lock is currently queued to the scheduler, because all the assigned worker threads have been created and all the assigned worker threads are in an un- resolvable wait state, the following error message is written to the SQL Server error log: Error 1. Process ID %d: %d owns resources that are blocking processes on scheduler %d. Scope: startup. SQL 9/1. When the principal database is running exposed or is isolated the Log Reader Agent will waits for log records to harden on the mirror before replicating them to the Distributor. When publisher is started with trace flag 1. Log Reader Agent can continue replicating changes regardless of the mirroring state. Scope – GLOBAL. KB 9. When you use SNAC to connect to an instance of a principal server in a database mirroring session: . KB 9. 36. 17. 9. SQL 1. Turns off log stream compression and effectively reverts the behavior back to ver 9. Used only when applications depend on the old behavior. Scope: STARTUP – KB 9. Disables instant file initialization. Not required with SQL 2. R2. KB 9. 11. 67. Makes your optimizer work harder by enabling advanced optimizations that are specific to decision support queries, applies to processing of large data sets. Using 2. 33. 5 as a startup parameter will cause SQL Server to generate a plan that is more conservative in terms of memory consumption when executing the query. It does not limit how much memory SQL Server can use. The memory configured for SQL Server will still be used by data cache, query execution & other consumers. Setup cost for the sort operation may outweigh its benefits thus resulting in poor performance. KB 2. 00. 91. 60. SQL 1. 0. 5 SP1 – Before this automatic statistics were triggered when a column would get modifications exceeding 2. On enabling this flag the standard 2. Statistics object that belong to an ascending column is branded as “ascending” after three updates on the statistics. It’s necessary to update it with ascending column values so that when the third update occurs, SQL Server brands the statistics object as ascending.
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