Trace Flags in SQL Server from Trace Flag 1603 to Trace Flag 2470

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Trace Flags in SQL Server are used to turn ON or OFF particular behavior. TraceFlags are used for variety of purposes like Logging extended information in to SQL Server errorlog, Troubleshooting or improving SQL Server Performance, Enabling certain features or functionality, etc.

Below are the SQL Server Trace Flags from Trace Flag 1603 to Trace Flag 2470.

SQL Server Trace Flag 1603 – Use standard disk I/O which turns off asynchronous I/O.

SQL Server Trace Flag 1604 – Once enabled at start up makes SQL Server output information regarding memory allocation requests.

SQL Server Trace Flag 1609 – Turns on the unpacking and checking of RPC information in Open Data Services. Used only when applications depend on the old behavior.

SQL Server Trace Flag 1610 – Boot the SQL dataserver with TCP_NODELAY enabled.

SQL Server Trace Flag 1611 – If possible, pin shared memory — check errorlog for success/failure

SQL Server Trace Flag 1613 – Set affinity of the SQL data server engine’s onto particular CPUs — usually pins engine 0 to processor 0, engine 1 to processor 1.

SQL Server Trace Flag 1704 – Prints information when a temporary table is created or dropped.

SQL Server Trace Flag 1717 – Causes new objects being created to be system objects.

SQL Server Trace Flag 1802 – In SQL Server 2005, After detaching a database that resides on network-attached storage, you cannot reattach the SQL Server database. KB 922804

SQL Server Trace Flag 1806 – Disables instant file initialization.

SQL Server Trace Flag 1807 – In SQL Server 2005 or SQL Server 2008, Allows creating a database file on a mapped or UNC network location.

SQL Server Trace Flag 2301 – Makes your optimizer work harder by enabling advanced optimizations that are specific to decision support queries, applies to processing of large data sets.

SQL Server Trace Flag 2328 – Makes cardinality estimates upon resulting selectivity. The reasoning for this is that one or more of the constants may be statement parameters, which would change from one execution of the statement to the next.

SQL Server Trace Flag 2330 – Stops the collection of statistics for sys.db_index_usage_stats.

SQL Server Trace Flag 2335 – Amount of memory available to SQL Server affects the execution plan generated though SQL Server generates the most optimal plan based on this value, but occasionally it may generate an inefficient plan for a specific query when you configure a large value for max server memory. Using 2335 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. KB 2413549.

SQL Server Trace Flag 2340 – Query processor may introduce a sort operation for optimization, though not required where the particular plan only touches a smaller number of rows. Setup cost for the sort operation may outweigh its benefits thus resulting in poor performance. KB 2009160

SQL Server Trace Flag 2371 – Before this automatic statistics were triggered when a column would get modifications exceeding 20% of the # of rows in the table. On enabling this flag the standard 20% changes to a dynamic value if table has more than 25000 rows & reduces as the count increases.

SQL Server Trace Flag 2388 – In SQL Server 2005, Detect when the leading column of a statistics object is ascending and mark or brand it as ascending. 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. Flag 2388 helps to check the statistics’ brand, when turned on the result of the DBCC SHOW_STATISTICS, has an additional column called Leading column type with the brand of the column

SQL Server Trace Flag 2389 – Tracks nature of columns by subsequent statistics updates. When SQL Server determines that the statistics increase three times, the column is branded ascending. The statistics will be updated automatically at query compile.

SQL Server Trace Flag 2390 – Does the same like 2389 even if ascending nature of the column is not known and never enable without 2389.

SQL Server Trace Flag 2440 – In SQL Server 2008, Parallel query execution strategy on partitioned tables. SQL 9 used single thread per partition parallel query execution strategy. In SQL 10, multiple threads can be allocated to a single partition by turning on this flag.

SQL Server Trace Flag 2470 – Slow performance when an AFTER trigger runs on a partitioned table in SQL Server 2008 R2 or in SQL Server 2012. KB 2606883

This is applicable on below versions of SQL Server

SQL Server 2005
SQL Server 2008 R2
SQL Server 2012
SQL Server 2014

Hope this was helpful.

Thanks,
SQLServerF1 Team
In-Depth Blogs on SQL Server, Information about SQL Server Conferences and Events, SQL Server Frequently asked questions, SQL Server Trainings.

 

Trace Flags in SQL Server from Trace Flag 902 to Trace Flag 1462

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Trace Flags in SQL Server are used to turn ON or OFF particular behavior. TraceFlags are used for variety of purposes like Logging extended information in to SQL Server errorlog, Troubleshooting or improving SQL Server Performance, Enabling certain features or functionality, etc.

Below are the SQL Server Trace Flags from Trace Flag 902 to Trace Flag 1462

SQL Server Trace Flag 902 – SQL server may not start after install or uninstall of service pack or Cumulative Update patches. Trace Flag 902 can be used to start SQL Server by skippling applying the upgrade scripts.

SQL Server Trace Flag 1106 – In SQL Server 2005, Used space in tempdb increases continuously when you run a query that creates internal objects in tempdb. KB 947204

SQL Server Trace Flag 1117 – Even growth of all files in a file group. Grows all data files at once, else it goes in turns.

SQL Server Trace Flag 1118 – Switches allocations in tempDB from 1pg at a time (for first 8 pages) to one extent. 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 (32 tables), but this can still lead to a big drop in latch contention in tempdb.

SQL Server Trace Flag 1119 – Turns off mixed extent allocation.

SQL Server Trace Flag 1140 – Continuous tempdb growth after upgrading SQL 2005 pre-SP2 to SP3/SP4 or to SQL 2008 or newer. KB 2000471.

SQL Server Trace Flag 1200 – Prints detailed lock information as every request for a lock is made and consists of the process ID and type of lock requested.

SQL Server Trace Flag 1202 – Insert blocked lock requests into syslocks.

SQL Server Trace Flag 1204 – Returns resources and types of locks participating in a deadlock and command affected.

SQL Server Trace Flag 1205 – Prints information about each deadlock search

SQL Server Trace Flag 1206 – Used to complement flag 1204 by displaying other locks held by deadlock parties.

SQL Server Trace Flag 1211 – Disables lock escalation based on memory pressure, or based on number of locks. The SQL Server Database Engine will not escalate row or page locks to table locks. Using this trace flag can generate excessive numbers of locks. This can slow the performance of the Database Engine, or cause 1204 errors (unable to allocate lock resource) because of insufficient memory.
If both trace flag 1211 and 1224 are set, 1211 takes precedence over 1224. However, because trace flag 1211 prevents escalation in every case, even under memory pressure, we recommend that you use 1224. This helps avoid “out-of-locks” errors when many locks are being used.

SQL Server Trace Flag 1222 – Returns the resources & types of locks that are participating in a deadlock and also the current command affected, in an XML format that does not comply with any XSD schema.

SQL Server Trace Flag 1224 – Disables lock escalation based on the number of locks. However, memory pressure can still activate lock escalation (when > 40%). 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:
40% of the memory that is used by Db Engine, exclusive of memory allocation using AWE. This is applicable when the locks parameter of sp_configure is set to 0.
Forty percent of the lock memory that is configured by using the locks parameter of sp_configure.

If both trace flag 1211 & 1224 are set, 1211 takes precedence. However, because trace flag 1211 prevents escalation in every case, even under memory pressure, it’s recommend to use 1224 which helps avoid “out-of-locks” errors when many locks are being used.

SQL Server Trace Flag 1260 – Disabled mini-dump for non-yield conditions.

SQL Server Trace Flag 1262 – Dump everytime a non-yielding scheduler condition is detected.

SQL Server Trace Flag 1400 – In SQL Server 2005 RTM, Enables creation of database mirroring endpoint, which is required for setting up and using database mirroring.

SQL Server Trace Flag 1439 – Trace database restart and failover messages to SQL Errorlog for mirrored databases

SQL Server Trace Flag 1448 – Prevent replication latency with database mirroring enabled. 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 1448, the Log Reader Agent can continue replicating changes regardless of the mirroring state.

SQL Server Trace Flag 1449 – When you use SNAC to connect to an instance of a principal server in a database mirroring session: “The connection attempted to fail over to a server that does not have a failover partner”. KB 936179

SQL Server Trace Flag 1462 – In SQL Server 2008, Turns off log stream compression and effectively reverts the behavior back to version 2005.

This is applicable on below versions of SQL Server

SQL Server 2005
SQL Server 2008 R2
SQL Server 2012
SQL Server 2014

Hope this was helpful.

Thanks,
SQLServerF1 Team
In-Depth Blogs on SQL Server, Information about SQL Server Conferences and Events, SQL Server Frequently asked questions, SQL Server Trainings.