Apache Drill Setup and Usuage: Install and Configure Apache Drill http://drill.apache.org/docs/installing-drill-on-windows/ sqlline> !connect “jdbc:drill:zk=local” Enter username for jdbc:drill:zk=local: admin Enter password for jdbc:drill:zk=local: ***** http://localhost:8047/ SELECT derivedtable.ItemID ,AVG( CAST (derivedtable.TimeSpent AS INTEGER)) AvgTimeSpent FROM ( SELECT rawresponsetime.Time10.`id` ItemID ,rawresponsetime.Time10.`value` `TimeSpent` FROM ( SELECT (flatten(`time`)) `Time10`, …
TempDB Contention
TempDB contention: TempDB plays very crucial in well performing SQL Server engine. These are few simple design decisions , which helps to avoid the performance bottlenecks in the long run. As a general rule, if the number of logical processors is less than or equal to …
Concurrency and Storage Needs
Concurrency and Storage Needs : Requirements: We operate on K-12 Online Summative Market. Our Needs are: When Kids log-in to take the test, they should be able to login without any issues. Should be able to store their responses and score them on the fly …
How to handle Perennial statement of “Our Database is SLOW”?
How to handle Perennial statement of “Our Database is SLOW”? I have been involved with Database and Product Development for a decade in different Verticals. I have heard this statement more than I could count “Database is Slow”,”Database is the reason”. I worked for .COM …
Snapshot Isolation in SQL Server
Snapshot Isolation in SQL Server Wiki Article on SnapShot Isolation : http://en.wikipedia.org/wiki/Snapshot_isolation Issues with SnapShot Isolation: http://sqlperformance.com/2014/06/sql-performance/the-snapshot-isolation-level Kimberly Tripp Video on Isolation Levels : http://download.microsoft.com/download/6/7/9/679B8E59-A014-4D88-9449-701493F2F9FD/HDI-ITPro-TechNet-mp4video-MCM_11_SnapshotIsolationLecture(4).m4v Kendra Little on SnapShot Isolatioin : http://www.brentozar.com/archive/2013/01/implementing-snapshot-or-read-committed-snapshot-isolation-in-sql-server-a-guide/ Microsoft Link: https://msdn.microsoft.com/en-us/library/ms188277(v=sql.105).aspx https://msdn.microsoft.com/en-us/library/bb522682.aspx SQL Team Link : http://www.sqlteam.com/article/transaction-isolation-and-the-new-snapshot-isolation-level Idera Short article on TempDB : http://sqlmag.com/site-files/sqlmag.com/files/uploads/2014/01/IderaWP_Demystifyingtempdb.pdf Jim Gray …
SQL Server Locking
Microsoft Link : https://technet.microsoft.com/en-us/library/jj856598(v=sql.110).aspx Locks held by Current Processes: SQL Server 2008 R2 https://technet.microsoft.com/en-us/library/ms189497(v=sql.105).aspx SQL Team Primer on Locks : http://www.sqlteam.com/article/introduction-to-locking-in-sql-server Kalen Delany Crisp explanation on Update Locks: http://sqlblog.com/blogs/kalen_delaney/archive/2009/11/13/update-locks.aspx UPDATE locks are not really a separate kind of lock, but rather are a hybrid of …
Random GUID or Sequential GUID
Random GUID or Sequential GUID SQL Server has two in-built functions for creating uniqueidentifier. NEWID() NEWSEQUENTIALID() New NEWSEQUENTIALID would help to reduce page splits and fragmentation because of sequential nature of the values returned from this function. NEWID() is truly (almost) random and it would …
More CPU’s in SQL Server : Does it Help or Hurt? (MAXDOP)
More CPU’s in SQL Server : Does it Help or Hurt? (MAXDOP): Common sense tells us , having more CPU’s mean more processing power , that means things would be done faster. Hold on for a sec..Its SQL Server. Common Sense isn’t applicable here. PUN …
SQL Handle and Plan Handle to Text – Quick Reference
SQL Handle to Text – Quick Reference DECLARE @pStartOffSet INT DECLARE @pEndOffSet INT DECLARE @pSQLHandle VARBINARY(64) SELECT @pSQLHandle = 0x030008001374fc0232620901c7a300000100000000000000 ,@pStartOffSet = 1788,@pEndOffSet = 3042 SELECT SUBSTRING(st.text, (@pStartOffSet/2)+1, ((CASE @pEndOffSet WHEN -1 THEN DATALENGTH(st.text) ELSE @pEndOffSet END – @pStartOffSet)/2) + 1) AS statement_text FROM sys.dm_exec_sql_text(@pSQLHandle) …
MERGE Statement and Deadlocks
MERGE Statement and Deadlocks: We have MERGE SQL Statement to satisfy our functional needs. Instead of writing separate Insert / Update (UPSERT) Statement we decided to use MERGE Statement because of its simplicity in syntax. MERGE test.Target AS t USING(SELECT ItemID, Score, TargetText FROM @SrcTable …