Works by storing the plan. Cardinality is not the primary factor. Provides additional data to Optimizer. Helps Optimizer
Non-database developers doing database coding ... Nested Loop to Hash Join. Preventing Bad SQLs in the Cloud. 9 ... Code
queries and approve them. DBA. Developer. Manager. 3. Preventing Bad SQLs in the Cloud. 4. We have been running this SQL
demographic factors, symptomatology and tardive dyskine- sia. Acta Psychiatr Scand 1996;/94:/118Ð24. [23] Kusel Y, Laugharne R, Perrington S, McKendrick J,.
changes in their clients after the treatment in their studies. .... have mood swings. 0.61. 0.39 .... [4] Wilkinson G, Hesdon B, Wild D, Cookson R, Farina C,. Sharma ...
and health data) leakage and loss of privacy in the cloud ... Yahoo, and Salesforce [15]. Also ... cloud computing market, but they represent only a small ..... archives, text files and PDF files. .... http://java.sun.com/docs/books/tutorial/deployme
Aug 28, 2009 - Preventing Bad Plans by Bounding the. Impact of Cardinality Estimation Errors. Guido Moerkotte. University of Mannheim. Mannheim, Germany.
Cloud is a distributed network of storage systems storing data reliably over a very long period of time. Security is essential in cloud because cloud is a multi-.
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Aug 8, 2017 - best security software money can buy, with equally developed ... how to secure multi-tenancy for the cloud
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new drugs whose profile of unwanted effects has not been fully defined ... 8 Chouinard G, Jones B, Remington G, Bloom D, Addington D, MacEwan GW, et al.
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services spending reached $47.4 billion in 2013 and will.
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Requires development skills. â Not typical DBA skills ... Not in the loop for application deployment. ⢠Code can't b
Preventing Bad SQLs in the Cloud Arup Nanda Longtime DBA
Preventing Bad SQLs in the Cloud
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DBA Developer should have taken care of this.
Developer Why isn’t the DBA aware of this problem?
Manager DBA will review all queries and approve them.
Preventing Bad SQLs in the Cloud
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We have been running this SQL for ages. Never had a problem. Until Now. Preventing Bad SQLs in the Cloud
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Why Good SQLs Go Bad … • Missing, Incomplete or Inaccurate Statistics • Improper or Lack of Indexing • Bad Syntax – WHERE COL1+20 = COL2 – WHERE UPPER(COL1) = ‘XYZ’
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Why Good SQLs Go Bad • High Demand for Data Buffers • Bind peeking • Upgrades, patches.
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Solutions … • Adding or Correcting Indexing – Index Absent – Proper Index- B-tree? Bitmap? Unique?
• Rewriting the SQL – e.g. col1+10=:v1 becomes col1=:v1-10 – Nested Loop to Hash Join Preventing Bad SQLs in the Cloud
• Collect Accurate Statistics • Put Hints • Create Outlines. Preventing Bad SQLs in the Cloud
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Challenges … • Tough to determine why plans go bad, at least quickly • Requires development skills – Not typical DBA skills
• Volume of statements to tune • Time – Almost always reactive – Do it now. Under pressure! Preventing Bad SQLs in the Cloud
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Challenges • Not in the loop for application deployment • Code can’t be changed, i.e. no hints • Lack of Testing – Time – Resources. Preventing Bad SQLs in the Cloud
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Added Challenge in Cloud • Shared Infrastructure – Resource Manager
• DevOps: Continuous Deployment – A moving target
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SQL Profile Hints are automatically added to queries Gives more information about the accessed objects, data, etc. Different from SQL Plan Management Baselines Preventing Bad SQLs in the Cloud
