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Showing posts with label EXPLAIN. Show all posts
Showing posts with label EXPLAIN. Show all posts
Saturday, 24 August 2013

Db2 Sort Pool and DSNDB07: Work Files, Sort Spills, and Tuning Checks

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Sorts spill to DSNDB07 when memory is not enough.  A query with ORDER BY , GROUP BY , DISTINCT , or a join that cannot...
Saturday, 17 August 2013

Db2 Indexing Guide: B-Tree, Composite, Clustering, and Index-Only Access

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 Index design starts with real WHERE clauses. An index can turn a four-hour customer lookup step into a few minutes, ...

Db2 Optimizer Guide: RUNSTATS, EXPLAIN, Indexes, and Access Paths

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 Optimizer choices depend on SQL, statistics, and indexes. A batch job can read ten rows or ten million rows from the...
Saturday, 10 August 2013

Db2 SQL Optimization Tips for COBOL Programs

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 Db2 SQL tuning starts with access-path evidence. A batch job named ACCTPOST can look healthy in test and still burn...
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