Changes to the Oracle 11g Optimizer That Affect Tuning
Learn about some signiticant changes to the Oracle 11g optimzer that can affect SQL query tuning.
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What If I Create a Bad Oracle Index?
While Oracle’s cost-based optimizer generally suppresses poor indexes, problems can still develop when a bad index is used at the same time as a good index. Learn why.
Read MoreWhen Should I Use an Oracle Index?
Choosing to use an index in Oracle depends on how the data and indexes are architected, how the data is distributed within the blocks, and how it is accessed.
Read MoreHow is AUTOTRACE Different from EXPLAIN PLAN?
The Oracle command AUTOTRACE executes the query (in the way TRACE does) and automatically queries the plan table, and the EXPLAIN PLAN command does neither. Learn more.
Read MoreUsing the Oracle EXPLAIN PLAN Alone
The EXPLAIN PLAN command allows you to view the query execution plan and can be helpful in improving the performance of SQL statements. Learn more.
Read MoreTop 25 Oracle Initialization Parameters
See one expert’s list of the 25 most important Oracle initialization parameters, in order of importance.
Read MoreUnderstanding the Oracle Optimizer Modes
The Oracle cost-based optimizer has two modes of operation: normal mode and tuning mode. Learn when to use these modes.
Read MoreOracle Pools Used to Store the Actual Data in Memory
The initialization parameters DB_CACHE_SIZE, DB_KEEP_CACHE_SIZE, and DB_RECYCLE_CACHE_SIZE are the determining factors for memory used to store data in Oracle.
Read MoreOracle Waits and Latches Related to Initialization Parameters
Setting Oracle initialization parameters incorrectly can result in performance issues that show up as general “waits” or “latch waits” in a STATSPACK report. Learn more.
Read MoreBest Settings for Oracle Library Cache Reload and Library Cache Hit Ratios
For optimal performance, keep the Oracle library cache reload ratio at zero and the library cache hit ratio greater than 95 percent. Learn more.
Read MoreBest Settings for Oracle Data Dictionary Cache Hit Ratio
The Oracle data dictionary cache is a key area to tune because the dictionary is accessed so frequently, but it should be monitored only after the system has been up for a while and stabilized.
Read MoreOptimal Use of the Shared SQL Area in Oracle
To ensure optimal use of the shared SQL area in Oracle, use stored procedures as much as possible. Learn more.
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