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blog.tanelpoder.com | ||
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www.dbaglobe.com
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| | | | | A blog about on new technologie. Hands-on note about Hadoop, Cloudera, Hortonworks, NoSQL, Cassandra, Neo4j, MongoDB, Oracle, SQL Server, Linux, etc. | |
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tanelpoder.com
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| | | | | On Exadata (or when setting cell_offload_plan_display = always on non-Exadata) you may see the storage() predicate in addition to the usual access() and filter() predicates in an execution plan: SQL> SELECT * FROM dual WHERE dummy = 'X'; D - X Check the plan: SQL> @x Display execution plan for last statement for this session from library cache... PLAN_TABLE_OUTPUT ------------------------------------------------------------------------------------------------------------------------ SQL_ID dtjs9v7q7zj1g, child number 0 ------------------------------------- SELECT * FROM dual WHERE dummy = 'X' Plan hash value: 272002086 ------------------------------------------------------------------------ | Id | Operation | Name | E-Rows |E-Bytes| Cost (%CPU)| ------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | | | 2 (100)| |* 1 | TABLE ACCESS STORAGE FULL| DUAL | 1 | 2 | 2 (0)| ------------------------------------------------------------------------ Predicate Information (identified by operation id): --------------------------------------------------- 1 - storage("DUMMY"='X') filter("DUMMY"='X') The access() and filter() predicates come from the corresponding ACCESS_PREDICATES and FILTER_PREDICATES columns in V$SQL_PLAN. But there's no STORAGE_PREDICATES column there! - Linux, Oracle, SQL performance tuning and troubleshooting - consulting & training. | |
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hourim.wordpress.com
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| | | | | The last Jonathan Lewis post on RAC Planswhich finished by the following phrases: "If you're going to hard-code hints into a query then take a look at the outline it generates when it does the right thing, and that will tell you about the 15 or so hints you've missed out. (Better still, consider generating... | |
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dioncho.wordpress.com
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| | | One of my colleagues sent following test case, of which he couldn't control the join order with hints. 1. Create objects - table t1, t2 and t3 2. Now Let's set the join order as T1->T2->T3, using global hints convention. But it seems that Oracle does not work as expected. It really seems that the... | ||