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kerryosborne.oracle-guy.com | ||
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savvinov.com
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| | | | | Occasionally I encounter a situation when I need to affect a part of the plan that corresponds to a view, e.g.: Such situations are resolved using global hints. Oracle offers two ways to specify a global hint: via a query block identifier (system generated or user defined) or via view aliases. System-generated query block identifiers... | |
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leonotes.wordpress.com
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| | | | | transitive closure?Wiki?Oracle?... | |
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jonathanlewis.wordpress.com
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| | | | | Following yesterday's note on SQL Profiles, someone asked how I detect that an opt_estimate hint had been used - with specific reference to the "index_scan" option. The reason for this particular choice is that other opt_estimate hints have a highly visible impact in the 10053 trace files, but this one doesn't. Here are a few... | |
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tanelpoder.com
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| | | Reading the following article about PARALLEL hint by Jonathan Lewis made me remember a somewhat related gotcha with parallelism. Often when creating (or rebuilding) an index on a large table, doing it with PARALLEL x option makes it go faster - usually in case when your IO subsystem is not the bottleneck and you have enough spare CPU capacity to throw in. A small example below: Tanel@Sol01> create table t1 as select * from all_objects; Table created. Tanel@Sol01> create index i1 on t1(object_id); Index created. Tanel@Sol01> exec dbms_stats.gather_table_stats(user, 'T1', cascade=>true, no_invalidate=>false); PL/SQL procedure successfully completed. Ok, for whatever reason I need to rebuild my index, and for speed I do it in parallel: - Linux, Oracle, SQL perf... | ||
