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You are here		blog.tanelpoder.com Optimizer statistics-driven direct path read decision for full table scans (_direct_read_decision_statistics_driven) \| Tanel Poder Blog
\|	\|	dincosman.com Direct Path Read Decision in Oracle: Beyond the Optimizer - Osman's DBlog	0.6 parsecs away Travel
\|	\|	The performance issue with an SQL query was resolved by using the /+ PARALLEL(2) / hint, reducing execution time from 180-200 seconds to milliseconds. The decision to perform a direct read from disk to memory instead of reading blocks from disk was made by the database engine and is controlled by the hidden "_serial_direct_read" parameter....	0.6 parsecs away Travel
\|	\|	tanelpoder.com Manual "before" and "after" snapshot support in Snapper v4 \| Tanel Poder Blog	1.0 parsecs away Travel
\|	\|	Snapper used to require access to DBMS_LOCK, so it could sleep for X seconds between the "before" and "after" performance data snapshots. Now it is possible to get away without using DBMS_LOCK. Instead you will run Snapper twice, once for taking the "before" snapshot, then run your workload and then run Snapper again for taking the "after" snapshot and print the output. So, the usual way of running snapper is this: - Linux, Oracle, SQL performance tuning and troubleshooting training & writing.	1.0 parsecs away Travel
\|	\|	tanelpoder.com Alter session force parallel query doesn't really force anything \| Tanel Poder Blog	1.7 parsecs away Travel
\|	\|	Jonathan Lewis has already written about this behavior from the angle of PARALLEL hints. I'm writing a similar article just because the word FORCE in the ALTER SESSION FORCE PARALLEL QUERY syntax. Force should mean that some behavior would always happen (when possible), right? Let's test: SQL> CREATE TABLE t AS SELECT * FROM dba_objects; Table created. SQL> CREATE INDEX i ON t(owner); Index created. SQL> @gts t Gather Table Statistics for table t... PL/SQL procedure successfully completed. Now let's "force" the parallel query in my session, run the query and check the execution plan: - Linux, Oracle, SQL performance tuning and troubleshooting training & writing.	1.7 parsecs away Travel
\|	\|	rwijk.blogspot.com About Oracle: dbms_xplan.display_cursor	11.9 parsecs away Travel
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