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Compare statistics, good idea, Ok, here is the scenario You have a large table where you have collected the statistics with sample of 10%, and due to some reasons you want to collect the statistics with auto or 100% sample size, but you are unsure of the difference it make. Note its not about to […] Symptoms: Alert log says WAITED TOO LONG FOR A ROW CACHE ENQUEUE LOCK! Wait events in Node A: DFS Lock Handle and hanged Wait events in Node B: row cache locks and library cache locks (sessions permitted but very slow) AWR reports says for the interesting period: DFS Lock Handle Background:- DFS Lock […] Adaptive cursor sharing introduced in 11g R1 to address the bind peeking issues with things track especially the bind aware and bind sensitivity. This is for plan stability right, Read here more on this. Can this stability when bind peeking issues is be achievable in 10g, well the obvious answer is sql profiles, stored out […] Adaptive cursor sharing as you all aware , This was introduced in 11gR1 to address issues related to bind variable peeking. See support note 740052.1 and documentation for details. You may have weird behaviors of your sql’s after upgrade to 11g , this may be due to no proper testing done, or optimizer features […] The following is the direct extract from the documentation on adaptive cursor sharing. The adaptive cursor sharing feature enables a single statement that contains bind variables to use multiple execution plans. Cursor sharing is "adaptive" because the cursor adapts its behavior so that the database does not always use the same plan for […] Getting this error, RMAN-00571: ====================================================== RMAN-00569: ========= ERROR MESSAGE STACK FOLLOWS =============== RMAN-00571: ===================================================== RMAN-03009: failure of backup command on ch02 channel at 10/08/2012 18:18:35 ORA-19566: exceeded limit of 0 corrupt blocks for file /testdb/dev/oradata/test13.dbf Get the file id of the above file using select file_id from dba_data_files where file_name=’/testdb/dev/oradata/test13.dbf’; File_id —— […] Original and New Implementation for Nested Loop Joins Oracle Database 11g Release 1 (11.1) introduces a new implementation for nested loop joins. As a result, execution plans that include nested loops might appear different than they did in previous releases of Oracle Database. Both the new implementation and the original implementation for nested loop joins […] Series: Part 1, Part 2, Part3 Typical Oracle physical corruptions may pose are, (a) ORA-01578 – This error explains physical structural damage with a particular block. (b) ORA-08103 – This error is a logical corruption error for a particular data block. (c) ORA-00600 [2662] – This error is related to block corruption , and occurs […] Series: Part 1, Part 2, Part3 Oracle will have two types of corruptions , Physical & Logical corruptions. Physical Block Corruptions This kind of block corruptions are normally reported by Oracle with error ORA-1578 and the detailed corruption description is printed in the alert log. Corruption Examples are: Bad header – the beginning of the […] |
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Oracle 23c New Features for DBA's
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