Parallel Execution -- 2 PX Servers
I've posted a couple of examples (here and here) of Parallel Execution servers for Parallel Query.How do we identify usage of Parallel Execution ?I will update this post (and, possibly, subsequent...
View ArticleParallel Execution -- 2b PX Servers
Continuing my previous post, here I demonstrate using V$SQLSTATS.PX_SERVERS_EXECUTIONS and a couple of issues around it.I have restarted the database.[oracle@localhost ~]$ sqlplus...
View ArticleParallel Execution -- 2c PX Servers
Adding to my two previous posts here and here about identifying usage of Parallel Execution -- exactly how many PX servers were used for a query, here is a third method. (the first two are...
View ArticleParallel Execution -- 3 Limiting PX Servers
In my previous posts, I have demonstrated how Oracle "auto"computes the DoP when using the PARALLEL Hint by itself, even when PARALLEL_DEGREE_POLICY is set to MANUAL. This "auto"computed value is...
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1 million page views in less than 5 years
My Oracle Blog has recorded 1million page views in less than 5 years.Although the blog began on 28-Dec-2006, the first month with recorded page view counts was July-2010 -- 8,176 page views....
View ArticleParallel Execution -- 3b Limiting PX Servers with Resource Manager
As demonstrated earlier, in the absence of CALIBRATE_IO, the "automatic" degree computed by a PARALLEL Hint is CPU_COUNT x PARALLEL_THREADS_PER_CPUHEMANT>select degree from user_tables where...
View ArticleParallel Execution -- 4 Parsing PX Queries
Unlike "regular" Serial Execution queries that undergo only 1 hard parse and multiple soft parses on repeated execution, Parallel Execution queries actually are hard parsed by each PX Server plus the...
View ArticleParallel Execution -- 5 Parallel INSERT
Oracle permits Parallel DML (as with Parallel Query, this requires the Enterprise Edition).Unlike Parallel Query, Parallel DML is *not* enabled by default. You must explicitly enable it with an ALTER...
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Status Of My SlideShare Material
My SlideShare Material has had 7,390 views to date....
View ArticleParallel Execution -- 5b Parallel INSERT Execution Plan
As noted in my previous post, Oracle does NOT enable Parallel DML by default. You need to explicitly enable it with ALTER SESSION ENABLE PARALLEL DML.Can you use the Execution Plan of an INSERT...
View ArticleParallel Execution -- 6 Parallel DML Restrictions
Here's link to the 11.2 documentation on Restrictions on Parallel DMLSo, some of the implications are :1. You cannot do Parallel DML if a Trigger is present on the target table2. Certain integrity...
View ArticleRMAN -- 1 : Backup Job Details
Here's a post on how you could be misled by a simple report on the V$RMAN_BACKUP_JOB_DETAILS view.Suppose I run RMAN Backups through a shell script. Like this :[oracle@localhost Hemant]$ ls -l...
View ArticleRMAN -- 2 : ArchiveLog Deletion Policy
Most Internet references about defining the ArchiveLog Deletion Policy relate to the necessity to preserve ArchiveLogs for Standby databases.For example, the configuration here prevents deletion unless...
View ArticleRMAN - 3 : The DB_UNIQUE_NAME in Backups to the FRA
When you run RMAN Backups to the FRA without using the FORMAT clause, Oracle automatically generates filenames for the BackupPieces. The folder name is derived from the system date. But what is the...
View ArticleRMAN -- 4 : Recovering from an Incomplete Restore
What do you do if a RESTORE fails mid-way ? Do you need to rerun the whole restore ? If it is a very large database, it could take [many ?] hours.RMAN is "smart" enough to detect datafiles that have...
View ArticleRMAN -- 4b : Recovering from an Incomplete Restore with OMF Files
Following up on my previous post (which had the datafiles as non-OMF), here is a case with OMF files.SQL> select file_name from dba_data_files 2 where tablespace_name =...
View ArticleRMAN -- 5 : Useful KEYWORDs and SubClauses
I begin a subseries on useful KEYWORDs and SubClauses in the RMAN Command Set.This is on the less-commonly used KEYWORDs (Thus, I don't show CONFIGURE CONTROLFILE AUTOBACKUP ON in this post or SET...
View ArticleMonitoring and Diagnostics without Oracle Enterprise Manager
Here's a copy of a presentation I made at Singapore Oracle Sessions - III ,14-Jul-2015 on the topic of Monitoring and Diagnostics without Oracle Enterprise Manager....
View ArticleRMAN -- 5b : (More) Useful KEYWORDs and SubClauses
Here are a few more useful KEYWORDs and SubClausesSECTION SIZE SECTION SIZE allows you to split a single Database file into multiple sections. Note : A Database File span BackupPieces. The...
View ArticleRMAN -- 5c : (Some More) Useful KEYWORDs and SubClauses
Here are a few more useful KEYWORDs and SubClausesAS COPY and COPY OFUnlike the BACKUPSET format that is the default for an RMAN Backup, Image Copy backups (those that would be akin to backups...
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