RMAN -- 6 : RETENTION POLICY and CONTROL_FILE_RECORD_KEEP_TIME
Most people read the documentation on CONTROL_FILE_RECORD_KEEP_TIME and believe that this parameter *guarantees* that Oracle will retain backup records for that long. (Some do understand that backup...
View ArticleRMAN -- 7 : Recovery Through RESETLOGS -- how are the ArchiveLogs identified ?
When Oracle introduced "official" support for Recovery through RESETLOGS in 10g, it introduced the "%r" component of the log_archive_format parameter. (This was not present in 9.2)Therefore, in 10.2,...
View ArticleRMAN -- 8 : Using a Recovery Catalog Schema
Besides retaining information about backups in the controlfile, Oracle allows the use of an (external) Recovery Catalog schema. This schema is queryable via SQL in the same manner as querying any user...
View ArticleRMAN -- 9 : Querying the RMAN Views / Catalog
The "data dictionary" for RMAN is in (a) V$ views from the controlfile and, if a Catalog Schema is implemented (b) Catalog Views.A useful mapping of the two sets is(for 11.2) at...
View ArticleRMAN -- 10 : VALIDATE
There are two different VALIDATE commands for Backups. (These are different from RESTORE VALIDATE which I'd blogged about earlier in 10.2 here)The first is BACKUP VALIDATE which is useful to...
View ArticleMy YouTube Videos as introductions to Oracle SQL and DBA
From my teaching an 11g OCA program, I've developed (and will continue to add) a few videos for those who are just beginning with Oracle SQL and DBA and/or those intending to prepare for the SQL or 11g...
View ArticleTrace Files -- 1 : Generating SQL Traces (own session)
Beginning a new series of posts on Trace Files.An SQL Trace captures SQL statements (including recursive SQL calls -- e.g. data dictionary lookups or triggers being executed, which are not "directly"...
View ArticleTrace Files -- 2 : Generating SQL Traces (another session)
Here are a few methods to trace another session to capture SQL statement executions. All of these methods require the appropriate privilege --- which most DBAs seem to mean using SYS (which logs in AS...
View ArticleTrace Files -- 3 : Tracing for specific SQLs
11g allows definition of tracing by SQL_ID as well.Here is an example.Given a particular SQL that has been executed in the past, which we've identified as :SQL> select sql_id, sql_text, executions...
View ArticleTrace Files -- 4 : Identifying a Trace File
This post updated on 21-Oct-15 to show retrieval of the tracefile name from v$processThe server processid 2992 was on 18-Oct. The 21-Oct server processid was 3079.11g has a V$SQL_DIAG that one can use...
View ArticleTrace Files -- 5.1 : Reading an SQL Trace
Here's a short introduction to reading an SQL Trace.First I execute these in my sqlplus session :SQL> connect hr/oracleConnected.SQL> exec...
View ArticleTrace Files -- 5.2 : Interpreting the SQL Trace Summary level
Picking up the same SQL Trace file from my previous post, I run (the well known) utility tkprof on it.[oracle@ora11204 Desktop]$ tkprof /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_3039.trc...
View ArticleTrace Files -- 6 : Multiple Executions of the same SQL
In the previous two posts, I demonstrated a single execution of an SQL query and interpreting the raw trace and the tkprof summary for it. The demonstration also showed the Hard Parsing for the first...
View ArticleSSL Support
This blog now supports SSL connections.Browse this blog using https:// instead of http:// for a secure connection when accessing a specific page....
View ArticleTrace Files -- 7 : SQL in PL/SQL
So far, all my examples of Tracing have been 'pure' SQL. What does a Trace File show for SQL that is executed from within PL/SQL ?I run this code where I trace only the execution of the stored...
View ArticleTrace Files -- 8a : Using SQL Trace for Performance Evaluations
All previous examples of tracing are only to demonstrate enabling tracing and viewing the results.Now, I present a case where we can use tracing to evaluate performance of queries. There may be a...
View ArticleTrace Files -- 8b : More Performance Evaluation from Trace File
Continuing with the same table as in the previous example, but with the addition of(a) Statistics on the table(b) An Index on the CREATED columnSQL> select count(*) from all_objects_many_list;...
View ArticleTrace Files -- 8c : Still More Performance Evaluation from Trace File
In previous blog posts here and here, I have demonstrated Full Table Scans of a table called ALL_OBJECTS_MANY_LIST being executed via Direct Path Reads (shown as 'direct path read') in the Wait...
View ArticleAuditing DBMS_STATS usage
(I will be returning to the Tracing series .... but a quick diversion because I had received a request for assistance on auditing DBMS_STATS usage)First, I setup auditingSQL> alter system set...
View ArticleTrace Files -- 8d : Full Table Scans
In the previous two posts, I have demonstrated direct path read and db file scattered read being used for Full Table Scans. Since 11g, Oracle uses an internal formula to determine the manner of...
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