We can do expdp and impdp in PDBS without passing the password so that our existing script will work. For most of them, you’ll probably use RMAN restore or Data Guard, but datapump is always a cleaner way to migrate. I have some useful tips for you in an Oracle 11g R1 database. You can leave a response, or trackback from your own site.
I would like to apologize in advance for the long post, but I wanted to DESCRIPTION. Different ways to get the current database version. I gave up after more than a month of running queries and submitting trace file after trace file.Impdp slow 19c dmp. We still have a few 9.2.0.7 because 3rd party vendors are not ready. Response is pitiful against LMT (as much as 5 minutes) but great against the system tablespace which is still DMT (1 -2 seconds). We have been using all the defaults with disastrous results using OEM to view tablespaces and files. Is there a danger in setting ‘METHOD_OPT’ to ‘FOR ALL COLUMNS SIZE 1’ for the gathering of stats on the system tables? I am concerned that changing the default METHOD_OPT will impact stats on the system tables. However, since the auto stats gathering process also gathers stats on system tables. I would like to change the METHOD_OPT parameter to the 9i default. Oracle has gathered many histograms on this schema. The second schema is an OLTP system which performs many updates to quantity columns, only a small percentage of the other attributes change. The script we have been using did not set METHOD_OPT so we were using the 10g default. It seems like the auto stats process is not gathering good stats on these tables.
I am not sure why but when we gather stats manually on the affected tables (those performing badly during data loads). One is a warehousing schema which contains many partitioned tables. We have a couple of schemas which still perform badly. Performance was bad until we made sure all instances had good system stats. I know I am late to the table, we have just finally upgraded to 10g. Select owner, table_name, column_name, count(*)įor further details on the dbms_stats package, check the script $ORACLE_HOME/rdbms/admin/dbmsstat.sql. The following query will identify columns with (real) histograms. Then re-run the collection and see if most of your problems have gone away.Īs a quick check (before thrashing the system to death rebuilding all the statistics) you might like to see how many histograms you actually have.
#Oracle 10g upgrade code#
So, before you start trouble-shooting specific SQL statements after the upgrade, go back to your stats collection scripts and modify the code to set any default values to the actual value they would have had in 9i. Select dbms_stats.get_param('METHOD_OPT') from dual īecause of this particular change, if you didn’t specify a method_opt in your scripts under 9i you were not generating histograms under 10g you will be collecting histograms on any columns that Oracle thinks might be suitable candidates. Here’s how you can see what’s happened to the “method_opt”: Of course, it’s not easy to get a direct view of all the changes because of those calls to the function dbms_stats.get_param(), but the changes are a threat. Method_opt varchar2 default 'FOR ALL COLUMNS SIZE 1',ĭefault to_estimate_percent_type(get_param('ESTIMATE_PERCENT')),ĭefault to_degree_type(get_param('DEGREE')),ĭefault to_cascade_type(get_param('CASCADE')),ĭefault to_no_invalidate_type(get_param('NO_INVALIDATE')), Here’s the definition of the procedure to gather table stats in its Oracle 9i form:
Apart from the fact that there is an automatic job (see view dba_scheduler_jobs) created to gather stale stats every day, the code that you used to run in your own stats collection routines may be doing something completely different. The other big reason is that the dbms_stats packages keeps changing its default behaviour. The second is that there are numerous new optimisation strategies in 10g, and some of them may not be good for your particular data patterns, or your particular types of query. The first is that 10g automatically enables CPU costing, and if you weren’t using it in 9i this is likely to make a difference – often an improvement but you may be unlucky.
#Oracle 10g upgrade upgrade#
When you upgrade from 9i to 10g (or higher) you may find lots of execution plans suddenly “go wrong”.
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