ORA-16534 When Converting to/from Snapshot Standby with DataGuard Broker

We here at Seilerwerks Industries (not really) have been using snapshot standby databases to refresh an array of unit test databases from a common primary. During the business day, these would be converted to snapshot standby databases for testing, then overnight they are converted back to physical standby and recovered up to the master again.

However we ran into one problem the other week. I noticed that the test3 database was still in physical standby (more...)

Reminder: first Arizona Oracle User Group meeting tomorrow

Fellow Phoenicians (citizens of the Phoenix, Arizona area):

This is a reminder that tomorrow is the first meeting of the newly reborn (risen from the ashes) Arizona Oracle User Group.  Here are the meeting details: url

I hope to meet some of my fellow Phoenix area DBAs tomorrow afternoon.

– Bobby


OCP 12C – DataPump, SQL*Loader, External Tables Enhancements

Oracle DataPump Enhancements Full Transportable Export and Import of Data In Oracle 12c you now have the possibility to create full transportable exports and imports. A full transportable export contains all objects and data needed to create a copy of the database. To create a fully transportable export of your database you need to specify [...]

The post OCP 12C – DataPump, SQL*Loader, External Tables Enhancements appeared first on Oracle DBA Scripts and Articles (more...)


A recent question on the OTN forum asked about narrowing down the cause of deadlocks, and this prompted me to set up a little example. Here’s a deadlock graph of a not-quite-standard type:

Deadlock graph:
                                          ---------Blocker(s)--------  ---------Waiter(s)---------
Resource Name                             process session holds waits  process session holds waits
TX-00040001-000008EC-00000000-00000000         50     249     X             48       9           X
TX-000A001F-000008BC-00000000-00000000         48       9     X             50     249           S

My session (the one that dumped the trace file) is 249, and I was blocked (more...)

Memory Improvement

Oracle 12c (version offers the option of using in-memory processing to speed things along. Called the In-memory option it’s installed when you install the software. Using it can make a considerable difference in processing speed, provided you have sufficient resources (RAM) available. Let’s revisit an older example, on Bloom filters, and see if Oracle processes things any faster in-memory.

Looking again at the Bloom filter example using (more...)

OCP 12C – Partitioning Enhancements

Online Partition operations Table Partitions and subpartitions can now be moved online. [crayon-5447caf7d0323514534927/] Compression options can also be added during an online partition move. [crayon-5447caf7d034e673459253/] Reference Partitioning Enhancements Truncate or Exchange Partition with Cascade option With Oracle 12c, it is now possible to use the CASCADE option to cascade operations to a child-referenced table when [...]

The post OCP 12C – Partitioning Enhancements appeared first on Oracle DBA Scripts and Articles (Montreal).

getting re certified for 12c ( makes me grumpy ) …

So let's be honest at the beginning here.

I have way too many professional certifications for any reasonable semi honest human being.  Along with two old Solaris admin certifications 7 and 8 I am ( besides an MBA degree ha ha ) OCP in 7.3 / 8.0 / 8i / 9i / 10g.  At one point a ways back I was teaching all the OCP curriculum for a local community college (more...)

Script to compare plan performance

Here’s a zip of a script I modified today: zip

Here’s an example output:

---------- ------------- --------------- ---------- ----------- -------------- ----------- ---------- -------------- --------------- ---------- ---------- ---------- ----------------- -------------- ---------------
         1 gxk0cj3qxug85      2051250004   39504258  31630.2852             15  4.71993394 .444248288     4.07294381      440.124393 41.3960784 3447.83137 28056.5262                 0     .006406626               0
         1 gxk0cj3qxug85       548353012   24360619   (more...)

SQL Mini-challenge entry: Craig Martin v4

by Craig Martin

So from my last post Brendan Furey pointed out one minor detail.. that my code was seriously flawed. It only returned the results from one of the criteria found. Picky, picky :) So this is my last effort.. Back up to 12 buffers, but still works when you change the parameters:

select /*+ ordered index_ffs(j job_id_pk) use_nl(jh) use_nl(e) use_nl(e2) use_nl(e3) use_nl(d) use_nl(l) */  distinct l.location_id, l.city
from dual
    left outer  (more...)

SQL Mini-Challenge Update

The SQL Mini-Challenge is now closed. The judges will be Kyle Hailey, Tim Gorman, and Iggy Fernandez. The winner will be announced in the fall issue of the NoCOUG Journal.

Correctness is the primary screening criterion that will be used by the judges. Submissions are expected to produce the same results as the original query even if the data changes. The following script has been constructed to test submissions:

update employees

OCP 12C – Index and Table Enhancements

Table Enhancements Oracle 12c offers you to create invisible columns, these columns are not visible until you explicitly mention their names in the SQL statement. This functionnality allows developpers to make change to the database without conflicting with the existing application. To create an invisible column: [crayon-544665ad911af900442543/]  You can’t create invisible columns on : External [...]

The post OCP 12C – Index and Table Enhancements appeared first on Oracle DBA Scripts and Articles (Montreal).

How to See the Height of an Index

This example shows where to find the height of an index. I tested it on Oracle 11.2. First I deleted the index's statistics:

SQL> exec dbms_stats.delete_index_stats -
> ('uimsmgr','ubbchst_serv_index');
PL/SQL procedure successfully completed.
Then I checked its BLEVEL was null:

SQL> select nvl(blevel,999)
  2  from dba_indexes
  3  where owner = 'UIMSMGR'
  4  and index_name = 'UBBCHST_SERV_INDEX'
  5  /

OCP 12C – ADR and Network Enhancements

ADR enhancements In oracle 12c the Automatic Diagnostic Repository contains a new log directories with 2 subdirectories : DDL Debug The DDL log When you active the DDL logging in Oracle 12c using enable_ddl_logging=true, Oracle writes all DDL operations into the specific DDL log instead of writting it to the alert log. To enable DDL logging [...]

The post OCP 12C – ADR and Network Enhancements appeared first on Oracle DBA Scripts and Articles (Montreal).

OCP 12C – Emergency Monitoring, Real-Time ADDM

Emergency Monitoring Emergency monitoring is meant for extreme circumstances where it’s impossible for you to connect to the database because the database is hung. Emergency monitoring allows you to connect to the database in diagnostic mode and run a lightweight analysis to see what’s happening. You can access real-time performance data from ASH and access [...]

The post OCP 12C – Emergency Monitoring, Real-Time ADDM appeared first on Oracle DBA Scripts and Articles (Montreal).

Plan depth

A recent posting on OTN reminded me that I haven’t been poking Oracle 12c very hard to see which defects in reporting execution plans have been fixed. The last time I wrote something about the problem was about 20 minhts ago referencing; but there are still oddities and irritations that make the nice easy “first child first” algorithm fail because the “depth” calculated by Oracle doesn’t match the “level” that you would get from (more...)

Dallas Oracle Users Group Performance Meetup

I spoke at a one day DOUG meeting yesterday. It was pretty cool. Very small intimate group of about 50. The speakers were Nitin Vengurlekar, Charles Kim, Cary Millsap and myself. All are Ace Directors and either work at Viscosity or Enkitec. As a bonus, Tanel Poder showed up to weigh in on some open discussion. Anyway, I thoroughly enjoyed it. I promised the group I would post my slides and a zip file with (more...)

How to setup git as a daemon

This is a quick post on using git on a server. I use my Synology NAS as a fileserver, but also as a git repository server. The default git package for Synology enables git usage on the command line, which means via ssh, or via web-DAV. Both require a logon to do anything with the repository. That is not very handy if you want to clone and pull from the repository. Of course there are (more...)

Learning Spark Lightning-Fast Big Data Analytics by Holden Karau, Andy Konwinski, Patrick Wendell, Matei Zaharia; O’Reilly Media

Apache Spark started as a research project at UC Berkeley in the AMPLab, which focuses on big data analytics. Spark is an open source cluster computing platform designed to be fast and general-purpose for data analytics - It's both fast to run and write. Spark provides primitives for in-memory cluster computing: your job can load data into memory and query it repeatedly much quicker than with disk-based systems like Hadoop MapReduce. Users can write applications (more...)

Friday Philosophy – Is Dave Working?

Is Dave across the desk from you working at the moment? Or is he goofing off? You can’t see his screen but I reckon you can make a fair stab at what he is up to, without recourse to any sort of IT monitoring systems at all. How?

How fast is Dave typing?

If Dave is typing fast, he is almost certainly not working. He’s goofing. There are very few things you can do when (more...)


Here’s a question that appeared in my email a few days ago:


Based on the formula: “sreadtim = ioseektim + db_block_size/iotrfrspeed” sreadtim should always bigger than ioseektim.

But I just did a query on my system, find it otherwise, get confused,


SNAME                          PNAME                               PVAL1 PVAL2
------------------------------ ------------------------------ ---------- --------------------
SYSSTATS_INFO                  STATUS                                    COMPLETED
SYSSTATS_INFO                  DSTART                                    10-08-2014 10:45
SYSSTATS_INFO                  DSTOP                                     10-10-2014 10:42
SYSSTATS_INFO                  FLAGS                                   1
SYSSTATS_MAIN                  CPUSPEEDNW                     680.062427
SYSSTATS_MAIN                   (more...)