With the announcement of Oracle GoldenGate 12c (220.127.116.11.0) at Oracle Open World this year, I was interested in hearing that Oracle has finally integrated the heartbeat process into the core functionality of GoldenGate. Setting up the heartbeat is always a fun thing to do with GoldenGate and I had hoped that this move to integrated it would bring benefits with it. To my dismay, I’m a little underwhelmed with the heartbeat (more...)
Oracle 12c introduced a new capability to move a partition online, without any interruptions to DML happening at the same time. But, there’s a catch. So far we’ve been able to use basic table compression without having to worry about any extra licensing – it was just a plain EE feature.
If you are planning to use the online partition move functionality, carefully check if you’re not using basic compression anywhere. For example:
I’ve often found that while I’m investigating one Oracle feature I get waylaid by noticing anomalies in other parts of the code. I was caught by one of these events a little while ago while experimenting with the new (18.104.22.168) Inmemory Columnar Store. After reading a posting by Martin Bach I asked the question:
“If you have a partitioned table with a local index and one of the table partitions has (more...)
display information about database feature usage statistics.That's all I can find in The (12.1) Docu.
Just in case anyone asks - DBA_FEATURE_USAGE_STATISTICS is not mentioned in the license guide at all:
Still for me it's interesting what's behind the view, and how it's content is populated.
So I started to analyze it's anatomy.
Starting with the view definition (slightly rewritten for better readability):
For one of my clients, I experienced several issues with applying PSU 22.214.171.124.5 with opatch 126.96.36.199.9.
There were some code changes in opatchauto, which are not yet production-ready. I am looking forward to seeing a new opatch release (maybe 188.8.131.52 or 11) which has these issues fixed.
Bug 22091017 : OPATCHAUTO -ANALYZE COMMAND SHUTS DOWN THE RDBMS HOME IN 12C
“opatchauto apply -analyze” is (more...)
Yesterday I gave my yearly presentation “Best of Oracle Security 2015” at the DOAG 2015 conference in Nürnberg. In this presentation I showed different Oracle exploits I found/modified released in 2015 in various sources.
One of the most interesting Oracle bugs in 2015 was CVE-2014-6577 (found by Trustwave, affecting 184.108.40.206, 220.127.116.11, 18.104.22.168, 12.1.02, fixed in April 2015 CPU). This bug can be used as helper (more...)
Plan degradations on upgrade are normal.
This one’s no different.
On further investigation, turned out application was setting optimizer_mode = first_rows somewhere.
First point about this is that first_rows really shouldn’t be used either as a hint or as an optimizer_mode.
What does FIRST_ROWS mean?
From 11g doco:
The optimizer uses a mix of costs and heuristics to find a best plan for fast delivery of the first few rows.
If any sort of (more...)
Here’s a little gem in 12c that arrived in my email a few days ago: a query where the result depends on the SQL*Plus arraysize!
The email had a short description, and a script to create a small data set that would demonstrate the problem. I’m not going to show you the query, or the result set, but here’s a sample of the output from an SQL*Plus session after creating the data. This is, by (more...)
Below is a SQL statement from a performance problem I was looking at the other day.
This is a real-world bit of SQL which has slightly simplified and sanitised but, I hope, without losing the real-worldliness of it and the points driving this article.
You don’t really need to be familiar with the data or table structures (I wasn’t) as this is a commentary on SQL structure and why sometimes a rewrite is the best (more...)
With the announcement of Oracle GoldenGate Studio at OOW this year, there has been a good bit of interest in what is can do for any Oracle GoldenGate environment. The basics of this new design tool is that it will allow the end user to quickly build out GoldenGate architectures and mappings; however, before you can build the architectures and mappings there needs to be a repository to store this information.
The Oracle GoldenGate Studio (more...)
- A more/better responsive design
- a WYSIWYG editor with preview mode
- Embedded content UI for ECM functionality
- New Portal REST API
- Out of the box bootstrap themes
- A Portal Jump Start kit
- Cloud Certification (on JCS)
However, there is also (more...)
The Oracle ASMFD (Filter Driver) was introduced in Oracle Database 22.214.171.124 and as of the moment it is available on Linux systems only.
Oracle ASM Filter Driver is a kernel module very much like the ASMLIB that resides in the I/O path of the Oracle ASM disks. It provides an interface between the Oracle binaries and the underlying operating environment.
Here are some of the features of ASMFD:
- Reject non-Oracle I/O
ORA-65040: operation not allowed from within a pluggable database
This error could occur if a tablespace is being dropped from within PDB and this tablespace is a former default tablespace having some of the system objects. Even system objects cannot be moved with simple alter statements from within PDBs.
So in order to move these objects from within (more...)
It is well-known that AWR, and Statspack before, take snapshots of V$ views (or rather the underlying objects) to produce the data in AWR.
It is also well-known that, when considering sql and its statistics in the shared pool, if something big hitting happens but the big-hitter is no longer in the shared pool by the time of the snapshot, then it can’t be recorded in your AWR picture of activity.
But like many things (more...)
When you create Grid Infrastructure in 126.96.36.199, you are presented with a new (annoyingly named) “-MGMTDB”
This database is a standard, 12C CDB/PDB storing transient performance and other information. If it is lost, no biggie. Just re-create it (in your voting disk DG. Aside: create a new MGMTDB_DG, move your voting disk there, re-create -MGMTDB, then move your voting disk back out to the proper multiple voting volumes.)
However, Oracle Enterprise (more...)
Here’s a query which I find useful in order to have a very quick comparison across AWR snapshots of the high level time model statistics.
The numbers should match those in the associated section in the AWR report.
If you feel compulsed, obsessively, with tuning then you may see some blips here and there which then encourage you to dive into the AWR detail for that snapshot.
Or quite often I get in in the (more...)