I was testing Oracle Goldengate on a non-clustered Oracle 188.8.131.52 database with ASM. With ASM, you need to have the grid infrastructure installed. The cluster ware for the single node install is called ‘oracle restart’.
The most convenient way to have Goldengate running at startup that I could find, was using the Oracle Grid Infrastructure Agents. These agents are not installed by default, you need to download these from the Oracle Technology Network. The download is with the grid infrastructure downloads in the database section.
The installation is very simple: unzip the xagpack_6.zip file, and run the xagsetup.sh script with the arguments ‘–install’ and ‘–directory’ arguments. The directory argument needs to point to a directory outside of the grid infrastructure home. My first choice would be to have it in the infrastructure home, but the install script does not allow that.
I’ve updated some of my ASH scripts to use these 4 arguments in a standard way:
Here’s a quirky little bug that appeared on the OTN database forum in the last 24 hours which (in 12c, at least) produces an issue which I can best demonstrate with the following cut-n-paste:
There was a little conversation on Oracle-L about ASH (active session history) recently which I thought worth highlighting – partly because it raised a detail that I had got wrong until Tim Gorman corrected me a few years ago.
Once every second the dynamic performance view v$active_session_history copies information about active sessions from v$session. (There are a couple of exceptions to the this rule – for example if a session has called dbms_lock.sleep() it will appear in v$session as state = ‘ACTIVE’, but it will not be recorded in v$active_session_history.) Each of these snapshots is referred to as a “sample” and may hold zero, one, or many rows.
Some time ago I wrote a blog note describing a hack for refreshing a large materialized view with minimum overhead by taking advantage of a single-partition partitioned table. This note describes how Oracle 12c now gives you an official way of doing something similar – the “out of place” refresh.
I’ll start by creating a matieralized view and creating a couple of indexes on the resulting underlying table; then show you three different calls to refresh the view. The materialized view is based on all_objects so it can’t be made available for query rewrite (ORA-30354: Query rewrite not allowed on SYS relations) , and I haven’t created any materialized view logs so there’s no question of fast refreshes – but all I intend to do here is show you the relative impact of a complete refresh.
Here are the slides of a presentation I did at the IOUG Virtual Exadata conference in February. I’m explaining the basics of some new Oracle 12c things related to Exadata, plus current latest cellsrv improvements like Columnar Flash Cache and IO skipping for Min/Max retrieval using Storage Indexes:
Note that Christian Antognini and Roger MacNicol have written separate articles about some new features:
This article is written with examples taken from an (virtualised) Oracle Linux 6u6 X86_64 operating system, and Oracle database version 184.108.40.206.1. However, I think the same behaviour is true for Oracle 11 and 10 and earlier versions.
Probably most readers of this blog are aware that a “map” of mapped memory for a process exists for every process in /proc, in a pseudo file called “maps”. If I want to look at my current process’ mappings, I can simply issue:
Yeah, so I did it- I installed SQLTXPLAIN, (SQLT) on the AWR Warehouse!
One of the waits that is specific to ASSM (automatic segment space management) is the “enq: FB – contention” wait. You find that the “FB” enqueue has the following description and wait information when you query v$lock_type, and v$event_name: