UxOra - Unix and Oracle tech notes
Welcome to UxOra,
This website publishes technical notes on Unix and Oracle (=UxOra) especially as a DBA point of view.
Please read the writing conventions here first.
I hope it may help you.
Michel V.
Shell script template
- Details
- Written by Michel VONGVILAY
- Category: Shell Script
It's sometimes painful to create a shell script from scratch ...
So here is a script template that can help to start any good shell script.
This template contains header which is use for usage info as well, useful predefined functions and predefined variables, and manage short and long options.
(template.sh zip file is attached in this article)
VirtualBox Guest Additions on Oracle Linux 7
- Details
- Written by Michel VONGVILAY
- Category: Admin
After installing Oracle Enterprise Linux 7 (OEL7) virtual machine on VirtualBox (as explained here), I would recommend to install the VirtualBox Guest Additions.
For any serious and interactive use, the VirtualBox Guest Additions will make your life much easier by providing closer integration between host and guest and improving the interactive performance of guest systems.
Virtualbox
Install Oracle Linux 7 on VirtualBox
- Details
- Written by Michel VONGVILAY
- Category: Admin
This article will show step by step how to configure a virtual machine on VirtualBox in order to install Oracle Enterprise Linux 7 (OEL7).
Before going through those steps, you will need to have:
- Oracle VM VirtualBox installed, it can be downloaded from virtualbox.org
- OEL7 (V46135-01) iso image, it can be downloaded from edelivery.oracle.com with a free oracle account
(warning: images-intensive article)
Table Monitoring and Statistics
- Details
- Written by Michel VONGVILAY
- Category: DBA
Table monitoring is by default activated if STATISTICS_LEVEL
system parameter is set to TYPICAL
(or ALL
).
Oracle keeps table monitoring data in memory, then flush it into the dictionary when DBMS_STATS
. FLUSH_DATABASE_MONITORING_INFO
is called. These datas are mainly used to determine if objects need new statistics.
Incremental Statistics
- Details
- Written by Michel VONGVILAY
- Category: DBA
When DBMS_STATS.GATHER_TABLE_STATS
collects statistics on a partitioned table, generally it does so at the partition and table (global) level (the default behavior can be modified by changing the GRANULARITY
parameter). This is done in two steps:
- First, partition level stats are gathered by scanning the partition(s) that have stale or empty stats,
- Then a full table scan is executed to gather the global statistics.
As more partitions are added to a given table, the longer the execution time for GATHER_TABLE_STATS
, due to the full table scan requited for global stats.