-
Continue reading →: Developers
Just a small Sunday night anecdote with a wider point. I, or maybe a colleague, recently received an update statement from a developer. Now, this developer is long of tooth and is well versed in the ways of Oracle data manipulation. The aforementioned update statement contained an interesting hint. BYPASS_UJVC.…
-
Continue reading →: Auditing Read-Only Standbys
For a more up-to-date post about auditing and security, read about Unified Auditing. On a read-only standby, when in Pure mode, the audit trail is written to disk (as it cannot write to a read-only database!) in a binary format which can be shipped across to the Primary occasionally and…
-
Continue reading →: Sequences – where did the view go?
I was pottering around with the sequence cache recently, investigating a few things like exactly when it refreshes (such as if it is flushed or aged from the shared pool – pin it!) and I was monitoring the next value using V$_SEQUENCE, like I have been since, erm, Oracle 8i…
-
Continue reading →: Sequences – a quick guide and an unexpected quirk
Sequences on Oracle databases are simple, but there are some basic truths about sequences which need to be understood if you are going to use them, especially on RAC: Sequences will have “holes” in them, even if you specify NOCACHE (e.g. if you rollback your transaction). Don’t specify NOCACHE. It…
-
Continue reading →: Goldengate: Problems with character sets
One complication that you may face with replicating data using Goldengate (or other tools) is when your source character set is different to your destination character set. This is particularly true when the source character set is UTF-8 and the destination is not. If the application does not sanitise (or…
-
Continue reading →: Checking the alert log – the easy way
Do you check the alert log of your databases every day? In the morning when you get in? But what about the alerts which happen during the day? How do you spot them – especially if you don’t have Grid Control or Cloud Control configured. Even if you do have a…
-
Continue reading →: UKOUG Tech 14
On Sunday I will be heading North from London to Liverpool for 4 days, to attend another UK Oracle User Group conference – #UKOUG_Tech14 I’m sure it will be as wonderful and informative a 4 days as you can get in the Oracle technical area. The hard part of attending…
-
Continue reading →: Adding a DEFAULT column in 12C
I was at a talk recently, and there was an update by Jason Arneil about adding columns to tables with DEFAULT values in Oracle 12C. The NOT NULL restriction has been lifted and now Oracle cleverly intercepts the null value and replaces it with the DEFAULT meta-data without storing it in…
-
Continue reading →: Club Oracle in London – 12th November 2014
#cluboracle free event in November 2014
-
Continue reading →: When to use the NOLOCK hint in SQL Server
I frequently hear of, and see, developers and DBA’s using the NOLOCK hint within SQL Server to bypass the locking mechanism and return their data sets as soon as possible. There are times when this is OK, such as when you are running an ad hoc query and are only…
-
Continue reading →: Extending an ACFS filesystem dynamically.
To extend an ACFS cluster filesystem dynamically, we need to use the acfsutil command: node01:/u01/grid>/sbin/acfsutil size +10G /u02 acfsutil size: ACFS-03008: The volume could not be resized. The volume expansion limit has been reached. acfsutil size: ACFS-03216: The ADVM compatibility attribute for the diskgroup was below the required version (11.2.0.4.0)…
-
Continue reading →: Grid Infrastructure Disk Space Problem – CHM DB file: crfclust.bdb
The Grid Infrastructure filesystem was reporting that it was a bit full today (release 11.2.0.4). This was tracked down to the “crfclust.bdb” file, which records information about the cluster health for monitoring purposes. It was 26GB. It’s not supposed to get bigger than 1GB so this is probably a bug,…
-
Continue reading →: Releasing to schemas the easy way
Sometimes we occasionally just miss the obvious, for years. Just noticed that an easy way to release code to a particular schema is to login as your normal DBA user (USER1) [as preferred by audit], use the alter session command to switch to point to the release schema (USER2) and…
-
Continue reading →: Oracle Audit Control part 2 – purging records
Now that you have got your audit table somewhere a little more sensible (i.e. not in the SYSTEM tablespace), there’s probably a policy about how many audit records should be kept. Thoughtfully, the DBMS_AUDIT_MGMT package provides some of what you need to keep the audit records in check. However, a little…
Neil Chandler's DB Blog 