Posts by Alex Gorbachev
Looks like our blog has turned into a MySQL blog over this week, so I have to do something about it. Luckily, I have zillions of pending posts, so I’ll start with posting my presentations materials from this conference with my remarks on how it went in general.
I enjoyed the event and the venue very much. The presentations very generally very good, and to my surprise some of them were somewhat lighter than I would expect. However, that might actually play positively in extending the audience — there are only so many freaks interested only in hardcore performance and internals.
Unfortunately, I’m too slow to blog about news and can never make it first. Today is no exception and Doug Burns has already posted about “one of the best Oracle Conferences of all times”: I can tell you – I’m so excited to see all those bright people presenting. It’s especially a pleasure to see that Doug (who recently joined my team here at Pythian) is presenting there.
Oracle CRS 10.2.0.3 patchset brings long awaited removal of previously required dependencies of databases and ASM instances on a VIP. Actually, 10.2.0.2 patchset lifted the requirement for dependency between ASM instance and VIP but not for database instances. In 10.2.0.2 this dependency wasn’t removed by default. For those who don’t know…
Just a small thought to share. Oracle doesn’t really comply to the rule 11 of Codd’s 12 rules. It does have database links and tables can be grouped in different locations (databases) but it’s not possible to distribute a table transparently across several locations. MySQL Cluster, on the other hand, distributes rows of a table over different data nodes using hash function on the primary key and it’s transparent to the client so it conforms to the Rule 11 as opposed to Oracle.
This is a follow up on my previous post about SYSDBA keeping invoker rights when calling PL/SQL procedure. Working on the previous test case a bit more I figured that the same anomaly is observed with triggers. So here is one way to get your PL/SQL code called by a SYSDBA. In this case you need to be able to create trigger on database, i. e. need privileges ADMINISTER DATABASE TRIGGER and CREATE TRIGGER.
Oracle CRS 10.2.0.3 patchset changed the logging of missed heartbeats by CSS. Here is example how heartbeats misses are logged in ocssd.log in 10.2.0.3:
Doug Burns has spent 4 weeks in our Ottawa office and now he is back home to Madeline and boys. Yesterday, before he left, we had the lunch at Cock & Lion Ale House:
When checking for new known issues with 10.2.0.3 patchset on Metalink I discovered that an upgrade problem was added – Metalink Note 401435.1. The issue affects all 64 platforms especially when database is upgraded from any previous 32 bit release.
At the end of my last MySQL post I mentioned strange behavior with GROUP BY and DISTINCT. This MySQL “feature” could save some resources on sorts and aggregates but generally I would avoid it as this is not portable solution. Generally speaking, query output is non-deterministic — it depends on the full table scan implementation and on the physical order of rows in a table. This means that it’s actually a bug and , instead, MySQL should produce and error on those statements.