It seems like there are not many Oracle Restart environments (or there are but Oracle doesn’t pay too much attention to them). Otherwise, I can’t explain why I couldn’t find too much information about it in the documentation when it comes to upgrades.
So, to help all of you out there that do use it, here are some notes about the upgrade process.
Continue reading “Upgrade Oracle Restart to 18c”
During a performance problem I had with a query I wanted to create an index on the table. Since this was a large table I wanted the index to include all the needed columns so I won’t need to access the table at all. The query also used GROUP BY and MAX, so I thought a descending index would be best, as it will easier for Oracle to find the highest value (as it will be the first one).
Continue reading “Strange Index Behavior”
This is an old story. It started in 2015 when I found a problem with TOP-N query performance. I wrote a blog post about it and later an update. Here I want to show the full testcase and some updates after a twitter discussion.
Continue reading “Top-N Queries”
I had a bad night last Thursday.
After patching two test RAC databases and one production RAC with 180417 DB Bundle Patch (and some one-offs), I got to the point where it was time to update the most critical RAC system.
We were really looking forward to this as we had hit a few bugs that this DBBP and one-offs should fix. But boy, did that go wrong…
Continue reading “Bug When Patching Production”
Lately I started patching a client’s database (220.127.116.11) to the latest PSU (180417). This is a RAC environment with streams and all kind of other features, so over the time we hit quite a lot of different bugs. When we planned this PSU (we installed the bundle patch version), we added about 7 one-off patches (some are recommended by Oracle and some we had to add because the bugs affected us quite badly).
Continue reading “One-off Patch Frustration”
This post is following a question I found on LinkedIn. A DBA pasted a strange test case in 18.104.22.168 and I managed to reproduce it in 22.214.171.124 (non-multitenant) and 12.2 (multitenant). But that’s not where the story ends, I wanted to understand what’s going on, so I did some research about it and the result is this post.
Continue reading “Non-existent Objects (and possibly a bug)”
A few months ago we hit an Oracle bug related to streams replication crash after creating an index (bug 21320182). There is a patch so we installed the patch in test and it seemed to solve the problem, but we never patched the production.
Today we hit this issue in production after creating an index we needed. It’s important to say that we wanted to patch the prod a while ago, but we didn’t get approval for maintenance window.
Continue reading “Researching a Bug”