Pro Tips on Managing Data at Scale
As a DBA I worked on a number of projects fighting fires and putting them off successfully. However in the beginning of my career I was not sure where to start, as I matured as a DBA there is a pattern that developed to troubleshoot performance issues. Each of the following areas need different kind … Read more
If you are looking to generate load from cursor command for a bunch of schema’s at once, this SQL is your friend!
Problem: How would you generate a report of the top 10 most active tables of your DB2 database ? To be more precise how would you generate a list of top 10 tables that are being Read/Inserted/Updated/Deleted and also against which most table scans are happening ? Solution: Use the following SQL to generate a … Read more
Problem: As a DBA, you may get asked by development/other teams to get the list of duplicate rows based on a certain column or a key (non-primary). In this short blog post I am going to discuss a couple of ways to get the list of duplicates. Solution: For e.g. lets assume you have a … Read more
Problem: I was contacted by fellow team members saying replication from their non-Db2 RDBMS to DB2 has been running with a lot of latency and they are noticing slowness specifically with deletes. Third party Replication software logs are also logging that latency is on the target Db2 side. This is not a recurring problem as … Read more
The reason I am posting this article is I have worked in a number of places as a DBA and I must admit that I worked in places that were run meticulously and also worked in places where the Db2 and application were running on a single mount point “/” (root) on the same … Read more
Problem Statement: A redundant index in my book can have one or more leading columns that match with any other existing index leading columns on a given table. As a DBA I worked in many places where this is a reccurring problem. Many DBA’s are hesitant to drop these redundant indexes despite number of disadvantages … Read more
While working in a pureScale environment, I learned that db2cluster command is not the quickest way to get the information you are looking for. If you are working on troubleshooting a problem, waiting for db2cluster command to return the output could be frustrating. Depending on the state of your pureScale cluster it is possible that … Read more
In this blog post I am going to talk about how DB2 optimizer can underestimate or overestimate join ratios or cardinalities resulting from join operations and a few other situations. This topic is very broad and need multiple other blog entries to cover in detail. However in this blog post at a very high level … Read more
Problem: You would like to find out quickly how much space your tablespaces are utilizing and how much space is being wasted below the high watermark with in a tablespace, how would you look for it ? While there are multiple ways to pull out that information but ever since MON_GET functions were introduced I … Read more
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