ALL POSTS

Meaning of “Disk Reads” Values in DBA_HIST_SQLSTAT

This post relates to my previous writing on mining the AWR. I noticed that it’s very easy to misinterpret the DISK_READS_TOTAL and DISK_READS_DELTA columns in DBA_HIST_SQLSTAT. Let’s see what the documentation says: DISK_READS_TOTAL – Cumulative number of disk reads for this child cursor DISK_READS_DELTA – Delta number of disk reads for this child cursor You…

SQL Server Risk Assessment – The PMP Way

Recently I had a chance to speak with my friend and colleague, Ashish Sharma. We were discussing Project Management topics (he recently passed PMP and ACP). Our discussion ended on a very interesting topic – RISK Assessment. Definition: According to PMBOK, projects can have unforeseen events or activities that can impact the project’s progress, result,…

Oracle Free Block Corruption – Test Case

My very first blog post at Pythian – Trick or Treat? So there I was, faced with more that 4000 block corruptions as shown from v$database_block_corruption. The script  corrupt_seg.sql identified the corruption as Free Block Corruption (block not associated with any segments). So how can free block corruption be removed? One method is to format the corrupted…

SQL Server Instance in Script Upgrade mode

Introduction: Almost all of us in our DBA life would have patch/upgrades SQL Server instance and would have faced many issues while upgrading the SQL Server build. Today I will discuss in little detail about the background of the Script Upgrade Mode and the fix. What is Script Upgrade mode: When we apply a patch…

Improve Gather Stats in Oracle E-Business Suite

One important aspect of a healthy Oracle database is database statistics. It’s the main data on which CBO feeds to generate good execution plans for SQLs. Implementing a periodic and consistent gather statistics procedure in Oracle E-Business Suite is every Applications DBA’s duty. But often I see that they are not set up properly to…

Magic Knobs in Replication Agents

Have you ever wondered about tuning your replication configuration to achieve better performance or you got into a situation of huge latency and were looking for an easier way to tune it. In this blog post, I will explain the very useful switches which are not always that obvious. Snapshot Agent BCPBatchSize – is the…

Using Amazon Web Services for MySQL at Scale Presentation

PalominoDB CEO Laine Campbell presented this class at the O’Reilly Velocity Conference, NYC Oct 2013. The class is broken into two videos and is a total of 85 minutes. Click here for Part 1 – Click here for Part 2  Laine will explain the options for running MySQL at high volumes at Amazon Web Services,…

Column Store Indexes in SQL Server 2012

Introduction: We will discuss Column Store Index and will try to understand the performance improvements of the same query by multiple times using column store index. What is Column store Index: Column Store Index is a feature introduced in SQL Server 2012 which helps us improve performance of data warehouse queries. It uses the VertiPaq, which stores…

Mining the AWR to Identify Performance Trends

Sometimes it’s useful to check how performance of a SQL statement changes over time. The diagnostic pack features provide some really useful information to answer these questions. The data is there, but it not always easy to retrieve it, especially if you want to see how the performance changes over time. I’ve been using three really…

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