Category: BLU

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Looking at Sort Memory Performance on BLU

Performance tuning of BLU databases is an evolving topic at this time. For BLU databases, sort memory cannot be tuned by STMM, and so must be manually tuned. BLU also makes extensive use of sort memory. It is a bit of a misnomer at this point. It is more of a working memory area that is used for hashes, grouping,...

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Administrative SQL Cookbook: BLU Buffer Pool Hit Ratios

Purpose These statements calculates the buffer pool hit ratio for both BLU and non-BLU activity. This post includes three SQLs – for calculating at the database, bufferpool, and tablespace level. The separate BLU calculations are not yet included in sysibadm.bp_hitratio as of the writing of this article. Source While I’ve modified this statement, it comes from these two sources, both...

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DB2 Administrative SQL Cookbook: Column Selectivity by Table (BLU)

Purpose This statement reports how selective at the column level queries are that run against a specific table. This does not look at overall selectivity or row selectivity. It will only work in DB2 10.5. BLU performs best when not all columns are referenced by queries. Source While I’ve modified this statement, it started with statements from these two sources,...

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DB2 Administrative SQL Cookbook: BLU Compression Ratios

Purpose This statement calculates the compression ratio for BLU tables. The compression ration can be used to help identify tables where compression is not optimal and you may need to look into why. Compression is critical to optimal performance on BLU. Understanding Compression Ratios. Compression ratios across platforms and outside of databases are generally represented as: Compression Ratio = Compressed...

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Issues with STMM

I thought I’d share some issues with STMM that I’ve seen on Linux lately. I’ve mostly been a fan of STMM, and I still am for small environments that are largely transaction processing and have only one instance on a server. Here are the details of this environment. The database is a small analytics environment. It used to be a...

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Giving Automatic Maintenance a Fair Try

I’m a control freak. I think that control freaks tend to make good DBAs as long as they don’t take it too far. My position for years has been that I would rather control my runstats, reorgs, and backups directly than trust DB2’s automatic facilities. But I also try to keep an open mind. That means that every so often...

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A Deeper Dive into DB2 BLU

I started out with a DB2 Basics entry on BLU. That starts with the most basic concepts. In this post, I’d like to delve into some of the details of BLU and talk about when BLU is beneficial and when it may be detrimental and why. BLU Workloads If you’re considering BLU consider first that it is not for all...

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Loading Data into DB2 BLU Tables

Working with BLU has been a glorious learning experience for me. I say that both truly with excitement and with frustration. Whenever I have a DBA-character building experience, I’m bound to share it with my readers. The Scenario A client has a small (1.7 TB) DPF data warehouse/ODS than I’m helping them move from 9.5 to 10.5 using BLU. Only...

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The IBM Data Movement Tool

We DBAs are lazy in some ways. Our favorite way of moving large amounts of data is the backup utility. It’s so easy to move data, structure, objects, permissions, etc. But as quick, easy, and efficient as it is, it cannot handle some situations – like skip-level upgrades, data movement between different operating systems, and of course between different RDBMSes....

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DB2 Basics: What is BLU?

BLU has been all the hype for DB2 for the past year or more. What exactly is DB2 BLU? How does it work? What do you need to consider before jumping on the bandwagon? What is DB2 BLU BLU leverages the DB2 engine but is a significantly different animal in many ways from DB2 without BLU. BLU combines a number...