Author: Craig Mullins

Consultant at Mullins Consulting, Inc

Craig Mullins

Craig S. Mullins is working with Datavail and its DB2 practice to expand offerings. He is president and principal consultant at Mullins Consulting, Inc. and the publisher of The Database Site. Mullins has 30 years of experience in all facets of database management and is the author of two books: “DB2 Developer’s Guide” currently in its 6th edition and “Database Administration: The Complete Guide to DBA Practices and Procedures,” the industry’s only guide to heterogeneous DBA.

Articles Written by Craig Mullins

VSAM is used "under the covers" of every DB2 for z/OS page set. VSAM is also used as the storage mechanism by some IMS databases. It is also used to store a lot of mainframe data outside the control of any DBMS. But there is a lot of confusion about what exactly VSAM is, how it can be used, and how it differs from a DBMS.

Read More

I frequently get e-mails with DB2 questions and I plan to start posting answers to some of the more common ones up here. One issue that comes up a lot is dealing with locking issues. Usually it is posed by someone who is experiencing timeouts in an online environment and they want to know how to minimize them. Here is some guidance.

Read More

I've written about this subject before, but I think it is important enough to merit another go-round. First of all, before I go any further, let's first define what I mean by a “black box.” If I plan to recommend that you prohibit them we better both understand what it is we are talking about proscribing.

Read More

Data compression for non-mainframe DB2 is quite a bit different than it is for DB2 for z/OS. In mainframe DB2, specifying COMPRESS YES on the CREATE TABLESPACE statement will cause DB2 to implement Ziv-Lempel compression for the table space in question. Data is compressed upon entry to the database and decompressed when it is read.

Read More

A continuing, lingering perception that the mainframe is dead continues on in some parts of the IT industry. It seems that we constantly hear that big IT shops are getting rid of their mainframes. But rarely do we ever hear about it after the fact. No, it is usually reported right when someone thinks that it is a good idea.

Read More

Database performance problems are not caused by magic. Indeed, all performance problems are always caused by change. That statement flies in the face of what I normally say, which is “Almost never say always or never”… but in this case, it is true.

Read More