Db2 Experts on a Data Science Quest
I often lean on analogies when I speak to non-technical people about technical topics. For example, I would explain database locking as “two kids fighting for the same candy bar”. If you introduce isolation levels into the conversation, I would expand the analogy to include “one sibling holding on to a candy bar they care nothing about just because they don’t want the other sibling getting to it”.… Read the rest
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Loading data into a DB2 database using the LOAD utility has a lot of ins and outs. If a DBA has spent a lot of time working in a database without referential integrity or check constraints, then they may forget to check for tables in a check-pending state after loading data.… Read the rest
Continue reading »While this post is specific to WebSphere Commerce, it covers concepts that may apply to tuning other delete statements as well.
The CLEANCONF table stores the delete statements that are used by DBCLEAN. Most of them use syntax like this for the date component:
(days(CURRENT TIMESTAMP) - days(prevlastsession)) = ?… Read the rest Continue reading »
The request from the developers was something along the lines of “Help, Ember, this query needs to perform better”. Sometimes the query I’m working on is not one that shows up as a problem from the database administrator’s perspective, but one that is especially important in some part of application functioning.… Read the rest
Continue reading » Today we are going to talk about some random DB2 features that can’t stand in a blog of their own, but are worth discussing nonetheless. These are tidbits I had discovered during “DB2’s Got Talent” presentations, IDUG conferences, or “Hey, look what I discovered” moments.… Read the rest
Like many applications, WebSphere Commerce puts all tables in USERSPACE1 unless they need larger page sizes. This actually works just fine for smaller and midrange implementations, but we have about one build a year that requires something else – either because of standards that client DBAs adhere to or because they actually are busy enough for I/O and separate buffer pools to matter.… Read the rest
Go-lives bring all kinds of opportunities to find problem SQL. A new site going live or a new site design going live can put a completely different load of SQL on a database. Depending on the level of load testing done, there can be some problems still to find.… Read the rest
Continue reading »I don’t often make changes to existing tables. The WebSphere Commerce database comes with defintions in place. We make customizations that are largely adding columns or adding tables or adding indexes. It is pretty rare that we have to alter one of the handful of custom tables in some way.… Read the rest
Continue reading »I work on a team of DBAs, and we will frequently talk through an issue together to find the root cause. We are all capable of getting there on our own, but sometimes we realize that we’re not seeing something or think one of the others might see an issue faster.… Read the rest
Continue reading »This post is specific to WebSphere Commerce.
One of the most frequent things I do is to look up whether a table is a part of stagingprop.
The most obvious time to check is when someone asks “Is this table a part of stagingprop”.… Read the rest
Continue reading »This post is specific to WebSphere Commerce.
I ran into a new stagingprop failure today(which doesn’t happen all that often anymore), and it taught me something about custom staging triggers, too.
Stagingprop fails, and a message such as this this in the stagingprop log.… Read the rest
Continue reading »One of my most popular posts that’s specific to WebSphere Commerce is The 10 Commerce Tables You Should Be Familiar With. This is an updated version of that post, since the preferred method of dealing with attributes has changed. As a result, this post is only applicable to WebSphere Commerce 7 and above, and some of the content is identical between the two posts.… Read the rest
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