Category Archives: Performance

Using nz_zonemap to visualize Netezza’s zone map effectiveness

Netezza has a lot of tools in /nz/support/contrib/bin that make life for the NZ DBA much, MUCH easier.  One such tool is nz_zonemap. Zone maps are how the system keeps track of what records exist in a particular extent (3MB … Continue reading

Posted in administration, General, Performance | Tagged , , , , | 3 Comments

The relationship between groom and nzbackup

There are three basic functions that every Netezza DBA must perform regularly: Ensure statistics are up to date Groom your tables Backup your production databases Let’s focus on groom and its dependency on nzbackup.  I recently ran into an issue … Continue reading

Posted in administration, General, Performance, Uncategorized | Tagged , , , , | Leave a comment

IBM Netezza analytics to analyze query history table usage

Using Netezza’s in-database analytics package FPGROWTH, database administrators can identify the most commonly used combination of tables and the performance of the queries that reference those sets of tables. First, let’s see the most commonly used combination of tables.  Today, … Continue reading

Posted in administration, analytics, Performance | 2 Comments

Using Netezza query history to compare performance

Sometime way back when, Netezza introduced a more advanced query history recording mechanism that captured information about sessions, queries, plans, table access and column-level stats.  The great thing about this tool was that each entry in the query history table … Continue reading

Posted in administration, General, Performance | Leave a comment

Assessing query performance … by table?

While looking for performance optimization opportunities, I decided to look at things from a slightly different perspective: by table.  I’m not entirely sure how helpful this will be – but since I wrote the query I figured I’d put it … Continue reading

Posted in administration, General, Performance | Tagged , , | 2 Comments

Preserving plan files with rsync

Anytime you’ve wanted to investigate the execution plan of a query that ran days (or even hours) ago, you’ve probably found yourself disappointed that the plan file is no longer there.  That’s because Netezza only keeps a few thousand plans … Continue reading

Posted in administration, General, Performance | Tagged , | Leave a comment