Tips & Tricks

Explain Enhancements

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This quick tip will demonstrate the behavior of two new EXPLAIN parameters (ALLNODES and JSON) added in 7.2.

The default EXPLAIN output still remains the same:

When a node is down, the plan looks like:

EXPLAIN /*+ALLNODES*/

Using the new /*+ALLNODES*/ parameter will assume that all nodes are up:

EXPLAIN JSON

With the new JSON parameter, it has become easier to store outputs for plan tuning (scroll):

EXPLAIN VERBOSE

As a reminder, the VERBOSE parameter is useful when estimating resource usage (scroll):

Sadly, the VERBOSE JSON version is not as verbose as the non-JSON output (scroll):

Read more in the documentation

About the author / 

Norbert Krupa

Norbert is the founder of vertica.tips and a Solutions Engineer at Talend. He is an HP Accredited Solutions Expert for Vertica Big Data Solutions. He has written the Vertica Diagnostic Queries which aim to cover monitoring, diagnostics and performance tuning. The views, opinions, and thoughts expressed here do not represent those of the user's employer.

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