Andrew Kyle Purtell created PHOENIX-7876:
--------------------------------------------
Summary: Improve EXPLAIN
Key: PHOENIX-7876
URL: https://issues.apache.org/jira/browse/PHOENIX-7876
Project: Phoenix
Issue Type: Improvement
Reporter: Andrew Kyle Purtell
Phoenix's {{EXPLAIN [WITH REGIONS]}} output is today incomplete and easy to
misread for both query analysis and performance investigation.
DDL EXPLAINs don't show columns/PK/families/salt/splits. Non-trivial joins
render with almost no detail. The cost vector advertises three dimensions but
only compares IO, and estimates/statistics are unreliable. Some optimizations
are incorrectly categorized, for example some shown as row-eliminating
predicates are actually column-projection optimizations. The operator trees of
complex queries are flattened to a single ident level. Many planner facts are
not surfaced at all, such as which rule chooses an index, which indexes the
optimizer considered but rejected, what query rewrites took place (e.g.
subquery decorrelation, star-join detection, right-to-left normalization,
HAVING lift, RVC-offset translation, reverse-scan substitution, UNION ORDER BY,
index expression substitution, and more), the specific hash-join strategy
chosen, salt bucket counts, local vs. global vs. uncovered-global index
distinctions, the particular flavor of atomic upsert chosen and server-side
atomic update expressions, multi tenant context, CDC scope, transaction
provider, projection lists, predicate to filter attribution, hints honored vs
ignored, and the structure of the JSON/BSON/array path expressions evaluated
server-side.
This proposal closes all of those gaps. Details provided in the design
document.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
