Comments on: visualization of control-flow/data-flow analysis of sqlite EXPLAIN-ations

By: visophyte: shiny? shiny. :: performance annotated SQLite EXPLAINation visualizations using systemtap

Tue, 06 Apr 2010 10:44:58 +0000

[...] on my previous work on a visualization of SQLite opcode control flow graphs using graphviz I give you… the same [...]

By: Weave Intro & UI, Awesome Perf. (2009/9-1) | edilee

Weave Intro & UI, Awesome Perf. (2009/9-1) | edilee — Tue, 03 Mar 2009 16:55:19 +0000

[...] first made this tool to analyze his own query optimizations [visophyte.org], and now he’s made the code available for everyone to use and contribute [...]

By: Shawn Wilsher

Shawn Wilsher — Thu, 05 Feb 2009 15:39:20 +0000

I’ll note that you can tell SQLite to not use a column as an index by prefixing it with +. For example, in place where we have to join with a temp table, we do something like this:
SELECT *
FROM moz_places_temp
WHERE url LIKE ?1
UNION
SELECT *
FORM moz_places
WHERE +id NOT IN (SELECT id FROM moz_places_temp)
AND url LIKE ?1

By: Funtomas

Funtomas — Wed, 04 Feb 2009 21:48:44 +0000

Use of an index doesn’t automatically mean optimized search. Using Toad (by Quest SW) on Oracle, I’m sometimes surprised Oracle opts not to go with index as the Explain Plan says index-less searching costs less. Nevertheless, for index to be useful, its statistics need to be recalculated frequently.