I've started working on something I've ended up calling "Super PathKeys". The idea here is to increase the likelihood of a Path with PathKeys being used for a purpose that requires a less strict sort order due to ordering being required from the return value of some precision loss function.
Anything left anchored would benefit, so SUBSTR(), TRIM() etc
Main use for this would be where the partition condition is a function, so we can still order by partitions easily.
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Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
