Hi,

I'm having a hard time using an index scan. So far, I've done quite well with ScanKeyInit for equality searches. But now I need to scan an index from a given starting point. Something like:

   (x, y, z,...) > (const, const, const,...)

For the equality operatior, I've used get_sort_group_operators() in combination with get_opcode() to pass that on as the sk_func of the scan key. I slowly begin to doubt if that's correct at all.

While it works for equality scans, it does somehow not work for for BTGreaterStrategy. What am I missing?

I do have the following: an indexStruct on the index (primary key) I want to use, a TupleDescriptor for the relation I want tuples from and of course the list of constants (datums) to compare against. I want to do an index scan to retrieve tuples from that given lower bound upwards (or forwards).

I don't quite grok all the opfamily and opclass things, yet. Hints and pointers on where to read on greatly appreciated. A virtual beer for sample code. ;-)

Regards

Markus Wanner

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