ExecReScan for nodeAgg, nodeHash, nodeHashjoin, nodeNestloop and nodeResult.
Fixed ExecReScan for nodeMaterial.
Get rid of #ifdef INDEXSCAN_PATCH.
Get rid of ExecMarkPos and ExecRestrPos in nodeNestloop.
execute an sql function containing an utility command (create, notify, ...).
The bug is part in the planner, which returns a number of plans different
than the number of commands if there are utility commands in the query, and
in part in the function executor which assumes that all commands are normal
query commands and causes a SIGSEGV trying to execute commands without plan.
Submitted by: Massimo Dal Zotto <dz@cs.unitn.it>