Hi, By inspection of plperl and plpython, it looks like the canonical pattern for a PL using internal subtransactions is:
save CurrentMemoryContext save CurrentResourceOwner BeginInternalSubTransaction reimpose the saved memory context // but not the saved resource owner ... (RollbackAnd)?ReleaseCurrentSubTransaction reimpose the saved memory context and the saved resource owner Therefore, during the subtransaction, its newly-established memory context is accessible as CurTransactionMemoryContext, but the caller can still use CurrentMemoryContext to refer to the same context it already expected. By contrast, the newly established resource owner is both the CurTransactionResourceOwner and the CurrentResourceOwner within the scope of the subtransaction. Is there more explanation of this pattern written somewhere than I have managed to find, and in particular of the motivation for treating the memory context and the resource owner in these nearly-but-not-quite matching ways? Regards, -Chap
