Did you consider the use of simple_list.c instead of introducing a new mimic as PGcommandQueueEntry? It would be cool avoiding adding new list emulations on frontends.
I'd have to extend simple_list to add a generic object version, like
struct my_list_elem
{
PG_SIMPLE_LIST_ATTRS;
mytype mycol;
myothertype myothercol;
}
Objections?
I could add a void* version that's a simple clone of the string version, but having to malloc both a list cell and its contents separately is annoying.
