Hi I'm trying to gain a better understanding of how the postgres xlog works - especially about the corner cases of wal replay.
One thing that I do not understand is what CheckPoint.undo is used for. I grepped through the source, and only see very few references to it, which either just print it, or set it to the checkpoint location or the redo location. The only place where is is checked is if (XLByteLT(checkPoint.undo, RecPtr) || XLByteLT(checkPoint.redo, RecPtr)) but I don't see the reason for this check, given that undo never seems to be assigned any interesting value.. Is there any in-depth documentation about the postgres xlog implementation? What am I missing? greetings, Florian Pflug ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
