Heikki Linnakangas <[EMAIL PROTECTED]> writes: > To recap, the sequence is:
> 1. COPY FROM > 2. checkpoint > 3. VACUUM > Now you have buffer cache full of dirty buffers with usage_count=1, Well, it won't be very full, because VACUUM works in a limited number of buffers (and did even before the BufferAccessStrategy patch). I have no doubt that there are scenarios such as you are thinking about, but it definitely seems like a corner case that doesn't justify keeping the all-buffers scan. That scan is costing us extra I/O in ordinary non-corner cases, so it's not free to keep it. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match