Repair out-of-date information in src/backend/storage/buffer/README.

In commit d526575f893c1a4e05ebd307e80203536b213a6d, we changed things so
that buffer usage counts are incremented when the buffer is pinned, rather
than when it is unpinned, but the README file didn't get the memo.

Report by Amit Kapila.

diff --git a/src/backend/storage/buffer/README b/src/backend/storage/buffer/README
index 38e67c1c905cb490327aaca03979b1239cf3cc24..6fd961206b5026d0d6c60eaf0652895b33b63068 100644 (file)
--- a/src/backend/storage/buffer/README
+++ b/src/backend/storage/buffer/README
@@ -169,8 +169,8 @@ need to take system-wide locks during common operations.  It works like
 this:
 
 Each buffer header contains a usage counter, which is incremented (up to a
-small limit value) whenever the buffer is unpinned.  (This requires only the
-buffer header spinlock, which would have to be taken anyway to decrement the
+small limit value) whenever the buffer is pinned.  (This requires only the
+buffer header spinlock, which would have to be taken anyway to increment the
 buffer reference count, so it's nearly free.)
 
 The "clock hand" is a buffer index, NextVictimBuffer, that moves circularly