From f6ddb0cdddfb2bb0c3195edcbb60d3ca5f679a90 Mon Sep 17 00:00:00 2001 From: John Naylor Date: Tue, 5 Feb 2019 10:42:18 +0100 Subject: [PATCH v1 2/2] Add note that relations with no FSM will report no free space. --- contrib/pgstattuple/pgstatapprox.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/contrib/pgstattuple/pgstatapprox.c b/contrib/pgstattuple/pgstatapprox.c index ff7c255a2d..23ccaaaca6 100644 --- a/contrib/pgstattuple/pgstatapprox.c +++ b/contrib/pgstattuple/pgstatapprox.c @@ -89,6 +89,8 @@ statapprox_heap(Relation rel, output_type *stat) /* * If the page has only visible tuples, then we can find out the free * space from the FSM and move on. + * Note: If a relation has no FSM, GetRecordedFreeSpace() will report + * zero free space. This is fine for the purposes of approximation. */ if (VM_ALL_VISIBLE(rel, blkno, &vmbuffer)) { -- 2.17.1