diff --git a/contrib/findoidjoins/make_oidjoins_check b/contrib/findoidjoins/make_oidjoins_check
index 508d435c6d..b6a720a504 100755
--- a/contrib/findoidjoins/make_oidjoins_check
+++ b/contrib/findoidjoins/make_oidjoins_check
@@ -10,7 +10,8 @@
 # Caution: you may need to use GNU awk.
 AWK=${AWK:-awk}
 
-TMP="/tmp/$$"
+TMP="${TMPDIR:-/tmp}/make_oidjoins_check.$$"
+trap "rm -rf $TMP" 0 1 2 3 15
 
 # Create a temporary directory with the proper permissions so no one can
 # intercept our temporary files and cause a security breach.
@@ -23,8 +24,6 @@ fi
 umask "$OMASK"
 unset OMASK
 
-trap "rm -rf $TMP" 0 1 2 3 15
-
 INPUTFILE="$TMP/a"
 DUPSFILE="$TMP/b"
 NONDUPSFILE="$TMP/c"
diff --git a/doc/TODO b/doc/TODO
index afea981411..506db4e5c3 100644
--- a/doc/TODO
+++ b/doc/TODO
@@ -250,12 +250,17 @@ Indexes
   order. Another method would be to sort heap ctids matching the index
   before accessing the heap rows.
 
-* Use bitmaps to combine existing indexes [performance]
+* Allow the creation of bitmap indexes which can be quickly combined
+  with other bitmap indexes
 
-  Bitmap indexes allow single indexed columns to be combined to
-  dynamically create a composite index to match a specific query. Each
-  index is a bitmap, and the bitmaps are AND'ed or OR'ed to be combined.
+  Bitmap indexes index single columns and can be combined with other bitmap
+  indexes to dynamically create a composite index to match a specific query.
+  Each index is a bitmap, and the bitmaps are bitwise AND'ed or OR'ed to be
+  combined.
 
+* Allow non-bitmap indexes to be combined
+
+  Do loUse bitmaps to combine non-bitmap indexes
 * Allow use of indexes to search for NULLs
 
   One solution is to create a partial index on an IS NULL expression.