Clarify a confusing comment about MCVs vs histogram entries.

Per Nathan Boley.

diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index ef10f1b26342e45cd3a883509d308935bc534578..5f6a2c42de6a5825f6ffc1c3ebc1366a0c58b7dc 100644 (file)
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.131 2009/01/01 17:23:37 momjian Exp $
+ *       $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.132 2009/01/06 23:46:06 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2149,7 +2149,9 @@ compute_scalar_stats(VacAttrStatsP stats,
                 * least 2 instances in the sample.  Also, we won't suppress values
                 * that have a frequency of at least 1/K where K is the intended
                 * number of histogram bins; such values might otherwise cause us to
-                * emit duplicate histogram bin boundaries.
+                * emit duplicate histogram bin boundaries.  (We might end up with
+                * duplicate histogram entries anyway, if the distribution is skewed;
+                * but we prefer to treat such values as MCVs if at all possible.)
                 */
                if (track_cnt == ndistinct && toowide_cnt == 0 &&
                        stats->stadistinct > 0 &&