Change split percentage calculation to round to the nearest allocation size.

Rather than always rounding up to the next allocation size. Avoid
rounding where it puts us at the start or end of the page size.

1 files changed, 9 insertions, 1 deletions

diff --git a/src/reconcile/rec_write.c b/src/reconcile/rec_write.c
index f6521013ed9..2a37f0f8189 100644
--- a/src/reconcile/rec_write.c
+++ b/src/reconcile/rec_write.c
@@ -1889,7 +1889,15 @@ __wt_split_page_size(WT_BTREE *btree, uint32_t maxpagesize)
 	 * we don't waste space when we write).
 	 */
 	a = maxpagesize;			/* Don't overflow. */
-	split_size = (uint32_t)((a * (u_int)btree->split_pct) / 100);
+	split_size = (uint32_t)WT_ALIGN_NEAREST(
+	    (a * (u_int)btree->split_pct) / 100, btree->allocsize);
+
+	/*
+	 * Respect the configured split percentage if the calculated split
+	 * size is either zero or a full page.
+	 */
+	if (split_size == 0 || split_size == maxpagesize)
+		split_size = (uint32_t)((a * (u_int)btree->split_pct) / 100);
 
 	return (split_size);
 }