Import wiredtiger: f441a501ba71c5c34ecbfc534e9c476155b151d1 from branch mongodb-3.6

ref: 6d142e23f7..f441a501ba
for: 3.6.11

WT-4483       Improve caching of small updates to large values

3 files changed, 20 insertions, 6 deletions

diff --git a/src/third_party/wiredtiger/import.data b/src/third_party/wiredtiger/import.data
index 5462f65ceae..b243bf2de39 100644
--- a/src/third_party/wiredtiger/import.data
+++ b/src/third_party/wiredtiger/import.data
@@ -1,5 +1,5 @@
 {
-    "commit": "6d142e23f7f8ada7d84487bbcb20bf5f54c737f9", 
+    "commit": "f441a501ba71c5c34ecbfc534e9c476155b151d1", 
     "github": "wiredtiger/wiredtiger.git", 
     "vendor": "wiredtiger", 
     "branch": "mongodb-3.6"
diff --git a/src/third_party/wiredtiger/src/btree/bt_cursor.c b/src/third_party/wiredtiger/src/btree/bt_cursor.c
index 886ea0b68f9..199c57972d7 100644
--- a/src/third_party/wiredtiger/src/btree/bt_cursor.c
+++ b/src/third_party/wiredtiger/src/btree/bt_cursor.c
@@ -1395,10 +1395,11 @@ __cursor_chain_exceeded(WT_CURSOR_BTREE *cbt)
 		upd_size += WT_UPDATE_MEMSIZE(upd);
 		if (upd_size >= WT_MODIFY_MEM_FACTOR * cursor->value.size)
 			return (true);
-		if (__wt_txn_upd_visible_all(session, upd) &&
-		    i >= WT_MAX_MODIFY_UPDATE)
-			return (true);
 	}
+	if (upd != NULL && upd->type == WT_UPDATE_STANDARD &&
+	    __wt_txn_upd_visible_all(session, upd) &&
+	    i >= WT_MAX_MODIFY_UPDATE)
+		return (true);
 	return (false);
 }
 
diff --git a/src/third_party/wiredtiger/src/btree/bt_read.c b/src/third_party/wiredtiger/src/btree/bt_read.c
index 0d0cf17762c..1254b86c6ea 100644
--- a/src/third_party/wiredtiger/src/btree/bt_read.c
+++ b/src/third_party/wiredtiger/src/btree/bt_read.c
@@ -317,6 +317,7 @@ __evict_force_check(WT_SESSION_IMPL *session, WT_REF *ref)
 {
 	WT_BTREE *btree;
 	WT_PAGE *page;
+	size_t footprint;
 
 	btree = S2BT(session);
 	page = ref->page;
@@ -332,8 +333,20 @@ __evict_force_check(WT_SESSION_IMPL *session, WT_REF *ref)
 	if (__wt_page_evict_clean(page))
 		return (false);
 
+	/*
+	 * Exclude the disk image size from the footprint checks.  Usually the
+	 * disk image size is small compared with the in-memory limit (e.g.
+	 * 16KB vs 5MB), so this doesn't make a big difference.  Where it is
+	 * important is for pages with a small number of large values, where
+	 * the disk image size takes into account large values that have
+	 * already been written and should not trigger forced eviction.
+	 */
+	footprint = page->memory_footprint;
+	if (page->dsk != NULL)
+		footprint -= page->dsk->mem_size;
+
 	/* Pages are usually small enough, check that first. */
-	if (page->memory_footprint < btree->splitmempage)
+	if (footprint < btree->splitmempage)
 		return (false);
 
 	/*
@@ -346,7 +359,7 @@ __evict_force_check(WT_SESSION_IMPL *session, WT_REF *ref)
 	/* If we can do an in-memory split, do it. */
 	if (__wt_leaf_page_can_split(session, page))
 		return (true);
-	if (page->memory_footprint < btree->maxmempage)
+	if (footprint < btree->maxmempage)
 		return (false);
 
 	/* Bump the oldest ID, we're about to do some visibility checks. */