WT-3652 Skip unnecessary lookaside reads / writes. (#3744)

Also fix reads during checkpoint so the expected read generation is
set, and checkpoint can attempt to clean up after itself.

Add a "lookaside_score" measuring the proportion of unstable updates in
cache (those required for historic reads), use that to determine when
to use the lookaside table rather than waiting for the cache to become
stuck.

Instead of discarding updates as part of restoring a page, including the original value in the update list if the on-page update is a modify.  This removes some problematic code that was inconsistent about removing updates.  Also, if we need to restore updates earlier than the on-page version, the previous code was incorrect.

Disable checkpoint skipping lookaside pages for now: always visit every page until we are tracking the correct IDs and timestamps to skip properly.

Ensure all trees with lookaside pages must stay dirty.

13 files changed, 407 insertions, 328 deletions

diff --git a/dist/stat_data.py b/dist/stat_data.py
index 24610b9ab14..64d3d46818b 100644
--- a/dist/stat_data.py
+++ b/dist/stat_data.py
@@ -257,6 +257,7 @@ connection_stats = [
     CacheStat('cache_lookaside_entries', 'lookaside table entries', 'no_clear,no_scale'),
     CacheStat('cache_lookaside_insert', 'lookaside table insert calls'),
     CacheStat('cache_lookaside_remove', 'lookaside table remove calls'),
+    CacheStat('cache_lookaside_score', 'lookaside score', 'no_clear,no_scale'),
     CacheStat('cache_overhead', 'percentage overhead', 'no_clear,no_scale'),
     CacheStat('cache_pages_dirty', 'tracked dirty pages in the cache', 'no_clear,no_scale'),
     CacheStat('cache_pages_inuse', 'pages currently held in the cache', 'no_clear,no_scale'),
diff --git a/src/btree/bt_read.c b/src/btree/bt_read.c
index 2dd366d8d5e..eaf025d5468 100644
--- a/src/btree/bt_read.c
+++ b/src/btree/bt_read.c
@@ -430,6 +430,61 @@ err:	/*
 }
 
 /*
+ * __page_in_lookaside_check --
+ *	Review lookaside page references for page in
+ */
+static inline int
+__page_in_lookaside_check(WT_SESSION_IMPL *session, WT_REF *ref)
+{
+	WT_TXN *txn;
+	WT_TXN_GLOBAL *txn_global;
+
+	txn = &session->txn;
+	txn_global = &S2C(session)->txn_global;
+
+	/*
+	 * Skip lookaside pages if reading without a timestamp and all the
+	 * updates in lookaside are in the past.
+	 *
+	 * If we skip a lookaside page, the tree cannot be left clean:
+	 * lookaside entries must be resolved before the tree can be discarded.
+	 *
+	 * Lookaside eviction preferentially chooses the newest updates when
+	 * creating page image with no stable timestamp.  If a stable timestamp
+	 * has been set, we have to visit the page because eviction chooses old
+	 * version of records in that case.
+	 *
+	 * One case where we may need to visit the page is if lookaside
+	 * eviction is active in tree 2 when a checkpoint has started and is
+	 * working its way through tree 1.  In that case, lookaside may have
+	 * created a page image with updates in the future of the checkpoint.
+	 */
+	if (!F_ISSET(txn, WT_TXN_HAS_TS_READ) &&
+	    F_ISSET(txn, WT_TXN_HAS_SNAPSHOT) &&
+	    !txn_global->has_stable_timestamp &&
+	    WT_TXNID_LT(ref->page_las->las_max_txn,
+	    txn->snap_min)) {
+		__wt_tree_modify_set(session);
+		return (WT_NOTFOUND);
+	}
+#ifdef HAVE_TIMESTAMPS
+	/*
+	 * Skip lookaside pages if reading as of a timestamp and all the
+	 * updates are in the future.
+	 */
+	if (F_ISSET(&session->txn, WT_TXN_HAS_TS_READ) &&
+	    txn_global->has_stable_timestamp &&
+	    WT_TXNID_LT(ref->page_las->las_max_txn, txn->snap_min) &&
+	    __wt_timestamp_cmp(
+	    &ref->page_las->min_timestamp, &session->txn.read_timestamp) > 0) {
+		__wt_tree_modify_set(session);
+		return (WT_NOTFOUND);
+	}
+#endif
+	return (0);
+}
+
+/*
  * __wt_page_in_func --
  *	Acquire a hazard pointer to a page; if the page is not in-memory,
  *	read it from the disk and build an in-memory version.
@@ -473,23 +528,8 @@ __wt_page_in_func(WT_SESSION_IMPL *session, WT_REF *ref, uint32_t flags
 				if (ref->state != WT_REF_LOOKASIDE ||
 				    !LF_ISSET(WT_READ_LOOKASIDE))
 					return (WT_NOTFOUND);
-#ifdef HAVE_TIMESTAMPS
-				/*
-				 * Skip lookaside pages if reading as of a
-				 * timestamp and all the updates are in the
-				 * future.  If we skip a lookaside page, the
-				 * tree cannot be left clean: it must be
-				 * visited by future checkpoints.
-				 */
-				if (F_ISSET(
-				    &session->txn, WT_TXN_HAS_TS_READ) &&
-				    __wt_timestamp_cmp(
-				    &ref->page_las->min_timestamp,
-				    &session->txn.read_timestamp) > 0) {
-					__wt_tree_modify_set(session);
-					return (WT_NOTFOUND);
-				}
-#endif
+
+				WT_RET(__page_in_lookaside_check(session, ref));
 			}
 
 			/*
@@ -603,7 +643,7 @@ __wt_page_in_func(WT_SESSION_IMPL *session, WT_REF *ref, uint32_t flags
 				continue;
 			}
 
-			/*
+skip_evict:		/*
 			 * If we read the page and are configured to not trash
 			 * the cache, and no other thread has already used the
 			 * page, set the read generation so the page is evicted
@@ -622,7 +662,7 @@ __wt_page_in_func(WT_SESSION_IMPL *session, WT_REF *ref, uint32_t flags
 					__wt_cache_read_gen_new(session, page);
 			} else if (!LF_ISSET(WT_READ_NO_GEN))
 				__wt_cache_read_gen_bump(session, page);
-skip_evict:
+
 			/*
 			 * Check if we need an autocommit transaction.
 			 * Starting a transaction can trigger eviction, so skip
diff --git a/src/btree/bt_split.c b/src/btree/bt_split.c
index 66f0478c542..24c88128a0e 100644
--- a/src/btree/bt_split.c
+++ b/src/btree/bt_split.c
@@ -1383,7 +1383,7 @@ __split_multi_inmem(
 	WT_DECL_RET;
 	WT_PAGE *page;
 	WT_SAVE_UPD *supd;
-	WT_UPDATE *prev_upd, *upd;
+	WT_UPDATE *upd;
 	uint64_t recno;
 	uint32_t i, slot;
 
@@ -1474,36 +1474,6 @@ __split_multi_inmem(
 			break;
 		WT_ILLEGAL_VALUE_ERR(session);
 		}
-
-		/*
-		 * Discard the update used to create the on-page disk image.
-		 * This is not just a performance issue: if the update used to
-		 * create the value for this on-page disk image was a modify,
-		 * and it was applied to the previous on-page value to
-		 * determine a value to write to this disk image, that update
-		 * cannot be applied to the new on-page value without risking
-		 * corruption.
-		 */
-		if (supd->onpage_upd != NULL) {
-			for (prev_upd = upd; prev_upd != NULL &&
-			    prev_upd->next != supd->onpage_upd;
-			    prev_upd = prev_upd->next)
-				;
-			/*
-			 * If the on-page update was in fact a tombstone, there
-			 * will be no value on the page.  Don't throw the
-			 * tombstone away: we may need it to correctly resolve
-			 * modifications.
-			 */
-			if (supd->onpage_upd->type == WT_UPDATE_DELETED &&
-			    prev_upd != NULL)
-				prev_upd = prev_upd->next;
-			if (prev_upd != NULL) {
-				__wt_update_obsolete_free(
-				    session, page, prev_upd->next);
-				prev_upd->next = NULL;
-			}
-		}
 	}
 
 	/*
@@ -1673,6 +1643,7 @@ __wt_multi_to_ref(WT_SESSION_IMPL *session,
 
 		WT_RET(__wt_calloc_one(session, &ref->page_las));
 		ref->page_las->las_pageid = multi->las_pageid;
+		ref->page_las->las_max_txn = multi->las_max_txn;
 #ifdef HAVE_TIMESTAMPS
 		__wt_timestamp_set(
 		    &ref->page_las->min_timestamp, &multi->las_min_timestamp);
diff --git a/src/conn/conn_cache.c b/src/conn/conn_cache.c
index c83fb544982..007aa8757da 100644
--- a/src/conn/conn_cache.c
+++ b/src/conn/conn_cache.c
@@ -266,6 +266,19 @@ __wt_cache_stats_update(WT_SESSION_IMPL *session)
 	WT_STAT_SET(session, stats, cache_pages_dirty,
 	    cache->pages_dirty_intl + cache->pages_dirty_leaf);
 
+	WT_STAT_CONN_SET(session, cache_eviction_state, cache->flags);
+	WT_STAT_CONN_SET(session,
+	    cache_eviction_aggressive_set, cache->evict_aggressive_score);
+	WT_STAT_CONN_SET(session,
+	    cache_eviction_empty_score, cache->evict_empty_score);
+	WT_STAT_CONN_SET(session,
+	    cache_lookaside_score, __wt_cache_lookaside_score(cache));
+
+	WT_STAT_CONN_SET(session,
+	    cache_eviction_active_workers, conn->evict_threads.current_threads);
+	WT_STAT_CONN_SET(session, cache_eviction_stable_state_workers,
+	    cache->evict_tune_workers_best);
+
 	/*
 	 * The number of files with active walks ~= number of hazard pointers
 	 * in the walk session.  Note: reading without locking.
diff --git a/src/evict/evict_lru.c b/src/evict/evict_lru.c
index daee1b3d29a..2e559531f4b 100644
--- a/src/evict/evict_lru.c
+++ b/src/evict/evict_lru.c
@@ -617,8 +617,6 @@ __evict_update_work(WT_SESSION_IMPL *session)
 		F_CLR(cache, WT_CACHE_EVICT_CLEAN | WT_CACHE_EVICT_CLEAN_HARD);
 	}
 
-	WT_STAT_CONN_SET(session, cache_eviction_state, cache->flags);
-
 	return (F_ISSET(cache, WT_CACHE_EVICT_ALL | WT_CACHE_EVICT_URGENT));
 }
 
@@ -727,9 +725,6 @@ __evict_pass(WT_SESSION_IMPL *session)
 				    txn_global->current != oldest_id &&
 				    cache->evict_aggressive_score < 100)
 					++cache->evict_aggressive_score;
-				WT_STAT_CONN_SET(session,
-				    cache_eviction_aggressive_set,
-				    cache->evict_aggressive_score);
 				prev = now;
 				prev_oldest_id = oldest_id;
 			}
@@ -761,12 +756,8 @@ __evict_pass(WT_SESSION_IMPL *session)
 			    "%s", "unable to reach eviction goal");
 			break;
 		} else {
-			if (cache->evict_aggressive_score > 0) {
+			if (cache->evict_aggressive_score > 0)
 				--cache->evict_aggressive_score;
-				WT_STAT_CONN_SET(session,
-				    cache_eviction_aggressive_set,
-				    cache->evict_aggressive_score);
-			}
 			loop = 0;
 			eviction_progress = cache->eviction_progress;
 		}
@@ -1098,12 +1089,7 @@ __evict_tune_workers(WT_SESSION_IMPL *session)
 				WT_STAT_CONN_INCR(session,
 				    cache_eviction_worker_removed);
 			}
-			WT_STAT_CONN_SET(session,
-			    cache_eviction_stable_state_workers,
-			    cache->evict_tune_workers_best);
 			cache->evict_tune_stable = true;
-			WT_STAT_CONN_SET(session, cache_eviction_active_workers,
-			    conn->evict_threads.current_threads);
 			goto done;
 		}
 	}
@@ -1135,9 +1121,6 @@ __evict_tune_workers(WT_SESSION_IMPL *session)
 		cache->evict_tune_last_action_time = current_time;
 	}
 
-	WT_STAT_CONN_SET(session, cache_eviction_active_workers,
-	    conn->evict_threads.current_threads);
-
 done:	cache->evict_tune_last_time = current_time;
 	cache->evict_tune_progress_last = eviction_progress;
 }
@@ -1187,11 +1170,8 @@ __evict_lru_walk(WT_SESSION_IMPL *session)
 	cache = S2C(session)->cache;
 
 	/* Age out the score of how much the queue has been empty recently. */
-	if (cache->evict_empty_score > 0) {
+	if (cache->evict_empty_score > 0)
 		--cache->evict_empty_score;
-		WT_STAT_CONN_SET(session, cache_eviction_empty_score,
-		    cache->evict_empty_score);
-	}
 
 	/* Fill the next queue (that isn't the urgent queue). */
 	queue = cache->evict_fill_queue;
@@ -1221,14 +1201,10 @@ __evict_lru_walk(WT_SESSION_IMPL *session)
 	 */
 	if (__evict_queue_empty(queue, false)) {
 		if (F_ISSET(cache,
-		    WT_CACHE_EVICT_CLEAN_HARD | WT_CACHE_EVICT_DIRTY_HARD)) {
+		    WT_CACHE_EVICT_CLEAN_HARD | WT_CACHE_EVICT_DIRTY_HARD))
 			cache->evict_empty_score = WT_MIN(
 			    cache->evict_empty_score + WT_EVICT_SCORE_BUMP,
 			    WT_EVICT_SCORE_MAX);
-			WT_STAT_CONN_SET(session,
-			    cache_eviction_empty_score,
-			    cache->evict_empty_score);
-		}
 		WT_STAT_CONN_INCR(session, cache_eviction_queue_empty);
 	} else
 		WT_STAT_CONN_INCR(session, cache_eviction_queue_not_empty);
diff --git a/src/evict/evict_page.c b/src/evict/evict_page.c
index edf80ec4460..d0128d8bcdd 100644
--- a/src/evict/evict_page.c
+++ b/src/evict/evict_page.c
@@ -576,18 +576,13 @@ __evict_review(
 			}
 
 			/*
-			 * If the cache is nearly stuck, check if
-			 * reconciliation suggests trying the lookaside table
-			 * unless lookaside eviction is disabled globally.
-			 *
-			 * We don't wait until the cache is completely stuck:
-			 * for workloads where lookaside eviction is necessary
-			 * to make progress, we don't want a single successful
-			 * page eviction to make the cache "unstuck" so we have
-			 * to wait again before evicting the next page.
+			 * If the cache is under pressure with many updates
+			 * that can't be evicted, check if reconciliation
+			 * suggests trying the lookaside table.
 			 */
-			if (__wt_cache_nearly_stuck(session) &&
-			    !F_ISSET(conn, WT_CONN_EVICTION_NO_LOOKASIDE))
+			if (!F_ISSET(conn, WT_CONN_EVICTION_NO_LOOKASIDE) &&
+			    (__wt_cache_lookaside_score(cache) > 50 ||
+			    __wt_cache_stuck(session)))
 				lookaside_retryp = &lookaside_retry;
 		}
 	}
diff --git a/src/include/btmem.h b/src/include/btmem.h
index 158fcf87d29..8662c40c635 100644
--- a/src/include/btmem.h
+++ b/src/include/btmem.h
@@ -242,6 +242,7 @@ struct __wt_page_modify {
 
 		/* The page has lookaside entries. */
 		uint64_t las_pageid;
+		uint64_t las_max_txn;
 		WT_DECL_TIMESTAMP(las_min_timestamp)
 	} r;
 #undef	mod_replace
@@ -250,6 +251,8 @@ struct __wt_page_modify {
 #define	mod_disk_image	u1.r.disk_image
 #undef	mod_replace_las_pageid
 #define	mod_replace_las_pageid	u1.r.las_pageid
+#undef	mod_replace_las_max_txn
+#define	mod_replace_las_max_txn	u1.r.las_max_txn
 #undef	mod_replace_las_min_timestamp
 #define	mod_replace_las_min_timestamp	u1.r.las_min_timestamp
 
@@ -298,6 +301,7 @@ struct __wt_page_modify {
 		uint32_t checksum;
 
 		uint64_t las_pageid;
+		uint64_t las_max_txn;
 		WT_DECL_TIMESTAMP(las_min_timestamp)
 	} *multi;
 	uint32_t multi_entries;		/* Multiple blocks element count */
@@ -726,6 +730,8 @@ struct __wt_page_deleted {
  */
 struct __wt_page_lookaside {
 	uint64_t las_pageid;			/* Page ID in lookaside */
+	uint64_t las_max_txn;			/* Maximum transaction ID in
+						   lookaside */
 	WT_DECL_TIMESTAMP(min_timestamp)	/* Oldest timestamp in
 						   lookaside for the page */
 };
diff --git a/src/include/cache.h b/src/include/cache.h
index 456cb0382e4..0a42853b95b 100644
--- a/src/include/cache.h
+++ b/src/include/cache.h
@@ -152,20 +152,28 @@ struct __wt_cache {
 #define	WT_EVICT_SCORE_BUMP	10
 #define	WT_EVICT_SCORE_CUTOFF	10
 #define	WT_EVICT_SCORE_MAX	100
-	uint32_t evict_aggressive_score;/* Score of how aggressive eviction
-					   should be about selecting eviction
-					   candidates. If eviction is
-					   struggling to make progress, this
-					   score rises (up to a maximum of
-					   100), at which point the cache is
-					   "stuck" and transaction will be
-					   rolled back. */
-	uint32_t evict_empty_score;	/* Score of how often LRU queues are
-					   empty on refill. This score varies
-					   between 0 (if the queue hasn't been
-					   empty for a long time) and 100 (if
-					   the queue has been empty the last 10
-					   times we filled up. */
+	/*
+	 * Score of how aggressive eviction should be about selecting eviction
+	 * candidates. If eviction is struggling to make progress, this score
+	 * rises (up to a maximum of 100), at which point the cache is "stuck"
+	 * and transaction will be rolled back.
+	 */
+	uint32_t evict_aggressive_score;
+
+	/*
+	 * Score of how often LRU queues are empty on refill. This score varies
+	 * between 0 (if the queue hasn't been empty for a long time) and 100
+	 * (if the queue has been empty the last 10 times we filled up.
+	 */
+	uint32_t evict_empty_score;
+
+	/*
+	 * Score of how much pressure storing historical versions is having on
+	 * eviction.  This score varies between 0, if reconciliation always
+	 * sees updates that are globally visible and hence can be discarded,
+	 * to 100 if no updates are globally visible.
+	 */
+	int32_t evict_lookaside_score;
 
 	/*
 	 * Cache pool information.
diff --git a/src/include/cache.i b/src/include/cache.i
index 33b1bf2a7af..e160dbf4d64 100644
--- a/src/include/cache.i
+++ b/src/include/cache.i
@@ -79,22 +79,6 @@ __wt_cache_read_gen_new(WT_SESSION_IMPL *session, WT_PAGE *page)
 }
 
 /*
- * __wt_cache_nearly_stuck --
- *      Indicate if the cache is nearly stuck.
- */
-static inline bool
-__wt_cache_nearly_stuck(WT_SESSION_IMPL *session)
-{
-	WT_CACHE *cache;
-
-	cache = S2C(session)->cache;
-	return (cache->evict_aggressive_score >=
-	    (WT_EVICT_SCORE_MAX - WT_EVICT_SCORE_BUMP) &&
-	    F_ISSET(cache,
-		WT_CACHE_EVICT_CLEAN_HARD | WT_CACHE_EVICT_DIRTY_HARD));
-}
-
-/*
  * __wt_cache_stuck --
  *      Indicate if the cache is stuck (i.e., not making progress).
  */
@@ -205,6 +189,43 @@ __wt_cache_bytes_other(WT_CACHE *cache)
 }
 
 /*
+ * __wt_cache_lookaside_score --
+ *	Get the current lookaside score (between 0 and 100).
+ */
+static inline uint32_t
+__wt_cache_lookaside_score(WT_CACHE *cache)
+{
+	int32_t global_score;
+
+	global_score = cache->evict_lookaside_score;
+	return ((uint32_t)WT_MIN(WT_MAX(global_score, 0), 100));
+}
+
+/*
+ * __wt_cache_update_lookaside_score --
+ *	Update the lookaside score based how many unstable updates are seen.
+ */
+static inline void
+__wt_cache_update_lookaside_score(
+	WT_SESSION_IMPL *session, u_int updates_seen, u_int updates_unstable)
+{
+	WT_CACHE *cache;
+	int32_t global_score, score;
+
+	if (updates_seen == 0)
+		return;
+
+	cache = S2C(session)->cache;
+	score = (int32_t)((100 * updates_unstable) / updates_seen);
+	global_score = cache->evict_lookaside_score;
+
+	if (score > global_score && global_score < 100)
+		__wt_atomic_addi32(&cache->evict_lookaside_score, 1);
+	else if (score < global_score && global_score > 0)
+		__wt_atomic_subi32(&cache->evict_lookaside_score, 1);
+}
+
+/*
  * __wt_session_can_wait --
  *	Return if a session available for a potentially slow operation.
  */
diff --git a/src/include/stat.h b/src/include/stat.h
index 922b211bec4..12a7d532496 100644
--- a/src/include/stat.h
+++ b/src/include/stat.h
@@ -341,6 +341,7 @@ struct __wt_connection_stats {
 	int64_t cache_eviction_internal;
 	int64_t cache_eviction_split_internal;
 	int64_t cache_eviction_split_leaf;
+	int64_t cache_lookaside_score;
 	int64_t cache_lookaside_entries;
 	int64_t cache_lookaside_insert;
 	int64_t cache_lookaside_remove;
diff --git a/src/include/wiredtiger.in b/src/include/wiredtiger.in
index aeea3394015..41dd970d3ba 100644
--- a/src/include/wiredtiger.in
+++ b/src/include/wiredtiger.in
@@ -4854,456 +4854,458 @@ extern int wiredtiger_extension_terminate(WT_CONNECTION *connection);
 #define	WT_STAT_CONN_CACHE_EVICTION_SPLIT_INTERNAL	1082
 /*! cache: leaf pages split during eviction */
 #define	WT_STAT_CONN_CACHE_EVICTION_SPLIT_LEAF		1083
+/*! cache: lookaside score */
+#define	WT_STAT_CONN_CACHE_LOOKASIDE_SCORE		1084
 /*! cache: lookaside table entries */
-#define	WT_STAT_CONN_CACHE_LOOKASIDE_ENTRIES		1084
+#define	WT_STAT_CONN_CACHE_LOOKASIDE_ENTRIES		1085
 /*! cache: lookaside table insert calls */
-#define	WT_STAT_CONN_CACHE_LOOKASIDE_INSERT		1085
+#define	WT_STAT_CONN_CACHE_LOOKASIDE_INSERT		1086
 /*! cache: lookaside table remove calls */
-#define	WT_STAT_CONN_CACHE_LOOKASIDE_REMOVE		1086
+#define	WT_STAT_CONN_CACHE_LOOKASIDE_REMOVE		1087
 /*! cache: maximum bytes configured */
-#define	WT_STAT_CONN_CACHE_BYTES_MAX			1087
+#define	WT_STAT_CONN_CACHE_BYTES_MAX			1088
 /*! cache: maximum page size at eviction */
-#define	WT_STAT_CONN_CACHE_EVICTION_MAXIMUM_PAGE_SIZE	1088
+#define	WT_STAT_CONN_CACHE_EVICTION_MAXIMUM_PAGE_SIZE	1089
 /*! cache: modified pages evicted */
-#define	WT_STAT_CONN_CACHE_EVICTION_DIRTY		1089
+#define	WT_STAT_CONN_CACHE_EVICTION_DIRTY		1090
 /*! cache: modified pages evicted by application threads */
-#define	WT_STAT_CONN_CACHE_EVICTION_APP_DIRTY		1090
+#define	WT_STAT_CONN_CACHE_EVICTION_APP_DIRTY		1091
 /*! cache: overflow pages read into cache */
-#define	WT_STAT_CONN_CACHE_READ_OVERFLOW		1091
+#define	WT_STAT_CONN_CACHE_READ_OVERFLOW		1092
 /*! cache: page split during eviction deepened the tree */
-#define	WT_STAT_CONN_CACHE_EVICTION_DEEPEN		1092
+#define	WT_STAT_CONN_CACHE_EVICTION_DEEPEN		1093
 /*! cache: page written requiring lookaside records */
-#define	WT_STAT_CONN_CACHE_WRITE_LOOKASIDE		1093
+#define	WT_STAT_CONN_CACHE_WRITE_LOOKASIDE		1094
 /*! cache: pages currently held in the cache */
-#define	WT_STAT_CONN_CACHE_PAGES_INUSE			1094
+#define	WT_STAT_CONN_CACHE_PAGES_INUSE			1095
 /*! cache: pages evicted because they exceeded the in-memory maximum count */
-#define	WT_STAT_CONN_CACHE_EVICTION_FORCE		1095
+#define	WT_STAT_CONN_CACHE_EVICTION_FORCE		1096
 /*!
  * cache: pages evicted because they exceeded the in-memory maximum time
  * (usecs)
  */
-#define	WT_STAT_CONN_CACHE_EVICTION_FORCE_TIME		1096
+#define	WT_STAT_CONN_CACHE_EVICTION_FORCE_TIME		1097
 /*! cache: pages evicted because they had chains of deleted items count */
-#define	WT_STAT_CONN_CACHE_EVICTION_FORCE_DELETE	1097
+#define	WT_STAT_CONN_CACHE_EVICTION_FORCE_DELETE	1098
 /*!
  * cache: pages evicted because they had chains of deleted items time
  * (usecs)
  */
-#define	WT_STAT_CONN_CACHE_EVICTION_FORCE_DELETE_TIME	1098
+#define	WT_STAT_CONN_CACHE_EVICTION_FORCE_DELETE_TIME	1099
 /*! cache: pages evicted by application threads */
-#define	WT_STAT_CONN_CACHE_EVICTION_APP			1099
+#define	WT_STAT_CONN_CACHE_EVICTION_APP			1100
 /*! cache: pages queued for eviction */
-#define	WT_STAT_CONN_CACHE_EVICTION_PAGES_QUEUED	1100
+#define	WT_STAT_CONN_CACHE_EVICTION_PAGES_QUEUED	1101
 /*! cache: pages queued for urgent eviction */
-#define	WT_STAT_CONN_CACHE_EVICTION_PAGES_QUEUED_URGENT	1101
+#define	WT_STAT_CONN_CACHE_EVICTION_PAGES_QUEUED_URGENT	1102
 /*! cache: pages queued for urgent eviction during walk */
-#define	WT_STAT_CONN_CACHE_EVICTION_PAGES_QUEUED_OLDEST	1102
+#define	WT_STAT_CONN_CACHE_EVICTION_PAGES_QUEUED_OLDEST	1103
 /*! cache: pages read into cache */
-#define	WT_STAT_CONN_CACHE_READ				1103
+#define	WT_STAT_CONN_CACHE_READ				1104
 /*! cache: pages read into cache requiring lookaside entries */
-#define	WT_STAT_CONN_CACHE_READ_LOOKASIDE		1104
+#define	WT_STAT_CONN_CACHE_READ_LOOKASIDE		1105
 /*! cache: pages requested from the cache */
-#define	WT_STAT_CONN_CACHE_PAGES_REQUESTED		1105
+#define	WT_STAT_CONN_CACHE_PAGES_REQUESTED		1106
 /*! cache: pages seen by eviction walk */
-#define	WT_STAT_CONN_CACHE_EVICTION_PAGES_SEEN		1106
+#define	WT_STAT_CONN_CACHE_EVICTION_PAGES_SEEN		1107
 /*! cache: pages selected for eviction unable to be evicted */
-#define	WT_STAT_CONN_CACHE_EVICTION_FAIL		1107
+#define	WT_STAT_CONN_CACHE_EVICTION_FAIL		1108
 /*! cache: pages walked for eviction */
-#define	WT_STAT_CONN_CACHE_EVICTION_WALK		1108
+#define	WT_STAT_CONN_CACHE_EVICTION_WALK		1109
 /*! cache: pages written from cache */
-#define	WT_STAT_CONN_CACHE_WRITE			1109
+#define	WT_STAT_CONN_CACHE_WRITE			1110
 /*! cache: pages written requiring in-memory restoration */
-#define	WT_STAT_CONN_CACHE_WRITE_RESTORE		1110
+#define	WT_STAT_CONN_CACHE_WRITE_RESTORE		1111
 /*! cache: percentage overhead */
-#define	WT_STAT_CONN_CACHE_OVERHEAD			1111
+#define	WT_STAT_CONN_CACHE_OVERHEAD			1112
 /*! cache: tracked bytes belonging to internal pages in the cache */
-#define	WT_STAT_CONN_CACHE_BYTES_INTERNAL		1112
+#define	WT_STAT_CONN_CACHE_BYTES_INTERNAL		1113
 /*! cache: tracked bytes belonging to leaf pages in the cache */
-#define	WT_STAT_CONN_CACHE_BYTES_LEAF			1113
+#define	WT_STAT_CONN_CACHE_BYTES_LEAF			1114
 /*! cache: tracked dirty bytes in the cache */
-#define	WT_STAT_CONN_CACHE_BYTES_DIRTY			1114
+#define	WT_STAT_CONN_CACHE_BYTES_DIRTY			1115
 /*! cache: tracked dirty pages in the cache */
-#define	WT_STAT_CONN_CACHE_PAGES_DIRTY			1115
+#define	WT_STAT_CONN_CACHE_PAGES_DIRTY			1116
 /*! cache: unmodified pages evicted */
-#define	WT_STAT_CONN_CACHE_EVICTION_CLEAN		1116
+#define	WT_STAT_CONN_CACHE_EVICTION_CLEAN		1117
 /*! connection: auto adjusting condition resets */
-#define	WT_STAT_CONN_COND_AUTO_WAIT_RESET		1117
+#define	WT_STAT_CONN_COND_AUTO_WAIT_RESET		1118
 /*! connection: auto adjusting condition wait calls */
-#define	WT_STAT_CONN_COND_AUTO_WAIT			1118
+#define	WT_STAT_CONN_COND_AUTO_WAIT			1119
 /*! connection: detected system time went backwards */
-#define	WT_STAT_CONN_TIME_TRAVEL			1119
+#define	WT_STAT_CONN_TIME_TRAVEL			1120
 /*! connection: files currently open */
-#define	WT_STAT_CONN_FILE_OPEN				1120
+#define	WT_STAT_CONN_FILE_OPEN				1121
 /*! connection: memory allocations */
-#define	WT_STAT_CONN_MEMORY_ALLOCATION			1121
+#define	WT_STAT_CONN_MEMORY_ALLOCATION			1122
 /*! connection: memory frees */
-#define	WT_STAT_CONN_MEMORY_FREE			1122
+#define	WT_STAT_CONN_MEMORY_FREE			1123
 /*! connection: memory re-allocations */
-#define	WT_STAT_CONN_MEMORY_GROW			1123
+#define	WT_STAT_CONN_MEMORY_GROW			1124
 /*! connection: pthread mutex condition wait calls */
-#define	WT_STAT_CONN_COND_WAIT				1124
+#define	WT_STAT_CONN_COND_WAIT				1125
 /*! connection: pthread mutex shared lock read-lock calls */
-#define	WT_STAT_CONN_RWLOCK_READ			1125
+#define	WT_STAT_CONN_RWLOCK_READ			1126
 /*! connection: pthread mutex shared lock write-lock calls */
-#define	WT_STAT_CONN_RWLOCK_WRITE			1126
+#define	WT_STAT_CONN_RWLOCK_WRITE			1127
 /*! connection: total fsync I/Os */
-#define	WT_STAT_CONN_FSYNC_IO				1127
+#define	WT_STAT_CONN_FSYNC_IO				1128
 /*! connection: total read I/Os */
-#define	WT_STAT_CONN_READ_IO				1128
+#define	WT_STAT_CONN_READ_IO				1129
 /*! connection: total write I/Os */
-#define	WT_STAT_CONN_WRITE_IO				1129
+#define	WT_STAT_CONN_WRITE_IO				1130
 /*! cursor: cursor create calls */
-#define	WT_STAT_CONN_CURSOR_CREATE			1130
+#define	WT_STAT_CONN_CURSOR_CREATE			1131
 /*! cursor: cursor insert calls */
-#define	WT_STAT_CONN_CURSOR_INSERT			1131
+#define	WT_STAT_CONN_CURSOR_INSERT			1132
 /*! cursor: cursor modify calls */
-#define	WT_STAT_CONN_CURSOR_MODIFY			1132
+#define	WT_STAT_CONN_CURSOR_MODIFY			1133
 /*! cursor: cursor next calls */
-#define	WT_STAT_CONN_CURSOR_NEXT			1133
+#define	WT_STAT_CONN_CURSOR_NEXT			1134
 /*! cursor: cursor prev calls */
-#define	WT_STAT_CONN_CURSOR_PREV			1134
+#define	WT_STAT_CONN_CURSOR_PREV			1135
 /*! cursor: cursor remove calls */
-#define	WT_STAT_CONN_CURSOR_REMOVE			1135
+#define	WT_STAT_CONN_CURSOR_REMOVE			1136
 /*! cursor: cursor reserve calls */
-#define	WT_STAT_CONN_CURSOR_RESERVE			1136
+#define	WT_STAT_CONN_CURSOR_RESERVE			1137
 /*! cursor: cursor reset calls */
-#define	WT_STAT_CONN_CURSOR_RESET			1137
+#define	WT_STAT_CONN_CURSOR_RESET			1138
 /*! cursor: cursor restarted searches */
-#define	WT_STAT_CONN_CURSOR_RESTART			1138
+#define	WT_STAT_CONN_CURSOR_RESTART			1139
 /*! cursor: cursor search calls */
-#define	WT_STAT_CONN_CURSOR_SEARCH			1139
+#define	WT_STAT_CONN_CURSOR_SEARCH			1140
 /*! cursor: cursor search near calls */
-#define	WT_STAT_CONN_CURSOR_SEARCH_NEAR			1140
+#define	WT_STAT_CONN_CURSOR_SEARCH_NEAR			1141
 /*! cursor: cursor update calls */
-#define	WT_STAT_CONN_CURSOR_UPDATE			1141
+#define	WT_STAT_CONN_CURSOR_UPDATE			1142
 /*! cursor: truncate calls */
-#define	WT_STAT_CONN_CURSOR_TRUNCATE			1142
+#define	WT_STAT_CONN_CURSOR_TRUNCATE			1143
 /*! data-handle: connection data handles currently active */
-#define	WT_STAT_CONN_DH_CONN_HANDLE_COUNT		1143
+#define	WT_STAT_CONN_DH_CONN_HANDLE_COUNT		1144
 /*! data-handle: connection sweep candidate became referenced */
-#define	WT_STAT_CONN_DH_SWEEP_REF			1144
+#define	WT_STAT_CONN_DH_SWEEP_REF			1145
 /*! data-handle: connection sweep dhandles closed */
-#define	WT_STAT_CONN_DH_SWEEP_CLOSE			1145
+#define	WT_STAT_CONN_DH_SWEEP_CLOSE			1146
 /*! data-handle: connection sweep dhandles removed from hash list */
-#define	WT_STAT_CONN_DH_SWEEP_REMOVE			1146
+#define	WT_STAT_CONN_DH_SWEEP_REMOVE			1147
 /*! data-handle: connection sweep time-of-death sets */
-#define	WT_STAT_CONN_DH_SWEEP_TOD			1147
+#define	WT_STAT_CONN_DH_SWEEP_TOD			1148
 /*! data-handle: connection sweeps */
-#define	WT_STAT_CONN_DH_SWEEPS				1148
+#define	WT_STAT_CONN_DH_SWEEPS				1149
 /*! data-handle: session dhandles swept */
-#define	WT_STAT_CONN_DH_SESSION_HANDLES			1149
+#define	WT_STAT_CONN_DH_SESSION_HANDLES			1150
 /*! data-handle: session sweep attempts */
-#define	WT_STAT_CONN_DH_SESSION_SWEEPS			1150
+#define	WT_STAT_CONN_DH_SESSION_SWEEPS			1151
 /*! lock: checkpoint lock acquisitions */
-#define	WT_STAT_CONN_LOCK_CHECKPOINT_COUNT		1151
+#define	WT_STAT_CONN_LOCK_CHECKPOINT_COUNT		1152
 /*! lock: checkpoint lock application thread wait time (usecs) */
-#define	WT_STAT_CONN_LOCK_CHECKPOINT_WAIT_APPLICATION	1152
+#define	WT_STAT_CONN_LOCK_CHECKPOINT_WAIT_APPLICATION	1153
 /*! lock: checkpoint lock internal thread wait time (usecs) */
-#define	WT_STAT_CONN_LOCK_CHECKPOINT_WAIT_INTERNAL	1153
+#define	WT_STAT_CONN_LOCK_CHECKPOINT_WAIT_INTERNAL	1154
 /*!
  * lock: dhandle lock application thread time waiting for the dhandle
  * lock (usecs)
  */
-#define	WT_STAT_CONN_LOCK_DHANDLE_WAIT_APPLICATION	1154
+#define	WT_STAT_CONN_LOCK_DHANDLE_WAIT_APPLICATION	1155
 /*!
  * lock: dhandle lock internal thread time waiting for the dhandle lock
  * (usecs)
  */
-#define	WT_STAT_CONN_LOCK_DHANDLE_WAIT_INTERNAL		1155
+#define	WT_STAT_CONN_LOCK_DHANDLE_WAIT_INTERNAL		1156
 /*! lock: dhandle read lock acquisitions */
-#define	WT_STAT_CONN_LOCK_DHANDLE_READ_COUNT		1156
+#define	WT_STAT_CONN_LOCK_DHANDLE_READ_COUNT		1157
 /*! lock: dhandle write lock acquisitions */
-#define	WT_STAT_CONN_LOCK_DHANDLE_WRITE_COUNT		1157
+#define	WT_STAT_CONN_LOCK_DHANDLE_WRITE_COUNT		1158
 /*! lock: metadata lock acquisitions */
-#define	WT_STAT_CONN_LOCK_METADATA_COUNT		1158
+#define	WT_STAT_CONN_LOCK_METADATA_COUNT		1159
 /*! lock: metadata lock application thread wait time (usecs) */
-#define	WT_STAT_CONN_LOCK_METADATA_WAIT_APPLICATION	1159
+#define	WT_STAT_CONN_LOCK_METADATA_WAIT_APPLICATION	1160
 /*! lock: metadata lock internal thread wait time (usecs) */
-#define	WT_STAT_CONN_LOCK_METADATA_WAIT_INTERNAL	1160
+#define	WT_STAT_CONN_LOCK_METADATA_WAIT_INTERNAL	1161
 /*! lock: schema lock acquisitions */
-#define	WT_STAT_CONN_LOCK_SCHEMA_COUNT			1161
+#define	WT_STAT_CONN_LOCK_SCHEMA_COUNT			1162
 /*! lock: schema lock application thread wait time (usecs) */
-#define	WT_STAT_CONN_LOCK_SCHEMA_WAIT_APPLICATION	1162
+#define	WT_STAT_CONN_LOCK_SCHEMA_WAIT_APPLICATION	1163
 /*! lock: schema lock internal thread wait time (usecs) */
-#define	WT_STAT_CONN_LOCK_SCHEMA_WAIT_INTERNAL		1163
+#define	WT_STAT_CONN_LOCK_SCHEMA_WAIT_INTERNAL		1164
 /*!
  * lock: table lock application thread time waiting for the table lock
  * (usecs)
  */
-#define	WT_STAT_CONN_LOCK_TABLE_WAIT_APPLICATION	1164
+#define	WT_STAT_CONN_LOCK_TABLE_WAIT_APPLICATION	1165
 /*!
  * lock: table lock internal thread time waiting for the table lock
  * (usecs)
  */
-#define	WT_STAT_CONN_LOCK_TABLE_WAIT_INTERNAL		1165
+#define	WT_STAT_CONN_LOCK_TABLE_WAIT_INTERNAL		1166
 /*! lock: table read lock acquisitions */
-#define	WT_STAT_CONN_LOCK_TABLE_READ_COUNT		1166
+#define	WT_STAT_CONN_LOCK_TABLE_READ_COUNT		1167
 /*! lock: table write lock acquisitions */
-#define	WT_STAT_CONN_LOCK_TABLE_WRITE_COUNT		1167
+#define	WT_STAT_CONN_LOCK_TABLE_WRITE_COUNT		1168
 /*! log: busy returns attempting to switch slots */
-#define	WT_STAT_CONN_LOG_SLOT_SWITCH_BUSY		1168
+#define	WT_STAT_CONN_LOG_SLOT_SWITCH_BUSY		1169
 /*! log: force checkpoint calls slept */
-#define	WT_STAT_CONN_LOG_FORCE_CKPT_SLEEP		1169
+#define	WT_STAT_CONN_LOG_FORCE_CKPT_SLEEP		1170
 /*! log: log bytes of payload data */
-#define	WT_STAT_CONN_LOG_BYTES_PAYLOAD			1170
+#define	WT_STAT_CONN_LOG_BYTES_PAYLOAD			1171
 /*! log: log bytes written */
-#define	WT_STAT_CONN_LOG_BYTES_WRITTEN			1171
+#define	WT_STAT_CONN_LOG_BYTES_WRITTEN			1172
 /*! log: log files manually zero-filled */
-#define	WT_STAT_CONN_LOG_ZERO_FILLS			1172
+#define	WT_STAT_CONN_LOG_ZERO_FILLS			1173
 /*! log: log flush operations */
-#define	WT_STAT_CONN_LOG_FLUSH				1173
+#define	WT_STAT_CONN_LOG_FLUSH				1174
 /*! log: log force write operations */
-#define	WT_STAT_CONN_LOG_FORCE_WRITE			1174
+#define	WT_STAT_CONN_LOG_FORCE_WRITE			1175
 /*! log: log force write operations skipped */
-#define	WT_STAT_CONN_LOG_FORCE_WRITE_SKIP		1175
+#define	WT_STAT_CONN_LOG_FORCE_WRITE_SKIP		1176
 /*! log: log records compressed */
-#define	WT_STAT_CONN_LOG_COMPRESS_WRITES		1176
+#define	WT_STAT_CONN_LOG_COMPRESS_WRITES		1177
 /*! log: log records not compressed */
-#define	WT_STAT_CONN_LOG_COMPRESS_WRITE_FAILS		1177
+#define	WT_STAT_CONN_LOG_COMPRESS_WRITE_FAILS		1178
 /*! log: log records too small to compress */
-#define	WT_STAT_CONN_LOG_COMPRESS_SMALL			1178
+#define	WT_STAT_CONN_LOG_COMPRESS_SMALL			1179
 /*! log: log release advances write LSN */
-#define	WT_STAT_CONN_LOG_RELEASE_WRITE_LSN		1179
+#define	WT_STAT_CONN_LOG_RELEASE_WRITE_LSN		1180
 /*! log: log scan operations */
-#define	WT_STAT_CONN_LOG_SCANS				1180
+#define	WT_STAT_CONN_LOG_SCANS				1181
 /*! log: log scan records requiring two reads */
-#define	WT_STAT_CONN_LOG_SCAN_REREADS			1181
+#define	WT_STAT_CONN_LOG_SCAN_REREADS			1182
 /*! log: log server thread advances write LSN */
-#define	WT_STAT_CONN_LOG_WRITE_LSN			1182
+#define	WT_STAT_CONN_LOG_WRITE_LSN			1183
 /*! log: log server thread write LSN walk skipped */
-#define	WT_STAT_CONN_LOG_WRITE_LSN_SKIP			1183
+#define	WT_STAT_CONN_LOG_WRITE_LSN_SKIP			1184
 /*! log: log sync operations */
-#define	WT_STAT_CONN_LOG_SYNC				1184
+#define	WT_STAT_CONN_LOG_SYNC				1185
 /*! log: log sync time duration (usecs) */
-#define	WT_STAT_CONN_LOG_SYNC_DURATION			1185
+#define	WT_STAT_CONN_LOG_SYNC_DURATION			1186
 /*! log: log sync_dir operations */
-#define	WT_STAT_CONN_LOG_SYNC_DIR			1186
+#define	WT_STAT_CONN_LOG_SYNC_DIR			1187
 /*! log: log sync_dir time duration (usecs) */
-#define	WT_STAT_CONN_LOG_SYNC_DIR_DURATION		1187
+#define	WT_STAT_CONN_LOG_SYNC_DIR_DURATION		1188
 /*! log: log write operations */
-#define	WT_STAT_CONN_LOG_WRITES				1188
+#define	WT_STAT_CONN_LOG_WRITES				1189
 /*! log: logging bytes consolidated */
-#define	WT_STAT_CONN_LOG_SLOT_CONSOLIDATED		1189
+#define	WT_STAT_CONN_LOG_SLOT_CONSOLIDATED		1190
 /*! log: maximum log file size */
-#define	WT_STAT_CONN_LOG_MAX_FILESIZE			1190
+#define	WT_STAT_CONN_LOG_MAX_FILESIZE			1191
 /*! log: number of pre-allocated log files to create */
-#define	WT_STAT_CONN_LOG_PREALLOC_MAX			1191
+#define	WT_STAT_CONN_LOG_PREALLOC_MAX			1192
 /*! log: pre-allocated log files not ready and missed */
-#define	WT_STAT_CONN_LOG_PREALLOC_MISSED		1192
+#define	WT_STAT_CONN_LOG_PREALLOC_MISSED		1193
 /*! log: pre-allocated log files prepared */
-#define	WT_STAT_CONN_LOG_PREALLOC_FILES			1193
+#define	WT_STAT_CONN_LOG_PREALLOC_FILES			1194
 /*! log: pre-allocated log files used */
-#define	WT_STAT_CONN_LOG_PREALLOC_USED			1194
+#define	WT_STAT_CONN_LOG_PREALLOC_USED			1195
 /*! log: records processed by log scan */
-#define	WT_STAT_CONN_LOG_SCAN_RECORDS			1195
+#define	WT_STAT_CONN_LOG_SCAN_RECORDS			1196
 /*! log: slot close lost race */
-#define	WT_STAT_CONN_LOG_SLOT_CLOSE_RACE		1196
+#define	WT_STAT_CONN_LOG_SLOT_CLOSE_RACE		1197
 /*! log: slot close unbuffered waits */
-#define	WT_STAT_CONN_LOG_SLOT_CLOSE_UNBUF		1197
+#define	WT_STAT_CONN_LOG_SLOT_CLOSE_UNBUF		1198
 /*! log: slot closures */
-#define	WT_STAT_CONN_LOG_SLOT_CLOSES			1198
+#define	WT_STAT_CONN_LOG_SLOT_CLOSES			1199
 /*! log: slot join atomic update races */
-#define	WT_STAT_CONN_LOG_SLOT_RACES			1199
+#define	WT_STAT_CONN_LOG_SLOT_RACES			1200
 /*! log: slot join calls atomic updates raced */
-#define	WT_STAT_CONN_LOG_SLOT_YIELD_RACE		1200
+#define	WT_STAT_CONN_LOG_SLOT_YIELD_RACE		1201
 /*! log: slot join calls did not yield */
-#define	WT_STAT_CONN_LOG_SLOT_IMMEDIATE			1201
+#define	WT_STAT_CONN_LOG_SLOT_IMMEDIATE			1202
 /*! log: slot join calls found active slot closed */
-#define	WT_STAT_CONN_LOG_SLOT_YIELD_CLOSE		1202
+#define	WT_STAT_CONN_LOG_SLOT_YIELD_CLOSE		1203
 /*! log: slot join calls slept */
-#define	WT_STAT_CONN_LOG_SLOT_YIELD_SLEEP		1203
+#define	WT_STAT_CONN_LOG_SLOT_YIELD_SLEEP		1204
 /*! log: slot join calls yielded */
-#define	WT_STAT_CONN_LOG_SLOT_YIELD			1204
+#define	WT_STAT_CONN_LOG_SLOT_YIELD			1205
 /*! log: slot join found active slot closed */
-#define	WT_STAT_CONN_LOG_SLOT_ACTIVE_CLOSED		1205
+#define	WT_STAT_CONN_LOG_SLOT_ACTIVE_CLOSED		1206
 /*! log: slot joins yield time (usecs) */
-#define	WT_STAT_CONN_LOG_SLOT_YIELD_DURATION		1206
+#define	WT_STAT_CONN_LOG_SLOT_YIELD_DURATION		1207
 /*! log: slot transitions unable to find free slot */
-#define	WT_STAT_CONN_LOG_SLOT_NO_FREE_SLOTS		1207
+#define	WT_STAT_CONN_LOG_SLOT_NO_FREE_SLOTS		1208
 /*! log: slot unbuffered writes */
-#define	WT_STAT_CONN_LOG_SLOT_UNBUFFERED		1208
+#define	WT_STAT_CONN_LOG_SLOT_UNBUFFERED		1209
 /*! log: total in-memory size of compressed records */
-#define	WT_STAT_CONN_LOG_COMPRESS_MEM			1209
+#define	WT_STAT_CONN_LOG_COMPRESS_MEM			1210
 /*! log: total log buffer size */
-#define	WT_STAT_CONN_LOG_BUFFER_SIZE			1210
+#define	WT_STAT_CONN_LOG_BUFFER_SIZE			1211
 /*! log: total size of compressed records */
-#define	WT_STAT_CONN_LOG_COMPRESS_LEN			1211
+#define	WT_STAT_CONN_LOG_COMPRESS_LEN			1212
 /*! log: written slots coalesced */
-#define	WT_STAT_CONN_LOG_SLOT_COALESCED			1212
+#define	WT_STAT_CONN_LOG_SLOT_COALESCED			1213
 /*! log: yields waiting for previous log file close */
-#define	WT_STAT_CONN_LOG_CLOSE_YIELDS			1213
+#define	WT_STAT_CONN_LOG_CLOSE_YIELDS			1214
 /*! reconciliation: fast-path pages deleted */
-#define	WT_STAT_CONN_REC_PAGE_DELETE_FAST		1214
+#define	WT_STAT_CONN_REC_PAGE_DELETE_FAST		1215
 /*! reconciliation: page reconciliation calls */
-#define	WT_STAT_CONN_REC_PAGES				1215
+#define	WT_STAT_CONN_REC_PAGES				1216
 /*! reconciliation: page reconciliation calls for eviction */
-#define	WT_STAT_CONN_REC_PAGES_EVICTION			1216
+#define	WT_STAT_CONN_REC_PAGES_EVICTION			1217
 /*! reconciliation: pages deleted */
-#define	WT_STAT_CONN_REC_PAGE_DELETE			1217
+#define	WT_STAT_CONN_REC_PAGE_DELETE			1218
 /*! reconciliation: split bytes currently awaiting free */
-#define	WT_STAT_CONN_REC_SPLIT_STASHED_BYTES		1218
+#define	WT_STAT_CONN_REC_SPLIT_STASHED_BYTES		1219
 /*! reconciliation: split objects currently awaiting free */
-#define	WT_STAT_CONN_REC_SPLIT_STASHED_OBJECTS		1219
+#define	WT_STAT_CONN_REC_SPLIT_STASHED_OBJECTS		1220
 /*! session: open cursor count */
-#define	WT_STAT_CONN_SESSION_CURSOR_OPEN		1220
+#define	WT_STAT_CONN_SESSION_CURSOR_OPEN		1221
 /*! session: open session count */
-#define	WT_STAT_CONN_SESSION_OPEN			1221
+#define	WT_STAT_CONN_SESSION_OPEN			1222
 /*! session: table alter failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_ALTER_FAIL		1222
+#define	WT_STAT_CONN_SESSION_TABLE_ALTER_FAIL		1223
 /*! session: table alter successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_ALTER_SUCCESS	1223
+#define	WT_STAT_CONN_SESSION_TABLE_ALTER_SUCCESS	1224
 /*! session: table alter unchanged and skipped */
-#define	WT_STAT_CONN_SESSION_TABLE_ALTER_SKIP		1224
+#define	WT_STAT_CONN_SESSION_TABLE_ALTER_SKIP		1225
 /*! session: table compact failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_COMPACT_FAIL		1225
+#define	WT_STAT_CONN_SESSION_TABLE_COMPACT_FAIL		1226
 /*! session: table compact successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_COMPACT_SUCCESS	1226
+#define	WT_STAT_CONN_SESSION_TABLE_COMPACT_SUCCESS	1227
 /*! session: table create failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_CREATE_FAIL		1227
+#define	WT_STAT_CONN_SESSION_TABLE_CREATE_FAIL		1228
 /*! session: table create successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_CREATE_SUCCESS	1228
+#define	WT_STAT_CONN_SESSION_TABLE_CREATE_SUCCESS	1229
 /*! session: table drop failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_DROP_FAIL		1229
+#define	WT_STAT_CONN_SESSION_TABLE_DROP_FAIL		1230
 /*! session: table drop successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_DROP_SUCCESS		1230
+#define	WT_STAT_CONN_SESSION_TABLE_DROP_SUCCESS		1231
 /*! session: table rebalance failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_REBALANCE_FAIL	1231
+#define	WT_STAT_CONN_SESSION_TABLE_REBALANCE_FAIL	1232
 /*! session: table rebalance successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_REBALANCE_SUCCESS	1232
+#define	WT_STAT_CONN_SESSION_TABLE_REBALANCE_SUCCESS	1233
 /*! session: table rename failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_RENAME_FAIL		1233
+#define	WT_STAT_CONN_SESSION_TABLE_RENAME_FAIL		1234
 /*! session: table rename successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_RENAME_SUCCESS	1234
+#define	WT_STAT_CONN_SESSION_TABLE_RENAME_SUCCESS	1235
 /*! session: table salvage failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_SALVAGE_FAIL		1235
+#define	WT_STAT_CONN_SESSION_TABLE_SALVAGE_FAIL		1236
 /*! session: table salvage successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_SALVAGE_SUCCESS	1236
+#define	WT_STAT_CONN_SESSION_TABLE_SALVAGE_SUCCESS	1237
 /*! session: table truncate failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_TRUNCATE_FAIL	1237
+#define	WT_STAT_CONN_SESSION_TABLE_TRUNCATE_FAIL	1238
 /*! session: table truncate successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_TRUNCATE_SUCCESS	1238
+#define	WT_STAT_CONN_SESSION_TABLE_TRUNCATE_SUCCESS	1239
 /*! session: table verify failed calls */
-#define	WT_STAT_CONN_SESSION_TABLE_VERIFY_FAIL		1239
+#define	WT_STAT_CONN_SESSION_TABLE_VERIFY_FAIL		1240
 /*! session: table verify successful calls */
-#define	WT_STAT_CONN_SESSION_TABLE_VERIFY_SUCCESS	1240
+#define	WT_STAT_CONN_SESSION_TABLE_VERIFY_SUCCESS	1241
 /*! thread-state: active filesystem fsync calls */
-#define	WT_STAT_CONN_THREAD_FSYNC_ACTIVE		1241
+#define	WT_STAT_CONN_THREAD_FSYNC_ACTIVE		1242
 /*! thread-state: active filesystem read calls */
-#define	WT_STAT_CONN_THREAD_READ_ACTIVE			1242
+#define	WT_STAT_CONN_THREAD_READ_ACTIVE			1243
 /*! thread-state: active filesystem write calls */
-#define	WT_STAT_CONN_THREAD_WRITE_ACTIVE		1243
+#define	WT_STAT_CONN_THREAD_WRITE_ACTIVE		1244
 /*! thread-yield: application thread time evicting (usecs) */
-#define	WT_STAT_CONN_APPLICATION_EVICT_TIME		1244
+#define	WT_STAT_CONN_APPLICATION_EVICT_TIME		1245
 /*! thread-yield: application thread time waiting for cache (usecs) */
-#define	WT_STAT_CONN_APPLICATION_CACHE_TIME		1245
+#define	WT_STAT_CONN_APPLICATION_CACHE_TIME		1246
 /*!
  * thread-yield: connection close blocked waiting for transaction state
  * stabilization
  */
-#define	WT_STAT_CONN_TXN_RELEASE_BLOCKED		1246
+#define	WT_STAT_CONN_TXN_RELEASE_BLOCKED		1247
 /*! thread-yield: connection close yielded for lsm manager shutdown */
-#define	WT_STAT_CONN_CONN_CLOSE_BLOCKED_LSM		1247
+#define	WT_STAT_CONN_CONN_CLOSE_BLOCKED_LSM		1248
 /*! thread-yield: data handle lock yielded */
-#define	WT_STAT_CONN_DHANDLE_LOCK_BLOCKED		1248
+#define	WT_STAT_CONN_DHANDLE_LOCK_BLOCKED		1249
 /*!
  * thread-yield: get reference for page index and slot time sleeping
  * (usecs)
  */
-#define	WT_STAT_CONN_PAGE_INDEX_SLOT_REF_BLOCKED	1249
+#define	WT_STAT_CONN_PAGE_INDEX_SLOT_REF_BLOCKED	1250
 /*! thread-yield: log server sync yielded for log write */
-#define	WT_STAT_CONN_LOG_SERVER_SYNC_BLOCKED		1250
+#define	WT_STAT_CONN_LOG_SERVER_SYNC_BLOCKED		1251
 /*! thread-yield: page acquire busy blocked */
-#define	WT_STAT_CONN_PAGE_BUSY_BLOCKED			1251
+#define	WT_STAT_CONN_PAGE_BUSY_BLOCKED			1252
 /*! thread-yield: page acquire eviction blocked */
-#define	WT_STAT_CONN_PAGE_FORCIBLE_EVICT_BLOCKED	1252
+#define	WT_STAT_CONN_PAGE_FORCIBLE_EVICT_BLOCKED	1253
 /*! thread-yield: page acquire locked blocked */
-#define	WT_STAT_CONN_PAGE_LOCKED_BLOCKED		1253
+#define	WT_STAT_CONN_PAGE_LOCKED_BLOCKED		1254
 /*! thread-yield: page acquire read blocked */
-#define	WT_STAT_CONN_PAGE_READ_BLOCKED			1254
+#define	WT_STAT_CONN_PAGE_READ_BLOCKED			1255
 /*! thread-yield: page acquire time sleeping (usecs) */
-#define	WT_STAT_CONN_PAGE_SLEEP				1255
+#define	WT_STAT_CONN_PAGE_SLEEP				1256
 /*!
  * thread-yield: page delete rollback time sleeping for state change
  * (usecs)
  */
-#define	WT_STAT_CONN_PAGE_DEL_ROLLBACK_BLOCKED		1256
+#define	WT_STAT_CONN_PAGE_DEL_ROLLBACK_BLOCKED		1257
 /*! thread-yield: page reconciliation yielded due to child modification */
-#define	WT_STAT_CONN_CHILD_MODIFY_BLOCKED_PAGE		1257
+#define	WT_STAT_CONN_CHILD_MODIFY_BLOCKED_PAGE		1258
 /*!
  * thread-yield: tree descend one level yielded for split page index
  * update
  */
-#define	WT_STAT_CONN_TREE_DESCEND_BLOCKED		1258
+#define	WT_STAT_CONN_TREE_DESCEND_BLOCKED		1259
 /*! transaction: number of named snapshots created */
-#define	WT_STAT_CONN_TXN_SNAPSHOTS_CREATED		1259
+#define	WT_STAT_CONN_TXN_SNAPSHOTS_CREATED		1260
 /*! transaction: number of named snapshots dropped */
-#define	WT_STAT_CONN_TXN_SNAPSHOTS_DROPPED		1260
+#define	WT_STAT_CONN_TXN_SNAPSHOTS_DROPPED		1261
 /*! transaction: transaction begins */
-#define	WT_STAT_CONN_TXN_BEGIN				1261
+#define	WT_STAT_CONN_TXN_BEGIN				1262
 /*! transaction: transaction checkpoint currently running */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_RUNNING		1262
+#define	WT_STAT_CONN_TXN_CHECKPOINT_RUNNING		1263
 /*! transaction: transaction checkpoint generation */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_GENERATION		1263
+#define	WT_STAT_CONN_TXN_CHECKPOINT_GENERATION		1264
 /*! transaction: transaction checkpoint max time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_MAX		1264
+#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_MAX		1265
 /*! transaction: transaction checkpoint min time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_MIN		1265
+#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_MIN		1266
 /*! transaction: transaction checkpoint most recent time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_RECENT		1266
+#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_RECENT		1267
 /*! transaction: transaction checkpoint scrub dirty target */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_SCRUB_TARGET	1267
+#define	WT_STAT_CONN_TXN_CHECKPOINT_SCRUB_TARGET	1268
 /*! transaction: transaction checkpoint scrub time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_SCRUB_TIME		1268
+#define	WT_STAT_CONN_TXN_CHECKPOINT_SCRUB_TIME		1269
 /*! transaction: transaction checkpoint total time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_TOTAL		1269
+#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_TOTAL		1270
 /*! transaction: transaction checkpoints */
-#define	WT_STAT_CONN_TXN_CHECKPOINT			1270
+#define	WT_STAT_CONN_TXN_CHECKPOINT			1271
 /*!
  * transaction: transaction checkpoints skipped because database was
  * clean
  */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_SKIPPED		1271
+#define	WT_STAT_CONN_TXN_CHECKPOINT_SKIPPED		1272
 /*! transaction: transaction failures due to cache overflow */
-#define	WT_STAT_CONN_TXN_FAIL_CACHE			1272
+#define	WT_STAT_CONN_TXN_FAIL_CACHE			1273
 /*!
  * transaction: transaction fsync calls for checkpoint after allocating
  * the transaction ID
  */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_FSYNC_POST		1273
+#define	WT_STAT_CONN_TXN_CHECKPOINT_FSYNC_POST		1274
 /*!
  * transaction: transaction fsync duration for checkpoint after
  * allocating the transaction ID (usecs)
  */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_FSYNC_POST_DURATION	1274
+#define	WT_STAT_CONN_TXN_CHECKPOINT_FSYNC_POST_DURATION	1275
 /*! transaction: transaction range of IDs currently pinned */
-#define	WT_STAT_CONN_TXN_PINNED_RANGE			1275
+#define	WT_STAT_CONN_TXN_PINNED_RANGE			1276
 /*! transaction: transaction range of IDs currently pinned by a checkpoint */
-#define	WT_STAT_CONN_TXN_PINNED_CHECKPOINT_RANGE	1276
+#define	WT_STAT_CONN_TXN_PINNED_CHECKPOINT_RANGE	1277
 /*!
  * transaction: transaction range of IDs currently pinned by named
  * snapshots
  */
-#define	WT_STAT_CONN_TXN_PINNED_SNAPSHOT_RANGE		1277
+#define	WT_STAT_CONN_TXN_PINNED_SNAPSHOT_RANGE		1278
 /*! transaction: transaction sync calls */
-#define	WT_STAT_CONN_TXN_SYNC				1278
+#define	WT_STAT_CONN_TXN_SYNC				1279
 /*! transaction: transactions commit timestamp queue inserts to head */
-#define	WT_STAT_CONN_TXN_COMMIT_QUEUE_HEAD		1279
+#define	WT_STAT_CONN_TXN_COMMIT_QUEUE_HEAD		1280
 /*! transaction: transactions commit timestamp queue inserts total */
-#define	WT_STAT_CONN_TXN_COMMIT_QUEUE_INSERTS		1280
+#define	WT_STAT_CONN_TXN_COMMIT_QUEUE_INSERTS		1281
 /*! transaction: transactions commit timestamp queue length */
-#define	WT_STAT_CONN_TXN_COMMIT_QUEUE_LEN		1281
+#define	WT_STAT_CONN_TXN_COMMIT_QUEUE_LEN		1282
 /*! transaction: transactions committed */
-#define	WT_STAT_CONN_TXN_COMMIT				1282
+#define	WT_STAT_CONN_TXN_COMMIT				1283
 /*! transaction: transactions read timestamp queue inserts to head */
-#define	WT_STAT_CONN_TXN_READ_QUEUE_HEAD		1283
+#define	WT_STAT_CONN_TXN_READ_QUEUE_HEAD		1284
 /*! transaction: transactions read timestamp queue inserts total */
-#define	WT_STAT_CONN_TXN_READ_QUEUE_INSERTS		1284
+#define	WT_STAT_CONN_TXN_READ_QUEUE_INSERTS		1285
 /*! transaction: transactions read timestamp queue length */
-#define	WT_STAT_CONN_TXN_READ_QUEUE_LEN			1285
+#define	WT_STAT_CONN_TXN_READ_QUEUE_LEN			1286
 /*! transaction: transactions rolled back */
-#define	WT_STAT_CONN_TXN_ROLLBACK			1286
+#define	WT_STAT_CONN_TXN_ROLLBACK			1287
 /*! transaction: update conflicts */
-#define	WT_STAT_CONN_TXN_UPDATE_CONFLICT		1287
+#define	WT_STAT_CONN_TXN_UPDATE_CONFLICT		1288
 
 /*!
  * @}
diff --git a/src/reconcile/rec_write.c b/src/reconcile/rec_write.c
index ae856649ede..c3e0cb20ec1 100644
--- a/src/reconcile/rec_write.c
+++ b/src/reconcile/rec_write.c
@@ -50,6 +50,9 @@ typedef struct {
 	WT_DECL_TIMESTAMP(max_timestamp)
 	WT_DECL_TIMESTAMP(min_saved_timestamp)
 
+	u_int updates_seen;		/* Count of updates seen. */
+	u_int updates_unstable;		/* Count of updates not visible_all. */
+
 	bool update_uncommitted;	/* An update was uncommitted */
 	bool update_used;		/* An update could be used */
 
@@ -450,6 +453,15 @@ __wt_reconcile(WT_SESSION_IMPL *session, WT_REF *ref,
 	WT_ILLEGAL_VALUE_SET(session);
 	}
 
+	/*
+	 * Update the global lookaside score.  Only use observations during
+	 * eviction, not checkpoints and don't count eviction of the lookaside
+	 * table itself.
+	 */
+	if (F_ISSET(r, WT_REC_EVICT) && !F_ISSET(btree, WT_BTREE_LOOKASIDE))
+		__wt_cache_update_lookaside_score(
+		    session, r->updates_seen, r->updates_unstable);
+
 	/* Check for a successful reconciliation. */
 	WT_TRET(__rec_write_check_complete(session, r, ret, lookaside_retryp));
 
@@ -970,6 +982,7 @@ __rec_init(WT_SESSION_IMPL *session,
 #endif
 
 	/* Track if updates were used and/or uncommitted. */
+	r->updates_seen = r->updates_unstable = 0;
 	r->update_uncommitted = r->update_used = false;
 
 	/* Track if the page can be marked clean. */
@@ -1255,6 +1268,7 @@ __rec_txn_read(WT_SESSION_IMPL *session, WT_RECONCILE *r,
 		if ((txnid = upd->txnid) == WT_TXN_ABORTED)
 			continue;
 
+		++r->updates_seen;
 		upd_memsize += WT_UPDATE_MEMSIZE(upd);
 
 		/*
@@ -1297,10 +1311,28 @@ __rec_txn_read(WT_SESSION_IMPL *session, WT_RECONCILE *r,
 		 * uncommitted updates).  Lookaside eviction can save any
 		 * committed update.  Regular eviction checks that the maximum
 		 * transaction ID and timestamp seen are stable.
+		 *
+		 * Lookaside eviction tries to choose the same version as a
+		 * subsequent checkpoint, so that checkpoint can skip over
+		 * pages with lookaside entries.  If the application has
+		 * supplied a stable timestamp, we assume (a) that it is old,
+		 * and (b) that the next checkpoint will use it, so we wait to
+		 * see a stable update.  If there is no stable timestamp, we
+		 * assume the next checkpoint will write the most recent
+		 * version (but we save enough information that checkpoint can
+		 * fix things up if we choose an update that is too new).
 		 */
+		if (*updp == NULL && F_ISSET(r, WT_REC_LOOKASIDE) &&
+		    F_ISSET(r, WT_REC_VISIBLE_ALL) &&
+		    !S2C(session)->txn_global.has_stable_timestamp)
+			*updp = upd;
+
 		if (F_ISSET(r, WT_REC_VISIBLE_ALL) ?
 		    !__wt_txn_upd_visible_all(session, upd) :
 		    !__wt_txn_upd_visible(session, upd)) {
+			if (F_ISSET(r, WT_REC_EVICT))
+				++r->updates_unstable;
+
 			/*
 			 * Rare case: when applications run at low isolation
 			 * levels, update/restore eviction may see a stable
@@ -1441,12 +1473,14 @@ check_original_value:
 	/*
 	 * Returning an update means the original on-page value might be lost,
 	 * and that's a problem if there's a reader that needs it. There are
-	 * two cases: any lookaside table eviction (because the backing disk
-	 * image is rewritten), or any reconciliation of a backing overflow
-	 * record that will be physically removed once it's no longer needed.
-	 */
-	if (*updp != NULL && (F_ISSET(r, WT_REC_LOOKASIDE) ||
-	    (vpack != NULL &&
+	 * three cases: any update from a modify operation (because the modify
+	 * has to be applied to a stable update, not the new on-page update),
+	 * any lookaside table eviction (because the backing disk image is
+	 * rewritten), or any reconciliation of a backing overflow record that
+	 * will be physically removed once it's no longer needed.
+	 */
+	if (*updp != NULL && ((*updp)->type == WT_UPDATE_MODIFIED ||
+	    F_ISSET(r, WT_REC_LOOKASIDE) || (vpack != NULL &&
 	    vpack->ovfl && vpack->raw != WT_CELL_VALUE_OVFL_RM)))
 		WT_RET(
 		    __rec_append_orig_value(session, page, first_upd, vpack));
@@ -3301,6 +3335,12 @@ __rec_split_write_supd(WT_SESSION_IMPL *session,
 		r->supd_next = j;
 	}
 
+	/* Track the oldest timestamp seen so far. */
+#ifdef HAVE_TIMESTAMPS
+	multi->las_max_txn = r->max_txn;
+	__wt_timestamp_set(&multi->las_min_timestamp, &r->min_saved_timestamp);
+#endif
+
 err:	__wt_scr_free(session, &key);
 	return (ret);
 }
@@ -5870,6 +5910,7 @@ __rec_write_wrapup(WT_SESSION_IMPL *session, WT_RECONCILE *r, WT_PAGE *page)
 			mod->mod_disk_image = r->multi->disk_image;
 			r->multi->disk_image = NULL;
 			mod->mod_replace_las_pageid = r->multi->las_pageid;
+			mod->mod_replace_las_max_txn = r->max_txn;
 #ifdef HAVE_TIMESTAMPS
 			__wt_timestamp_set(&mod->mod_replace_las_min_timestamp,
 			     &r->min_saved_timestamp);
diff --git a/src/support/stat.c b/src/support/stat.c
index 57dcd33c7f1..924afaa21d6 100644
--- a/src/support/stat.c
+++ b/src/support/stat.c
@@ -809,6 +809,7 @@ static const char * const __stats_connection_desc[] = {
 	"cache: internal pages evicted",
 	"cache: internal pages split during eviction",
 	"cache: leaf pages split during eviction",
+	"cache: lookaside score",
 	"cache: lookaside table entries",
 	"cache: lookaside table insert calls",
 	"cache: lookaside table remove calls",
@@ -1139,6 +1140,7 @@ __wt_stat_connection_clear_single(WT_CONNECTION_STATS *stats)
 	stats->cache_eviction_internal = 0;
 	stats->cache_eviction_split_internal = 0;
 	stats->cache_eviction_split_leaf = 0;
+		/* not clearing cache_lookaside_score */
 		/* not clearing cache_lookaside_entries */
 	stats->cache_lookaside_insert = 0;
 	stats->cache_lookaside_remove = 0;
@@ -1490,6 +1492,8 @@ __wt_stat_connection_aggregate(
 	    WT_STAT_READ(from, cache_eviction_split_internal);
 	to->cache_eviction_split_leaf +=
 	    WT_STAT_READ(from, cache_eviction_split_leaf);
+	to->cache_lookaside_score +=
+	    WT_STAT_READ(from, cache_lookaside_score);
 	to->cache_lookaside_entries +=
 	    WT_STAT_READ(from, cache_lookaside_entries);
 	to->cache_lookaside_insert +=