Import wiredtiger: 3a63ddcbed28c5f40ef026c55b85e34042a9715d from branch mongodb-3.6r3.6.19-rc0r3.6.19

ref: 723a4c1329..3a63ddcbed
for: 3.6.19

WT-5119       Birthmark records can be read as normal updates if reads race with checkpoints
WT-5150       LAS sweep is not removing the entries that are no longer required
WT-5196       Data mismatch failures with test/checkpoint after enabling LAS sweep
WT-5376       WT_UPDATE.type field can race with visibility checks when returning key/value pairs
WT-5587       Limit how many checkpoints are dropped by a subsequent checkpoint

5 files changed, 61 insertions, 47 deletions

diff --git a/src/third_party/wiredtiger/import.data b/src/third_party/wiredtiger/import.data
index ae855e43736..6ba8cf0167c 100644
--- a/src/third_party/wiredtiger/import.data
+++ b/src/third_party/wiredtiger/import.data
@@ -2,5 +2,5 @@
     "vendor": "wiredtiger",
     "github": "wiredtiger/wiredtiger.git",
     "branch": "mongodb-3.6",
-    "commit": "723a4c13292b0bc7e27be411db4d006a0b865bd8"
+    "commit": "3a63ddcbed28c5f40ef026c55b85e34042a9715d"
 }
diff --git a/src/third_party/wiredtiger/src/cache/cache_las.c b/src/third_party/wiredtiger/src/cache/cache_las.c
index 35a76210a0c..07791e38942 100644
--- a/src/third_party/wiredtiger/src/cache/cache_las.c
+++ b/src/third_party/wiredtiger/src/cache/cache_las.c
@@ -1035,11 +1035,8 @@ __las_sweep_init(WT_SESSION_IMPL *session)
 	 * If no files have been dropped and the lookaside file is empty,
 	 * there's nothing to do.
 	 */
-	if (cache->las_dropped_next == 0) {
-		if (__wt_las_empty(session))
-			ret = WT_NOTFOUND;
-		goto err;
-	}
+	if (cache->las_dropped_next == 0 && __wt_las_empty(session))
+		WT_ERR(WT_NOTFOUND);
 
 	/*
 	 * Record the current page ID: sweep will stop after this point.
@@ -1093,7 +1090,6 @@ __wt_las_sweep(WT_SESSION_IMPL *session)
 	WT_DECL_RET;
 	WT_ITEM las_key, las_timestamp, las_value;
 	WT_ITEM *sweep_key;
-	WT_TXN_ISOLATION saved_isolation;
 #ifdef HAVE_TIMESTAMPS
 	wt_timestamp_t timestamp, *val_ts;
 #else
@@ -1128,7 +1124,6 @@ __wt_las_sweep(WT_SESSION_IMPL *session)
 	 */
 	__wt_las_cursor(session, &cursor, &session_flags);
 	WT_ASSERT(session, cursor->session == &session->iface);
-	__las_set_isolation(session, &saved_isolation);
 	WT_ERR(__wt_txn_begin(session, NULL));
 	local_txn = true;
 
@@ -1323,7 +1318,6 @@ err:		__wt_buf_free(session, sweep_key);
 			    &cache->las_remove_count, remove_cnt);
 	}
 
-	__las_restore_isolation(session, saved_isolation);
 	WT_TRET(__wt_las_cursor_close(session, &cursor, session_flags));
 
 	if (locked)
diff --git a/src/third_party/wiredtiger/src/include/txn.i b/src/third_party/wiredtiger/src/include/txn.i
index 7010af975c1..816d7693901 100644
--- a/src/third_party/wiredtiger/src/include/txn.i
+++ b/src/third_party/wiredtiger/src/include/txn.i
@@ -784,32 +784,39 @@ __wt_txn_upd_visible(WT_SESSION_IMPL *session, WT_UPDATE *upd)
 static inline int
 __wt_txn_read(WT_SESSION_IMPL *session, WT_UPDATE *upd, WT_UPDATE **updp)
 {
-	static WT_UPDATE tombstone = {
+    static WT_UPDATE tombstone = {
 		.txnid = WT_TXN_NONE, .type = WT_UPDATE_TOMBSTONE
 	};
-	WT_VISIBLE_TYPE upd_visible;
-	bool skipped_birthmark;
-
-	*updp = NULL;
-	for (skipped_birthmark = false; upd != NULL; upd = upd->next) {
-		/* Skip reserved place-holders, they're never visible. */
-		if (upd->type != WT_UPDATE_RESERVE) {
-			upd_visible = __wt_txn_upd_visible_type(session, upd);
-			if (upd_visible == WT_VISIBLE_TRUE)
-				break;
-			if (upd_visible == WT_VISIBLE_PREPARE)
-				return (WT_PREPARE_CONFLICT);
-		}
-		/* An invisible birthmark is equivalent to a tombstone. */
-		if (upd->type == WT_UPDATE_BIRTHMARK)
-			skipped_birthmark = true;
+    WT_VISIBLE_TYPE upd_visible;
+    uint8_t type;
+    bool skipped_birthmark;
+
+    *updp = NULL;
+
+    type = WT_UPDATE_INVALID; /* [-Wconditional-uninitialized] */
+    for (skipped_birthmark = false; upd != NULL; upd = upd->next) {
+	WT_ORDERED_READ(type, upd->type);
+
+	/* Skip reserved place-holders, they're never visible. */
+	if (type != WT_UPDATE_RESERVE) {
+	    upd_visible = __wt_txn_upd_visible_type(session, upd);
+	    if (upd_visible == WT_VISIBLE_TRUE)
+		break;
+	    if (upd_visible == WT_VISIBLE_PREPARE)
+		return (WT_PREPARE_CONFLICT);
 	}
-
-	if (upd == NULL && skipped_birthmark)
-		upd = &tombstone;
-
-	*updp = upd == NULL || upd->type == WT_UPDATE_BIRTHMARK ? NULL : upd;
-	return (0);
+	/* An invisible birthmark is equivalent to a tombstone. */
+	if (type == WT_UPDATE_BIRTHMARK)
+	    skipped_birthmark = true;
+    }
+
+    if (upd == NULL && skipped_birthmark) {
+	upd = &tombstone;
+	type = upd->type;
+    }
+
+    *updp = upd == NULL || type == WT_UPDATE_BIRTHMARK ? NULL : upd;
+    return (0);
 }
 
 /*
diff --git a/src/third_party/wiredtiger/src/reconcile/rec_write.c b/src/third_party/wiredtiger/src/reconcile/rec_write.c
index 5821292f454..d8632dc6742 100644
--- a/src/third_party/wiredtiger/src/reconcile/rec_write.c
+++ b/src/third_party/wiredtiger/src/reconcile/rec_write.c
@@ -1347,8 +1347,8 @@ __rec_append_orig_value(WT_SESSION_IMPL *session,
 	__wt_cache_page_inmem_incr(session, page, size);
 
 	if (upd->type == WT_UPDATE_BIRTHMARK) {
-		upd->type = WT_UPDATE_STANDARD;
-		upd->txnid = WT_TXN_ABORTED;
+		WT_PUBLISH(upd->txnid, WT_TXN_ABORTED);
+		WT_PUBLISH(upd->type, WT_UPDATE_STANDARD);
 	}
 
 err:	__wt_scr_free(session, &tmp);
diff --git a/src/third_party/wiredtiger/src/txn/txn_ckpt.c b/src/third_party/wiredtiger/src/txn/txn_ckpt.c
index dd00ff7d36a..dcea60b135a 100644
--- a/src/third_party/wiredtiger/src/txn/txn_ckpt.c
+++ b/src/third_party/wiredtiger/src/txn/txn_ckpt.c
@@ -1205,23 +1205,36 @@ __wt_txn_checkpoint(WT_SESSION_IMPL *session, const char *cfg[], bool waiting)
 static void
 __drop(WT_CKPT *ckptbase, const char *name, size_t len)
 {
-	WT_CKPT *ckpt;
+    WT_CKPT *ckpt;
+    u_int max_ckpt_drop;
 
-	/*
-	 * If we're dropping internal checkpoints, match to the '.' separating
+    /*
+     * If we're dropping internal checkpoints, match to the '.' separating
 	 * the checkpoint name from the generational number, and take all that
 	 * we can find.  Applications aren't allowed to use any variant of this
 	 * name, so the test is still pretty simple, if the leading bytes match,
-	 * it's one we want to drop.
-	 */
-	if (strncmp(WT_CHECKPOINT, name, len) == 0) {
-		WT_CKPT_FOREACH(ckptbase, ckpt)
-			if (WT_PREFIX_MATCH(ckpt->name, WT_CHECKPOINT))
-				F_SET(ckpt, WT_CKPT_DELETE);
-	} else
-		WT_CKPT_FOREACH(ckptbase, ckpt)
-			if (WT_STRING_MATCH(ckpt->name, name, len))
-				F_SET(ckpt, WT_CKPT_DELETE);
+     * it's one we want to drop.
+     */
+    if (strncmp(WT_CHECKPOINT, name, len) == 0) {
+	/*
+	 * Currently, hot backup cursors block checkpoint drop, which means
+	 * releasing a hot backup cursor can result in immediately attempting
+	 * to drop lots of checkpoints, which involves a fair amount of work
+	 * while holding locks. Limit the number of standard checkpoints dropped
+	 * per checkpoint.
+	 */
+	max_ckpt_drop = 0;
+	WT_CKPT_FOREACH (ckptbase, ckpt)
+	    if (WT_PREFIX_MATCH(ckpt->name, WT_CHECKPOINT)) {
+		F_SET(ckpt, WT_CKPT_DELETE);
+#define	WT_MAX_CHECKPOINT_DROP 4
+		if (++max_ckpt_drop >= WT_MAX_CHECKPOINT_DROP)
+		    break;
+	    }
+    } else
+	WT_CKPT_FOREACH (ckptbase, ckpt)
+	    if (WT_STRING_MATCH(ckpt->name, name, len))
+		F_SET(ckpt, WT_CKPT_DELETE);
 }
 
 /*