Import wiredtiger: b055251678e6b4fcc74a1f651432aadbfeecc0e4 from branch mongodb-3.6

ref: 698847557c..b055251678
for: 3.5.12

WT-3328       Enhance docs around when schema operations can get EBUSY
WT-3358       LSM will hang if the manager fails to start
WT-3365       Understand how timestamps interact with LSM chunk switching
WT-3399       Add new checkpoint blocking test case to automated testing
WT-3417       Drain transactions during upgrade/downgrade.
WT-3441       test_timestamp01 doesn't account for a large WT_TIMESTAMP_SIZE
WT-3450       Add verbose option that tracks timestamp state and information
WT-3452       Enhance existing recovery test to exercise timestamp API
WT-3455       Enhance eviction to be aware of stable timestamp
WT-3459       Test WiredTiger with clock shifting
WT-3460       Add support for rollback_to_stable to column store
WT-3465       Optimize performance when timestamp size is 8 bytes
WT-3483       WT_SESSION::checkpoint returning WT_ROLLBACK
WT-3492       ex_all.c not calling transaction_ops
WT-3493       wt_verbose_dump_txn should display timestamp information
WT-3497       Improve logging message when hitting the WT session limits
WT-3498       Incorrect data read after caching overflow items
WT-3499       Checkpoint can miss not yet committed item
WT-3500       New timestamp-abort test is too chatty
WT-3502       Only keep 10 delta updates between full copies
WT-3503       Coverity 1379333: unchecked return value, full-build Friday
WT-3508       timestamp-abort bug in verification phase
WT-3509       __wt_illegal_value doesn't always provide a failure location
WT-3514       WT_SESSION.checkpoint: read timestamp 6373c older than oldest timestamp
WT-3517       WT_SESSION::reset doesn't need to call out EBUSY specially
WT-3521       Unstable updates should not be written by lookaside eviction

1 files changed, 3 insertions, 1 deletions

diff --git a/src/third_party/wiredtiger/src/include/txn.h b/src/third_party/wiredtiger/src/include/txn.h
index 61ab343151c..e0513a82892 100644
--- a/src/third_party/wiredtiger/src/include/txn.h
+++ b/src/third_party/wiredtiger/src/include/txn.h
@@ -69,7 +69,6 @@ struct __wt_named_snapshot {
 
 struct __wt_txn_state {
 	WT_CACHE_LINE_PAD_BEGIN
-	WT_RWLOCK rwlock;
 	volatile uint64_t id;
 	volatile uint64_t pinned_id;
 	volatile uint64_t metadata_pinned;
@@ -105,6 +104,9 @@ struct __wt_txn_global {
 	/* Protects the active transaction states. */
 	WT_RWLOCK rwlock;
 
+	/* Protects logging, checkpoints and transaction visibility. */
+	WT_RWLOCK visibility_rwlock;
+
 	/* List of transactions sorted by commit timestamp. */
 	WT_RWLOCK commit_timestamp_rwlock;
 	TAILQ_HEAD(__wt_txn_cts_qh, __wt_txn) commit_timestamph;