Import wiredtiger: 0cd3d5bbd8a5c8779f1129c6754b4463403e788f from branch mongodb-3.6

ref: 6f561957cb..0cd3d5bbd8
for: 3.5.14

WT-3200       LSM bug: Failed lookup in bloom filter.
WT-3435       Lookaside eviction should be able to save unstable updates
WT-3453       Enhance lookaside table test coverage in Python suite
WT-3559       Detect when a checkpoint races with metadata changes
WT-3579       Enhance support for running wtperf workloads with workgen
WT-3582       Cache stuck full of internal pages
WT-3593       Add an API to enforce consistent use of timestamps (#3667)
WT-3599       reconciliation calculates block matching checksums too frequently.
WT-3600       timestamp API lets you set timestamps with invalid characters
WT-3612       Improve documentation of durability with backup cursors
WT-3613       test/format cache full with LSM
WT-3618       WT remove solaris from evergreen builds
WT-3620       POSIX thread attribute structures must be destroyed
WT-3621       Add test for full backups with concurrent table creation
WT-3622       Allow upper case hexadecimal timestamps
WT-3627       test_txn14.test_txn14.test_log_flush timeout
WT-3631       Convert timestamps to integers in Python tests before comparing
WT-3636       Account for page image sizes in cache consistently
WT-3638       format failure, update list without complete visible record
WT-3639       Test/format tried to drop named checkpoints during a hot backup
WT-3641       Track maximum timestamp used in each btree
WT-3642       Avoid lookaside reads for dead trees

3 files changed, 12 insertions, 6 deletions

diff --git a/src/third_party/wiredtiger/src/docs/backup.dox b/src/third_party/wiredtiger/src/docs/backup.dox
index 91b15da9275..b952a975788 100644
--- a/src/third_party/wiredtiger/src/docs/backup.dox
+++ b/src/third_party/wiredtiger/src/docs/backup.dox
@@ -59,10 +59,12 @@ During the period the backup cursor is open, database checkpoints can
 be created, but no checkpoints can be deleted.  This may result in
 significant file growth.
 
-Additionally, if a crash occurs during the period the backup cursor is open and
-logging is disabled, then the system will be restored to the most recent
-checkpoint prior to the opening of the backup cursor, even if later database
-checkpoints were created.
+Additionally, if a crash occurs during the period the backup cursor is
+open and logging is disabled (in other words, when depending on
+checkpoints for durability), then the system will be restored to the
+most recent checkpoint prior to the opening of the backup cursor, even
+if later database checkpoints were completed. <b>Note this exception to
+WiredTiger's checkpoint durability guarantees.</b>
 
 The following is a programmatic example of creating a backup:
 
diff --git a/src/third_party/wiredtiger/src/docs/checkpoint.dox b/src/third_party/wiredtiger/src/docs/checkpoint.dox
index ec28fea13c3..3d636cd17b6 100644
--- a/src/third_party/wiredtiger/src/docs/checkpoint.dox
+++ b/src/third_party/wiredtiger/src/docs/checkpoint.dox
@@ -22,6 +22,10 @@ configuration to ::wiredtiger_open.
 All transactional updates committed before a checkpoint are made durable
 by the checkpoint, therefore the frequency of checkpoints limits the
 volume of data that may be lost due to application or system failure.
+<b>This guarantee has an exception:</b> If a crash occurs when a backup
+cursor is open, then the system will be restored to the most recent
+checkpoint prior to the opening of the backup cursor, even if later
+database checkpoints were completed.
 
 Data sources that are involved in an exclusive operation when the
 checkpoint starts, including bulk load, verify or salvage, will be skipped
diff --git a/src/third_party/wiredtiger/src/docs/transactions.dox b/src/third_party/wiredtiger/src/docs/transactions.dox
index d9cc72dcf24..4ba6d5d2526 100644
--- a/src/third_party/wiredtiger/src/docs/transactions.dox
+++ b/src/third_party/wiredtiger/src/docs/transactions.dox
@@ -165,8 +165,8 @@ transaction timestamp functionality.
 
 Applications can assign explicit commit timestamps to transactions, then read
 "as of" a timestamp.  Timestamps are communicated to WiredTiger using a
-lower case hexadecimal encoding, so the encoded value can be twice as long as
-the raw timestamp value.
+hexadecimal encoding, so the encoded value can be twice as long as the raw
+timestamp value.
 
 Setting a read timestamp in WT_SESSION::begin_transaction forces a transaction
 to run at snapshot isolation and ignore any commits with a newer timestamp.