Import wiredtiger: 3cff49bd4b5585b563cbb1fba272b5ce28cd8660 from branch mongodb-4.4

ref: 9b7e4a5cc4..3cff49bd4b
for: 4.4.24

WT-8539 Correct description for statistic for rolling back oldest pinned.

6 files changed, 66 insertions, 66 deletions

diff --git a/src/third_party/wiredtiger/dist/stat_data.py b/src/third_party/wiredtiger/dist/stat_data.py
index f95c85ed06a..125087f6189 100644
--- a/src/third_party/wiredtiger/dist/stat_data.py
+++ b/src/third_party/wiredtiger/dist/stat_data.py
@@ -537,7 +537,6 @@ conn_stats = [
     TxnStat('txn_checkpoint_handle_duration', 'transaction checkpoint most recent duration for gathering all handles (usecs)', 'no_clear,no_scale'),
     TxnStat('txn_checkpoint_handle_duration_apply', 'transaction checkpoint most recent duration for gathering applied handles (usecs)', 'no_clear,no_scale'),
     TxnStat('txn_checkpoint_handle_duration_skip', 'transaction checkpoint most recent duration for gathering skipped handles (usecs)', 'no_clear,no_scale'),
-    TxnStat('txn_hs_ckpt_duration', 'transaction checkpoint history store file duration (usecs)'),
     TxnStat('txn_checkpoint_generation', 'transaction checkpoint generation', 'no_clear,no_scale'),
     TxnStat('txn_checkpoint_prep_max', 'transaction checkpoint prepare max time (msecs)', 'no_clear,no_scale'),
     TxnStat('txn_checkpoint_prep_min', 'transaction checkpoint prepare min time (msecs)', 'no_clear,no_scale'),
@@ -555,7 +554,7 @@ conn_stats = [
     TxnStat('txn_checkpoint_time_total', 'transaction checkpoint total time (msecs)', 'no_clear,no_scale'),
     TxnStat('txn_checkpoint_stop_stress_active', 'transaction checkpoint stop timing stress active', 'no_clear,no_scale'),
     TxnStat('txn_commit', 'transactions committed'),
-    TxnStat('txn_fail_cache', 'transaction failures due to history store'),
+    TxnStat('txn_hs_ckpt_duration', 'transaction checkpoint history store file duration (usecs)'),
     TxnStat('txn_pinned_checkpoint_range', 'transaction range of IDs currently pinned by a checkpoint', 'no_clear,no_scale'),
     TxnStat('txn_pinned_range', 'transaction range of IDs currently pinned', 'no_clear,no_scale'),
     TxnStat('txn_pinned_timestamp', 'transaction range of timestamps currently pinned', 'no_clear,no_scale'),
@@ -574,6 +573,7 @@ conn_stats = [
     TxnStat('txn_prepared_updates_rolledback', 'Number of prepared updates rolled back'),
     TxnStat('txn_query_ts', 'query timestamp calls'),
     TxnStat('txn_rollback', 'transactions rolled back'),
+    TxnStat('txn_rollback_oldest_pinned', 'oldest pinned transaction ID rolled back for eviction'),
     TxnStat('txn_rollback_to_stable_running', 'transaction rollback to stable currently running', 'no_clear,no_scale'),
     TxnStat('txn_rts', 'rollback to stable calls'),
     TxnStat('txn_rts_pages_visited', 'rollback to stable pages visited'),
diff --git a/src/third_party/wiredtiger/import.data b/src/third_party/wiredtiger/import.data
index 706a3b3d3d0..4c1e49ae4fc 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-4.4",
-    "commit": "9b7e4a5cc49aec602e3e5c26d92b985265f286f8"
+    "commit": "3cff49bd4b5585b563cbb1fba272b5ce28cd8660"
 }
diff --git a/src/third_party/wiredtiger/src/evict/evict_lru.c b/src/third_party/wiredtiger/src/evict/evict_lru.c
index 0bfaf1c9f33..0eaf532ac60 100644
--- a/src/third_party/wiredtiger/src/evict/evict_lru.c
+++ b/src/third_party/wiredtiger/src/evict/evict_lru.c
@@ -2384,7 +2384,7 @@ __wt_cache_eviction_worker(WT_SESSION_IMPL *session, bool busy, bool readonly, d
             ret = __wt_txn_is_blocking(session);
             if (ret == WT_ROLLBACK) {
                 --cache->evict_aggressive_score;
-                WT_STAT_CONN_INCR(session, txn_fail_cache);
+                WT_STAT_CONN_INCR(session, txn_rollback_oldest_pinned);
                 if (app_thread)
                     WT_TRET(__wt_msg(session, "%s", session->txn->rollback_reason));
             }
diff --git a/src/third_party/wiredtiger/src/include/stat.h b/src/third_party/wiredtiger/src/include/stat.h
index b6224c04a9d..db91dfc7ce4 100644
--- a/src/third_party/wiredtiger/src/include/stat.h
+++ b/src/third_party/wiredtiger/src/include/stat.h
@@ -743,6 +743,7 @@ struct __wt_connection_stats {
     int64_t txn_prepared_updates_committed;
     int64_t txn_prepared_updates_key_repeated;
     int64_t txn_prepared_updates_rolledback;
+    int64_t txn_rollback_oldest_pinned;
     int64_t txn_prepare;
     int64_t txn_prepare_commit;
     int64_t txn_prepare_active;
@@ -799,7 +800,6 @@ struct __wt_connection_stats {
     int64_t txn_checkpoint;
     int64_t txn_checkpoint_obsolete_applied;
     int64_t txn_checkpoint_skipped;
-    int64_t txn_fail_cache;
     int64_t txn_checkpoint_fsync_post;
     int64_t txn_checkpoint_fsync_post_duration;
     int64_t txn_pinned_range;
diff --git a/src/third_party/wiredtiger/src/include/wiredtiger.in b/src/third_party/wiredtiger/src/include/wiredtiger.in
index 0f837b559b7..ce8f39a2ce7 100644
--- a/src/third_party/wiredtiger/src/include/wiredtiger.in
+++ b/src/third_party/wiredtiger/src/include/wiredtiger.in
@@ -6075,147 +6075,147 @@ extern int wiredtiger_extension_terminate(WT_CONNECTION *connection);
 #define	WT_STAT_CONN_TXN_PREPARED_UPDATES_KEY_REPEATED	1428
 /*! transaction: Number of prepared updates rolled back */
 #define	WT_STAT_CONN_TXN_PREPARED_UPDATES_ROLLEDBACK	1429
+/*! transaction: oldest pinned transaction ID rolled back for eviction */
+#define	WT_STAT_CONN_TXN_ROLLBACK_OLDEST_PINNED		1430
 /*! transaction: prepared transactions */
-#define	WT_STAT_CONN_TXN_PREPARE			1430
+#define	WT_STAT_CONN_TXN_PREPARE			1431
 /*! transaction: prepared transactions committed */
-#define	WT_STAT_CONN_TXN_PREPARE_COMMIT			1431
+#define	WT_STAT_CONN_TXN_PREPARE_COMMIT			1432
 /*! transaction: prepared transactions currently active */
-#define	WT_STAT_CONN_TXN_PREPARE_ACTIVE			1432
+#define	WT_STAT_CONN_TXN_PREPARE_ACTIVE			1433
 /*! transaction: prepared transactions rolled back */
-#define	WT_STAT_CONN_TXN_PREPARE_ROLLBACK		1433
+#define	WT_STAT_CONN_TXN_PREPARE_ROLLBACK		1434
 /*!
  * transaction: prepared transactions rolled back and do not remove the
  * history store entry
  */
-#define	WT_STAT_CONN_TXN_PREPARE_ROLLBACK_DO_NOT_REMOVE_HS_UPDATE	1434
+#define	WT_STAT_CONN_TXN_PREPARE_ROLLBACK_DO_NOT_REMOVE_HS_UPDATE	1435
 /*!
  * transaction: prepared transactions rolled back and fix the history
  * store entry with checkpoint reserved transaction id
  */
-#define	WT_STAT_CONN_TXN_PREPARE_ROLLBACK_FIX_HS_UPDATE_WITH_CKPT_RESERVED_TXNID	1435
+#define	WT_STAT_CONN_TXN_PREPARE_ROLLBACK_FIX_HS_UPDATE_WITH_CKPT_RESERVED_TXNID	1436
 /*! transaction: query timestamp calls */
-#define	WT_STAT_CONN_TXN_QUERY_TS			1436
+#define	WT_STAT_CONN_TXN_QUERY_TS			1437
 /*! transaction: race to read prepared update retry */
-#define	WT_STAT_CONN_TXN_READ_RACE_PREPARE_UPDATE	1437
+#define	WT_STAT_CONN_TXN_READ_RACE_PREPARE_UPDATE	1438
 /*! transaction: rollback to stable calls */
-#define	WT_STAT_CONN_TXN_RTS				1438
+#define	WT_STAT_CONN_TXN_RTS				1439
 /*!
  * transaction: rollback to stable history store records with stop
  * timestamps older than newer records
  */
-#define	WT_STAT_CONN_TXN_RTS_HS_STOP_OLDER_THAN_NEWER_START	1439
+#define	WT_STAT_CONN_TXN_RTS_HS_STOP_OLDER_THAN_NEWER_START	1440
 /*! transaction: rollback to stable inconsistent checkpoint */
-#define	WT_STAT_CONN_TXN_RTS_INCONSISTENT_CKPT		1440
+#define	WT_STAT_CONN_TXN_RTS_INCONSISTENT_CKPT		1441
 /*! transaction: rollback to stable keys removed */
-#define	WT_STAT_CONN_TXN_RTS_KEYS_REMOVED		1441
+#define	WT_STAT_CONN_TXN_RTS_KEYS_REMOVED		1442
 /*! transaction: rollback to stable keys restored */
-#define	WT_STAT_CONN_TXN_RTS_KEYS_RESTORED		1442
+#define	WT_STAT_CONN_TXN_RTS_KEYS_RESTORED		1443
 /*! transaction: rollback to stable pages visited */
-#define	WT_STAT_CONN_TXN_RTS_PAGES_VISITED		1443
+#define	WT_STAT_CONN_TXN_RTS_PAGES_VISITED		1444
 /*! transaction: rollback to stable restored tombstones from history store */
-#define	WT_STAT_CONN_TXN_RTS_HS_RESTORE_TOMBSTONES	1444
+#define	WT_STAT_CONN_TXN_RTS_HS_RESTORE_TOMBSTONES	1445
 /*! transaction: rollback to stable restored updates from history store */
-#define	WT_STAT_CONN_TXN_RTS_HS_RESTORE_UPDATES		1445
+#define	WT_STAT_CONN_TXN_RTS_HS_RESTORE_UPDATES		1446
 /*! transaction: rollback to stable skipping delete rle */
-#define	WT_STAT_CONN_TXN_RTS_DELETE_RLE_SKIPPED		1446
+#define	WT_STAT_CONN_TXN_RTS_DELETE_RLE_SKIPPED		1447
 /*! transaction: rollback to stable skipping stable rle */
-#define	WT_STAT_CONN_TXN_RTS_STABLE_RLE_SKIPPED		1447
+#define	WT_STAT_CONN_TXN_RTS_STABLE_RLE_SKIPPED		1448
 /*! transaction: rollback to stable sweeping history store keys */
-#define	WT_STAT_CONN_TXN_RTS_SWEEP_HS_KEYS		1448
+#define	WT_STAT_CONN_TXN_RTS_SWEEP_HS_KEYS		1449
 /*! transaction: rollback to stable tree walk skipping pages */
-#define	WT_STAT_CONN_TXN_RTS_TREE_WALK_SKIP_PAGES	1449
+#define	WT_STAT_CONN_TXN_RTS_TREE_WALK_SKIP_PAGES	1450
 /*! transaction: rollback to stable updates aborted */
-#define	WT_STAT_CONN_TXN_RTS_UPD_ABORTED		1450
+#define	WT_STAT_CONN_TXN_RTS_UPD_ABORTED		1451
 /*! transaction: rollback to stable updates removed from history store */
-#define	WT_STAT_CONN_TXN_RTS_HS_REMOVED			1451
+#define	WT_STAT_CONN_TXN_RTS_HS_REMOVED			1452
 /*! transaction: sessions scanned in each walk of concurrent sessions */
-#define	WT_STAT_CONN_TXN_SESSIONS_WALKED		1452
+#define	WT_STAT_CONN_TXN_SESSIONS_WALKED		1453
 /*! transaction: set timestamp calls */
-#define	WT_STAT_CONN_TXN_SET_TS				1453
+#define	WT_STAT_CONN_TXN_SET_TS				1454
 /*! transaction: set timestamp durable calls */
-#define	WT_STAT_CONN_TXN_SET_TS_DURABLE			1454
+#define	WT_STAT_CONN_TXN_SET_TS_DURABLE			1455
 /*! transaction: set timestamp durable updates */
-#define	WT_STAT_CONN_TXN_SET_TS_DURABLE_UPD		1455
+#define	WT_STAT_CONN_TXN_SET_TS_DURABLE_UPD		1456
 /*! transaction: set timestamp oldest calls */
-#define	WT_STAT_CONN_TXN_SET_TS_OLDEST			1456
+#define	WT_STAT_CONN_TXN_SET_TS_OLDEST			1457
 /*! transaction: set timestamp oldest updates */
-#define	WT_STAT_CONN_TXN_SET_TS_OLDEST_UPD		1457
+#define	WT_STAT_CONN_TXN_SET_TS_OLDEST_UPD		1458
 /*! transaction: set timestamp stable calls */
-#define	WT_STAT_CONN_TXN_SET_TS_STABLE			1458
+#define	WT_STAT_CONN_TXN_SET_TS_STABLE			1459
 /*! transaction: set timestamp stable updates */
-#define	WT_STAT_CONN_TXN_SET_TS_STABLE_UPD		1459
+#define	WT_STAT_CONN_TXN_SET_TS_STABLE_UPD		1460
 /*! transaction: transaction begins */
-#define	WT_STAT_CONN_TXN_BEGIN				1460
+#define	WT_STAT_CONN_TXN_BEGIN				1461
 /*! transaction: transaction checkpoint currently running */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_RUNNING		1461
+#define	WT_STAT_CONN_TXN_CHECKPOINT_RUNNING		1462
 /*!
  * transaction: transaction checkpoint currently running for history
  * store file
  */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_RUNNING_HS		1462
+#define	WT_STAT_CONN_TXN_CHECKPOINT_RUNNING_HS		1463
 /*! transaction: transaction checkpoint generation */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_GENERATION		1463
+#define	WT_STAT_CONN_TXN_CHECKPOINT_GENERATION		1464
 /*!
  * transaction: transaction checkpoint history store file duration
  * (usecs)
  */
-#define	WT_STAT_CONN_TXN_HS_CKPT_DURATION		1464
+#define	WT_STAT_CONN_TXN_HS_CKPT_DURATION		1465
 /*! transaction: transaction checkpoint max time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_MAX		1465
+#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_MAX		1466
 /*! transaction: transaction checkpoint min time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_MIN		1466
+#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_MIN		1467
 /*!
  * transaction: transaction checkpoint most recent duration for gathering
  * all handles (usecs)
  */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_DURATION	1467
+#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_DURATION	1468
 /*!
  * transaction: transaction checkpoint most recent duration for gathering
  * applied handles (usecs)
  */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_DURATION_APPLY	1468
+#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_DURATION_APPLY	1469
 /*!
  * transaction: transaction checkpoint most recent duration for gathering
  * skipped handles (usecs)
  */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_DURATION_SKIP	1469
+#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_DURATION_SKIP	1470
 /*! transaction: transaction checkpoint most recent handles applied */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_APPLIED	1470
+#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_APPLIED	1471
 /*! transaction: transaction checkpoint most recent handles skipped */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_SKIPPED	1471
+#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_SKIPPED	1472
 /*! transaction: transaction checkpoint most recent handles walked */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_WALKED	1472
+#define	WT_STAT_CONN_TXN_CHECKPOINT_HANDLE_WALKED	1473
 /*! transaction: transaction checkpoint most recent time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_RECENT		1473
+#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_RECENT		1474
 /*! transaction: transaction checkpoint prepare currently running */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_RUNNING	1474
+#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_RUNNING	1475
 /*! transaction: transaction checkpoint prepare max time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_MAX		1475
+#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_MAX		1476
 /*! transaction: transaction checkpoint prepare min time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_MIN		1476
+#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_MIN		1477
 /*! transaction: transaction checkpoint prepare most recent time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_RECENT		1477
+#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_RECENT		1478
 /*! transaction: transaction checkpoint prepare total time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_TOTAL		1478
+#define	WT_STAT_CONN_TXN_CHECKPOINT_PREP_TOTAL		1479
 /*! transaction: transaction checkpoint scrub dirty target */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_SCRUB_TARGET	1479
+#define	WT_STAT_CONN_TXN_CHECKPOINT_SCRUB_TARGET	1480
 /*! transaction: transaction checkpoint scrub time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_SCRUB_TIME		1480
+#define	WT_STAT_CONN_TXN_CHECKPOINT_SCRUB_TIME		1481
 /*! transaction: transaction checkpoint stop timing stress active */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_STOP_STRESS_ACTIVE	1481
+#define	WT_STAT_CONN_TXN_CHECKPOINT_STOP_STRESS_ACTIVE	1482
 /*! transaction: transaction checkpoint total time (msecs) */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_TOTAL		1482
+#define	WT_STAT_CONN_TXN_CHECKPOINT_TIME_TOTAL		1483
 /*! transaction: transaction checkpoints */
-#define	WT_STAT_CONN_TXN_CHECKPOINT			1483
+#define	WT_STAT_CONN_TXN_CHECKPOINT			1484
 /*! transaction: transaction checkpoints due to obsolete pages */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_OBSOLETE_APPLIED	1484
+#define	WT_STAT_CONN_TXN_CHECKPOINT_OBSOLETE_APPLIED	1485
 /*!
  * transaction: transaction checkpoints skipped because database was
  * clean
  */
-#define	WT_STAT_CONN_TXN_CHECKPOINT_SKIPPED		1485
-/*! transaction: transaction failures due to history store */
-#define	WT_STAT_CONN_TXN_FAIL_CACHE			1486
+#define	WT_STAT_CONN_TXN_CHECKPOINT_SKIPPED		1486
 /*!
  * transaction: transaction fsync calls for checkpoint after allocating
  * the transaction ID
diff --git a/src/third_party/wiredtiger/src/support/stat.c b/src/third_party/wiredtiger/src/support/stat.c
index 8c3ab3681e7..bd9efd34b9e 100644
--- a/src/third_party/wiredtiger/src/support/stat.c
+++ b/src/third_party/wiredtiger/src/support/stat.c
@@ -1472,6 +1472,7 @@ static const char *const __stats_connection_desc[] = {
   "transaction: Number of prepared updates committed",
   "transaction: Number of prepared updates repeated on the same key",
   "transaction: Number of prepared updates rolled back",
+  "transaction: oldest pinned transaction ID rolled back for eviction",
   "transaction: prepared transactions",
   "transaction: prepared transactions committed",
   "transaction: prepared transactions currently active",
@@ -1530,7 +1531,6 @@ static const char *const __stats_connection_desc[] = {
   "transaction: transaction checkpoints",
   "transaction: transaction checkpoints due to obsolete pages",
   "transaction: transaction checkpoints skipped because database was clean",
-  "transaction: transaction failures due to history store",
   "transaction: transaction fsync calls for checkpoint after allocating the transaction ID",
   "transaction: transaction fsync duration for checkpoint after allocating the transaction ID "
   "(usecs)",
@@ -2016,6 +2016,7 @@ __wt_stat_connection_clear_single(WT_CONNECTION_STATS *stats)
     stats->txn_prepared_updates_committed = 0;
     stats->txn_prepared_updates_key_repeated = 0;
     stats->txn_prepared_updates_rolledback = 0;
+    stats->txn_rollback_oldest_pinned = 0;
     stats->txn_prepare = 0;
     stats->txn_prepare_commit = 0;
     stats->txn_prepare_active = 0;
@@ -2072,7 +2073,6 @@ __wt_stat_connection_clear_single(WT_CONNECTION_STATS *stats)
     stats->txn_checkpoint = 0;
     stats->txn_checkpoint_obsolete_applied = 0;
     stats->txn_checkpoint_skipped = 0;
-    stats->txn_fail_cache = 0;
     stats->txn_checkpoint_fsync_post = 0;
     /* not clearing txn_checkpoint_fsync_post_duration */
     /* not clearing txn_pinned_range */
@@ -2578,6 +2578,7 @@ __wt_stat_connection_aggregate(WT_CONNECTION_STATS **from, WT_CONNECTION_STATS *
     to->txn_prepared_updates_committed += WT_STAT_READ(from, txn_prepared_updates_committed);
     to->txn_prepared_updates_key_repeated += WT_STAT_READ(from, txn_prepared_updates_key_repeated);
     to->txn_prepared_updates_rolledback += WT_STAT_READ(from, txn_prepared_updates_rolledback);
+    to->txn_rollback_oldest_pinned += WT_STAT_READ(from, txn_rollback_oldest_pinned);
     to->txn_prepare += WT_STAT_READ(from, txn_prepare);
     to->txn_prepare_commit += WT_STAT_READ(from, txn_prepare_commit);
     to->txn_prepare_active += WT_STAT_READ(from, txn_prepare_active);
@@ -2639,7 +2640,6 @@ __wt_stat_connection_aggregate(WT_CONNECTION_STATS **from, WT_CONNECTION_STATS *
     to->txn_checkpoint += WT_STAT_READ(from, txn_checkpoint);
     to->txn_checkpoint_obsolete_applied += WT_STAT_READ(from, txn_checkpoint_obsolete_applied);
     to->txn_checkpoint_skipped += WT_STAT_READ(from, txn_checkpoint_skipped);
-    to->txn_fail_cache += WT_STAT_READ(from, txn_fail_cache);
     to->txn_checkpoint_fsync_post += WT_STAT_READ(from, txn_checkpoint_fsync_post);
     to->txn_checkpoint_fsync_post_duration +=
       WT_STAT_READ(from, txn_checkpoint_fsync_post_duration);