diff --git a/manifest b/manifest
index a0a0be1778..8db75f34fa 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Merge\sversion\s3.37.0\sinto\sthe\sbegin-concurrent-pnu-wal2\sbranch.
-D 2021-11-27T15:11:55.095
+C Merge\scheckpoint-on-close\sfix\sfrom\swal2\sbranch.
+D 2021-12-15T13:42:40.710
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -641,7 +641,7 @@ F src/vdbetrace.c fe0bc29ebd4e02c8bc5c1945f1d2e6be5927ec12c06d89b03ef2a4def34bf8
 F src/vdbevtab.c f99b275366c5fc5e2d99f734729880994ab9500bdafde7fae3b02d562b9d323c
 F src/vtab.c 9d5c3f49d3a6959b6eef287bb8fa773563102a80a835c3314c57144412709e78
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
-F src/wal.c 8a81802f21762b63d0100ff240f983adcd1cb3807fc8cf73deafcd8268483e6b
+F src/wal.c 5b92441319c3c7cf2833e64d7d1f38efa59a9458240c991b67a105541432c3d1
 F src/wal.h 7a733af13b966ecb81872ce397e862116b3575ea53245b90b139a2873ee87825
 F src/walker.c f890a3298418d7cba3b69b8803594fdc484ea241206a8dfa99db6dd36f8cbb3b
 F src/where.c de0d4ff409c7b62a8803f9f267cc2c7fedddbc00de9ab7b5382c507383c18665
@@ -1743,12 +1743,13 @@ F test/wal2big.test 0b4ec526f9ca4bbabc355042c38045ae2e253fb46eb327bb7693d0122bc6
 F test/wal2concurrent.test 7fc3e570073683a2a28f42bda46ecf516f5bc82afd703c1fbf4aa38e18fb3361
 F test/wal2fault.test 2e8e60cacd5bcd451618aeffd05f676894d17202d3e2986e288d36e2c5993249
 F test/wal2lock.test 0ef98d72dc6bcf7711dedd684760488400d9a9a6eec0dc5d3822060437793552
+F test/wal2openclose.test 2b26be723ea7f4263c8d5d70b37efd1c359561a0526e39466c45fe8e6478daee
 F test/wal2recover.test ba8f4bc9397c838734619f9e759bd98b00e355347b3cf80a2e677610d231d5d8
 F test/wal2recover2.test 698bd0da28b84f470dc5dd50340401fdb50cf8d7894de27d55b61d22130bb1e1
 F test/wal2rewrite.test 6ca6f631ffcf871240beab5f02608913fd075c6d0d31310b026c8383c65c9f9c
 F test/wal2rollback.test 23adc4a099b23f6aaea8b04fdca1c35861d887dd80f8be7da2d5273eb777e428
 F test/wal2savepoint.test 3793a0ae97011fca358f79775f5d7d9f85da75c8e67686e2e19713da0cb0d99c
-F test/wal2simple.test 4a9bfc34dc888e75acb4e7bdce0bf15e960cbee02f185c07a396b35c49d4431d
+F test/wal2simple.test 320a08927f307d0ead26fa3fcef4e3f64279f49be9504f918cb33294f75aeec8
 F test/wal2snapshot.test f6c3945bea572fd8745774e95b8dca1e5832c696e2251bb0db33391ee567fe60
 F test/wal3.test 2a93004bc0fb2b5c29888964024695bade278ab2
 F test/wal4.test 4744e155cd6299c6bd99d3eab1c82f77db9cdb3c
@@ -1964,7 +1965,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8a9fad0f71135b0218ccddeabb7db0c41cfac08ec772f8b3b1df7751485bc30a 3425af625bac6c89950a50c2a22c4b7f66b0080811fe16ec8879158420641d5c
-R 0a90a070d8addea4d9c4ecfd9760de90
-U drh
-Z 64736bb5cbda5070d127800560ceb017
+P 2171996a02ad2ec571570749ccee421bc0859a690c8393c5edda6cf164d2c8db b0a70a2356c44d65c54c6d9bdf05972071462e72c28d6c6e593147ffa3d27ef2
+R a8bdc946bdcbc515532b753a755a4462
+U dan
+Z 007a67a7baf46f1b69e8ed1cd0cfdb34
diff --git a/manifest.uuid b/manifest.uuid
index 61faa6e268..f5b5a8fdd1 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-2171996a02ad2ec571570749ccee421bc0859a690c8393c5edda6cf164d2c8db
\ No newline at end of file
+a92eca6c9ca45208df5764e50dec2b257244176f5893b4bee7f9475c4e8d8c8b
\ No newline at end of file
diff --git a/src/wal.c b/src/wal.c
index c36f0f9c92..e8016d8df9 100644
--- a/src/wal.c
+++ b/src/wal.c
@@ -797,6 +797,7 @@ struct Wal {
 #ifdef SQLITE_ENABLE_SNAPSHOT
   WalIndexHdr *pSnapshot;    /* Start transaction here if not NULL */
 #endif
+  int bClosing;              /* Set to true at start of sqlite3WalClose() */
   int bWal2;                 /* bWal2 flag passed to WalOpen() */
 #ifdef SQLITE_ENABLE_SETLK_TIMEOUT
   sqlite3 *db;
@@ -2854,6 +2855,7 @@ int sqlite3WalClose(
   int rc = SQLITE_OK;
   if( pWal ){
     int isDelete = 0;             /* True to unlink wal and wal-index files */
+    pWal->bClosing = 1;
 
     /* If an EXCLUSIVE lock can be obtained on the database file (using the
     ** ordinary, rollback-mode locking methods, this guarantees that the
@@ -5068,13 +5070,17 @@ int sqlite3WalCheckpoint(
     }
   }
 
-  if( isChanged ){
+  if( isChanged && pWal->bClosing==0 ){
     /* If a new wal-index header was loaded before the checkpoint was 
     ** performed, then the pager-cache associated with pWal is now
     ** out of date. So zero the cached wal-index header to ensure that
     ** next time the pager opens a snapshot on this database it knows that
     ** the cache needs to be reset.
-    */
+    **
+    ** Except, do not do this if the wal is being closed. In this case
+    ** the caller needs the wal-index header to check if the database is
+    ** in wal2 mode and the "other" wal file also needs to be checkpointed.
+    ** Besides, the pager cache will not be used again in this case. */
     memset(&pWal->hdr, 0, sizeof(WalIndexHdr));
   }
 
diff --git a/test/wal2openclose.test b/test/wal2openclose.test
new file mode 100644
index 0000000000..66e5875813
--- /dev/null
+++ b/test/wal2openclose.test
@@ -0,0 +1,81 @@
+# 2017 September 19
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this file is testing the operation of the library in
+# "PRAGMA journal_mode=WAL2" mode.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+source $testdir/malloc_common.tcl
+source $testdir/wal_common.tcl
+
+set testprefix wal2openclose
+ifcapable !wal {finish_test ; return }
+
+do_execsql_test 1.0 {
+  CREATE TABLE t1(a, b, c);
+  PRAGMA journal_mode = wal2;
+  PRAGMA wal_autocheckpoint = 0;
+  PRAGMA journal_size_limit = 75000;
+} {wal2 0 75000}
+
+do_test 1.1 {
+  for {set ii 1} {$ii <= 200} {incr ii} {
+    execsql {
+      INSERT INTO t1 VALUES($ii, $ii, $ii);
+    }
+  }
+  expr ([file size test.db-wal2] - 75000) > 30000
+} {1}
+
+do_test 1.2 {
+  db close
+  list [file exists test.db-wal] [file exists test.db-wal2]
+} {0 0}
+
+sqlite3 db test.db
+do_execsql_test 1.3 {
+  SELECT sum(c) FROM t1
+} {20100}
+db close
+
+#-------------------------------------------------------------------------
+reset_db
+do_execsql_test 2.0 {
+  CREATE TABLE t1(a, b, c);
+  PRAGMA journal_mode = wal2;
+  INSERT INTO t1 VALUES(1, 2, 3);
+} {wal2}
+db_save_and_close
+
+db_restore_and_reopen
+do_execsql_test 2.1 {
+  SELECT * FROM t1;
+} {1 2 3}
+
+do_test 2.2 {
+  sqlite3 db2 test.db
+  db2 eval {INSERT INTO t1 VALUES(4, 5, 6)}
+  db2 close
+} {}
+
+breakpoint
+db close
+sqlite3 db test.db
+do_execsql_test 2.2 {
+  SELECT * FROM t1;
+} {1 2 3 4 5 6}
+
+
+
+finish_test
diff --git a/test/wal2simple.test b/test/wal2simple.test
index e17fb66ec9..e63f4e1759 100644
--- a/test/wal2simple.test
+++ b/test/wal2simple.test
@@ -361,23 +361,23 @@ do_test 7.3.1 {
       SELECT count(*) FROM t1;
   } db2
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 3176 11264}
+} {12608 3176 12288}
 do_test 7.3.2 {
   execsql { PRAGMA wal_checkpoint }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 3176 21504}
+} {12608 3176 22528}
 do_test 7.3.3 {
   execsql { 
     INSERT INTO t1 VALUES(randomblob(10000));
     INSERT INTO t1 VALUES(randomblob(500));
   }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 18896 21504}
+} {12608 18896 22528}
 do_test 7.3.4 {
   execsql END db2
   execsql { INSERT INTO t1 VALUES(randomblob(5000)); }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 18896 21504}
+} {12608 18896 22528}
 
 # Connection db2 is holding a PART2 lock. 
 #
@@ -406,22 +406,22 @@ do_test 7.4.1 {
       SELECT count(*) FROM t1;
   } db2
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 12608 44032}
+} {12608 12608 50176}
 do_test 7.4.2 {
   execsql { 
     INSERT INTO t1 VALUES(randomblob(5000));
   }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 12608 44032}
+} {12608 12608 50176}
 do_test 7.4.3 {
   execsql { PRAGMA wal_checkpoint }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 12608 44032}
+} {12608 12608 50176}
 do_test 7.4.4 {
   execsql END db2
   execsql { PRAGMA wal_checkpoint }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 12608 54272}
+} {12608 12608 60416}
 
 # Connection db2 is holding a PART1_FULL2 lock. 
 #
@@ -451,24 +451,24 @@ do_test 7.5.1 {
       SELECT count(*) FROM t1;
   } db2
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 12608 64512}
+} {12608 12608 76800}
 do_test 7.5.2 {
   execsql { PRAGMA wal_checkpoint }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {12608 12608 75776}
+} {12608 12608 87040}
 do_test 7.5.3.1 {
   execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {14704 12608 75776}
+} {14704 12608 87040}
 do_test 7.5.3.2 {
   execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {22040 12608 75776}
+} {22040 12608 87040}
 do_test 7.5.4 {
   execsql END db2
   execsql { INSERT INTO t1 VALUES(randomblob(5000)) }
   list [file size test.db-wal] [file size test.db-wal2] [file size test.db]
-} {22040 12608 75776}
+} {22040 12608 87040}
 
 
 finish_test