Import wiredtiger: 8124d929c48ae8e4c0b1311374ea69b6ae4c48c5 from branch mongodb-4.4

ref: d44b1af8a8..8124d929c4
for: 4.3.2

WT-4995       Migrate Jenkins “wiredtiger-test-wtperf” job to Evergreen
WT-5048       wiredtiger_open with a corrupted meta file should always return WT_TRY_SALVAGE
WT-5169       WT_REF_LIMBO pages cannot support fast (leaf-page only) searches
WT-5211       Print mismatch information before dumping page and LAS
WT-5247       Ensure that only idempotent modify operations are logged
WT-5251       Increase frequency for Linux syscall test
WT-5252       Fix Ubuntu 18.04 PPC and zSeries unit-test failure in Evergreen

18 files changed, 202 insertions, 57 deletions

diff --git a/src/third_party/wiredtiger/.clang-format b/src/third_party/wiredtiger/.clang-format
index 5cd39db2e69..573572df901 100644
--- a/src/third_party/wiredtiger/.clang-format
+++ b/src/third_party/wiredtiger/.clang-format
@@ -49,14 +49,16 @@ ForEachMacros:
   - Q_FOREACH
   - BOOST_FOREACH
   - TAILQ_FOREACH
+  - WT_CELL_FOREACH_BEGIN
+  - WT_CELL_FOREACH_VRFY
   - WT_CKPT_FOREACH
+  - WT_COL_FOREACH
   - WT_EXT_FOREACH
   - WT_EXT_FOREACH_OFF
   - WT_FIX_FOREACH
-  - WT_CELL_FOREACH_BEGIN
-  - WT_CELL_FOREACH_VRFY
-  - WT_COL_FOREACH
   - WT_INTL_FOREACH_BEGIN
+  - WT_MODIFY_FOREACH_BEGIN
+  - WT_MODIFY_FOREACH_REVERSE
   - WT_ROW_FOREACH
   - WT_SKIP_FOREACH
 IncludeCategories:
diff --git a/src/third_party/wiredtiger/dist/s_funcs.list b/src/third_party/wiredtiger/dist/s_funcs.list
index bcedc19a459..0218937fffc 100644
--- a/src/third_party/wiredtiger/dist/s_funcs.list
+++ b/src/third_party/wiredtiger/dist/s_funcs.list
@@ -16,6 +16,7 @@ __wt_config_getone
 __wt_cursor_get_raw_value
 __wt_debug_addr
 __wt_debug_addr_print
+__wt_debug_cursor_las
 __wt_debug_cursor_page
 __wt_debug_offset
 __wt_debug_set_verbose
diff --git a/src/third_party/wiredtiger/dist/s_string.ok b/src/third_party/wiredtiger/dist/s_string.ok
index e770694e17c..66480a55eec 100644
--- a/src/third_party/wiredtiger/dist/s_string.ok
+++ b/src/third_party/wiredtiger/dist/s_string.ok
@@ -210,6 +210,7 @@ Kanowski's
 Kounavis
 LANGID
 LAS
+LASdump
 LF
 LLLLLL
 LLLLLLL
diff --git a/src/third_party/wiredtiger/import.data b/src/third_party/wiredtiger/import.data
index fb4ca494875..d88e2d1b501 100644
--- a/src/third_party/wiredtiger/import.data
+++ b/src/third_party/wiredtiger/import.data
@@ -1,5 +1,5 @@
 {
-    "commit": "d44b1af8a84ef93d9857432c9af5ef3b3adc8bdd", 
+    "commit": "8124d929c48ae8e4c0b1311374ea69b6ae4c48c5", 
     "github": "wiredtiger/wiredtiger.git", 
     "vendor": "wiredtiger", 
     "branch": "mongodb-4.4"
diff --git a/src/third_party/wiredtiger/src/block/block_open.c b/src/third_party/wiredtiger/src/block/block_open.c
index ba32bce74bc..868d7c5d149 100644
--- a/src/third_party/wiredtiger/src/block/block_open.c
+++ b/src/third_party/wiredtiger/src/block/block_open.c
@@ -345,8 +345,11 @@ __desc_read(WT_SESSION_IMPL *session, uint32_t allocsize, WT_BLOCK *block)
      * without some reason to believe they are WiredTiger files. The user may have entered the wrong
      * file name, and is now frantically pounding their interrupt key.
      */
-    if (desc->magic != WT_BLOCK_MAGIC || !checksum_matched)
+    if (desc->magic != WT_BLOCK_MAGIC || !checksum_matched) {
+        if (strcmp(block->name, WT_METAFILE) == 0)
+            WT_ERR_MSG(session, WT_TRY_SALVAGE, "%s is corrupted", block->name);
         WT_ERR_MSG(session, WT_ERROR, "%s does not appear to be a WiredTiger file", block->name);
+    }
 
     if (desc->majorv > WT_BLOCK_MAJOR_VERSION ||
       (desc->majorv == WT_BLOCK_MAJOR_VERSION && desc->minorv > WT_BLOCK_MINOR_VERSION))
diff --git a/src/third_party/wiredtiger/src/btree/bt_cursor.c b/src/third_party/wiredtiger/src/btree/bt_cursor.c
index 4e85f1528a8..11201846a38 100644
--- a/src/third_party/wiredtiger/src/btree/bt_cursor.c
+++ b/src/third_party/wiredtiger/src/btree/bt_cursor.c
@@ -101,17 +101,16 @@ __cursor_page_pinned(WT_CURSOR_BTREE *cbt, bool search_operation)
         return (false);
 
     /*
-     * If we are doing an update, we need a page with history, release the page so we get it again
-     * with history if required. Eviction may be locking the page, wait until we see a "normal"
-     * state and then test against that state (eviction may have already locked the page again).
+     * We need a page with history: updates need complete update lists and a read might be based on
+     * a different timestamp than the one that brought the page into memory. Release the page and
+     * read it again with history if required. Eviction may be locking the page, wait until we see a
+     * "normal" state and then test against that state (eviction may have already locked the page
+     * again).
      */
-    if (F_ISSET(&session->txn, WT_TXN_UPDATE)) {
-        while ((current_state = cbt->ref->state) == WT_REF_LOCKED)
-            __wt_yield();
-        return (current_state == WT_REF_MEM);
-    }
-
-    return (true);
+    while ((current_state = cbt->ref->state) == WT_REF_LOCKED)
+        __wt_yield();
+    WT_ASSERT(session, current_state == WT_REF_LIMBO || current_state == WT_REF_MEM);
+    return (current_state == WT_REF_MEM);
 }
 
 /*
diff --git a/src/third_party/wiredtiger/src/btree/bt_debug.c b/src/third_party/wiredtiger/src/btree/bt_debug.c
index f971de0e4f0..d4babb1df7c 100644
--- a/src/third_party/wiredtiger/src/btree/bt_debug.c
+++ b/src/third_party/wiredtiger/src/btree/bt_debug.c
@@ -698,6 +698,28 @@ __wt_debug_cursor_page(void *cursor_arg, const char *ofile)
 }
 
 /*
+ * __wt_debug_cursor_las --
+ *     Dump the LAS tree given a user cursor.
+ */
+int
+__wt_debug_cursor_las(void *cursor_arg, const char *ofile)
+  WT_GCC_FUNC_ATTRIBUTE((visibility("default")))
+{
+    WT_CONNECTION_IMPL *conn;
+    WT_CURSOR *cursor;
+    WT_CURSOR_BTREE *cbt;
+    WT_SESSION_IMPL *las_session;
+
+    cursor = cursor_arg;
+    conn = S2C((WT_SESSION_IMPL *)cursor->session);
+    las_session = conn->cache->las_session[0];
+    if (las_session == NULL)
+        return (0);
+    cbt = (WT_CURSOR_BTREE *)las_session->las_cursor;
+    return (__wt_debug_tree_all(las_session, cbt->btree, NULL, ofile));
+}
+
+/*
  * __debug_tree --
  *     Dump the in-memory information for a tree.
  */
diff --git a/src/third_party/wiredtiger/src/conn/conn_api.c b/src/third_party/wiredtiger/src/conn/conn_api.c
index 56b3febfeb1..462e096263e 100644
--- a/src/third_party/wiredtiger/src/conn/conn_api.c
+++ b/src/third_party/wiredtiger/src/conn/conn_api.c
@@ -1441,6 +1441,16 @@ __conn_config_file(
 
 err:
     WT_TRET(__wt_close(session, &fh));
+
+    /**
+     * Encountering an invalid configuration string from the base configuration file suggests
+     * that there is corruption present in the file.
+     */
+    if (!is_user && ret == EINVAL) {
+        F_SET(S2C(session), WT_CONN_DATA_CORRUPTION);
+        return (WT_ERROR);
+    }
+
     return (ret);
 }
 
@@ -1641,6 +1651,20 @@ __conn_single(WT_SESSION_IMPL *session, const char *cfg[])
         bytelock = false;
         ret = 0;
     }
+
+    /**
+     * The WiredTiger lock file will not be created if the WiredTiger file does not exist in the
+     * directory, suggesting possible corruption if the WiredTiger file was deleted. Suggest running
+     * salvage.
+     */
+    if (ret == ENOENT) {
+        WT_ERR(__wt_fs_exist(session, WT_WIREDTIGER, &exist));
+        if (!exist) {
+            F_SET(conn, WT_CONN_DATA_CORRUPTION);
+            WT_ERR(WT_ERROR);
+        }
+    }
+
     WT_ERR(ret);
     if (bytelock) {
         /*
@@ -1683,6 +1707,10 @@ __conn_single(WT_SESSION_IMPL *session, const char *cfg[])
             ret = 0;
         WT_ERR(ret);
     } else {
+        if (ret == ENOENT) {
+            F_SET(conn, WT_CONN_DATA_CORRUPTION);
+            WT_ERR(WT_ERROR);
+        }
         WT_ERR(ret);
         /*
          * Lock the WiredTiger file (for backward compatibility reasons as described above).
diff --git a/src/third_party/wiredtiger/src/conn/conn_dhandle.c b/src/third_party/wiredtiger/src/conn/conn_dhandle.c
index cc7f37bc7f0..c947954e75c 100644
--- a/src/third_party/wiredtiger/src/conn/conn_dhandle.c
+++ b/src/third_party/wiredtiger/src/conn/conn_dhandle.c
@@ -494,6 +494,11 @@ err:
     if (dhandle->type == WT_DHANDLE_TYPE_BTREE)
         __wt_evict_file_exclusive_off(session);
 
+    if (ret == ENOENT && F_ISSET(dhandle, WT_DHANDLE_IS_METADATA)) {
+        F_SET(S2C(session), WT_CONN_DATA_CORRUPTION);
+        return (WT_ERROR);
+    }
+
     return (ret);
 }
 
diff --git a/src/third_party/wiredtiger/src/include/extern.h b/src/third_party/wiredtiger/src/include/extern.h
index 7637f44ce3a..d42e0d43d9d 100644
--- a/src/third_party/wiredtiger/src/include/extern.h
+++ b/src/third_party/wiredtiger/src/include/extern.h
@@ -34,6 +34,8 @@ extern bool __wt_las_page_skip_locked(WT_SESSION_IMPL *session, WT_REF *ref)
   WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern bool __wt_lsm_chunk_visible_all(WT_SESSION_IMPL *session, WT_LSM_CHUNK *chunk)
   WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
+extern bool __wt_modify_idempotent(const void *modify)
+  WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern bool __wt_page_evict_urgent(WT_SESSION_IMPL *session, WT_REF *ref)
   WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern bool __wt_rwlock_islocked(WT_SESSION_IMPL *session, WT_RWLOCK *l)
@@ -572,6 +574,8 @@ extern int __wt_debug_addr(WT_SESSION_IMPL *session, const uint8_t *addr, size_t
   const char *ofile) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern int __wt_debug_addr_print(WT_SESSION_IMPL *session, const uint8_t *addr, size_t addr_size)
   WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
+extern int __wt_debug_cursor_las(void *cursor_arg, const char *ofile) WT_GCC_FUNC_DECL_ATTRIBUTE(
+  (visibility("default"))) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern int __wt_debug_cursor_page(void *cursor_arg, const char *ofile) WT_GCC_FUNC_DECL_ATTRIBUTE(
   (visibility("default"))) WT_GCC_FUNC_DECL_ATTRIBUTE((warn_unused_result));
 extern int __wt_debug_disk(WT_SESSION_IMPL *session, const WT_PAGE_HEADER *dsk, const char *ofile)
diff --git a/src/third_party/wiredtiger/src/meta/meta_turtle.c b/src/third_party/wiredtiger/src/meta/meta_turtle.c
index 80e409f380f..db790537c79 100644
--- a/src/third_party/wiredtiger/src/meta/meta_turtle.c
+++ b/src/third_party/wiredtiger/src/meta/meta_turtle.c
@@ -335,7 +335,7 @@ err:
      */
     if (ret == 0 || strcmp(key, WT_METADATA_COMPAT) == 0 || F_ISSET(S2C(session), WT_CONN_SALVAGE))
         return (ret);
-    WT_PANIC_RET(session, ret, "%s: fatal turtle file read error", WT_METADATA_TURTLE);
+    WT_PANIC_RET(session, WT_TRY_SALVAGE, "%s: fatal turtle file read error", WT_METADATA_TURTLE);
 }
 
 /*
diff --git a/src/third_party/wiredtiger/src/support/modify.c b/src/third_party/wiredtiger/src/support/modify.c
index 086fb4b3920..56d44af77ef 100644
--- a/src/third_party/wiredtiger/src/support/modify.c
+++ b/src/third_party/wiredtiger/src/support/modify.c
@@ -39,6 +39,36 @@
     while (0)
 
 /*
+ * __wt_modify_idempotent --
+ *     Check if a modify operation is idempotent.
+ */
+bool
+__wt_modify_idempotent(const void *modify)
+{
+    WT_MODIFY mod;
+    size_t tmp;
+    const size_t *p;
+    int nentries;
+
+    /* Get the number of modify entries. */
+    p = modify;
+    memcpy(&tmp, p++, sizeof(size_t));
+    nentries = (int)tmp;
+
+    WT_MODIFY_FOREACH_BEGIN (mod, p, nentries, 0) {
+        /*
+         * If the number of bytes being replaced doesn't match the number of bytes being written,
+         * we're resizing and the operation isn't idempotent.
+         */
+        if (mod.size != mod.data.size)
+            return (false);
+    }
+    WT_MODIFY_FOREACH_END;
+
+    return (true);
+}
+
+/*
  * __wt_modify_pack --
  *     Pack a modify structure into a buffer.
  */
@@ -224,8 +254,7 @@ __modify_fast_path(WT_ITEM *value, const size_t *p, int nentries, int *nappliedp
      */
     fastpath = first = true;
     *nappliedp = 0;
-    WT_MODIFY_FOREACH_BEGIN(current, p, nentries, 0)
-    {
+    WT_MODIFY_FOREACH_BEGIN (current, p, nentries, 0) {
         datasz += current.data.size;
 
         if (fastpath && current.data.size == current.size &&
@@ -295,8 +324,7 @@ __modify_apply_no_overlap(WT_SESSION_IMPL *session, WT_ITEM *value, const size_t
 
     from = (const uint8_t *)value->data + value->size;
     to = (uint8_t *)value->data + destsz;
-    WT_MODIFY_FOREACH_REVERSE(current, p, nentries, napplied, datasz)
-    {
+    WT_MODIFY_FOREACH_REVERSE (current, p, nentries, napplied, datasz) {
         /* Move the current unmodified block into place if necessary. */
         sz = WT_PTRDIFF(to, value->data) - (current.offset + current.data.size);
         from -= sz;
@@ -374,8 +402,7 @@ __wt_modify_apply(WT_CURSOR *cursor, const void *modify)
         goto done;
     }
 
-    WT_MODIFY_FOREACH_BEGIN(mod, p, nentries, napplied)
-    {
+    WT_MODIFY_FOREACH_BEGIN (mod, p, nentries, napplied) {
         WT_RET(__modify_apply_one(session, value, &mod, sformat));
     }
     WT_MODIFY_FOREACH_END;
diff --git a/src/third_party/wiredtiger/src/txn/txn_log.c b/src/third_party/wiredtiger/src/txn/txn_log.c
index 124465cc529..9dfb65306ca 100644
--- a/src/third_party/wiredtiger/src/txn/txn_log.c
+++ b/src/third_party/wiredtiger/src/txn/txn_log.c
@@ -80,7 +80,16 @@ __txn_op_log(
 #endif
         switch (upd->type) {
         case WT_UPDATE_MODIFY:
-            WT_RET(__wt_logop_row_modify_pack(session, logrec, fileid, &cursor->key, &value));
+            /*
+             * Write full updates to the log for size-changing modify operations: they aren't
+             * idempotent and recovery cannot guarantee that they will be applied exactly once. We
+             * rely on the cursor value already having the modify applied.
+             */
+            if (__wt_modify_idempotent(upd->data))
+                WT_RET(__wt_logop_row_modify_pack(session, logrec, fileid, &cursor->key, &value));
+            else
+                WT_RET(
+                  __wt_logop_row_put_pack(session, logrec, fileid, &cursor->key, &cursor->value));
             break;
         case WT_UPDATE_STANDARD:
             WT_RET(__wt_logop_row_put_pack(session, logrec, fileid, &cursor->key, &value));
@@ -97,7 +106,10 @@ __txn_op_log(
 
         switch (upd->type) {
         case WT_UPDATE_MODIFY:
-            WT_RET(__wt_logop_col_modify_pack(session, logrec, fileid, recno, &value));
+            if (__wt_modify_idempotent(upd->data))
+                WT_RET(__wt_logop_col_modify_pack(session, logrec, fileid, recno, &value));
+            else
+                WT_RET(__wt_logop_col_put_pack(session, logrec, fileid, recno, &cursor->value));
             break;
         case WT_UPDATE_STANDARD:
             WT_RET(__wt_logop_col_put_pack(session, logrec, fileid, recno, &value));
diff --git a/src/third_party/wiredtiger/test/evergreen.yml b/src/third_party/wiredtiger/test/evergreen.yml
index 97d69537a9d..76cdee3ebcb 100755
--- a/src/third_party/wiredtiger/test/evergreen.yml
+++ b/src/third_party/wiredtiger/test/evergreen.yml
@@ -231,6 +231,13 @@ tasks:
         vars:
           posix_configure_flags: --enable-silent-rules --enable-diagnostic --enable-strict --enable-python
 
+  - name: compile-wtperf
+    commands:
+      - func: "get project"
+      - func: "compile wiredtiger"
+        vars:
+          posix_configure_flags: --enable-strict --enable-diagnostic
+
   - name: make-check-test
     depends_on:
       - name: compile
@@ -1586,6 +1593,27 @@ tasks:
           display_name: Coverage report
           remote_file: wiredtiger/${build_variant}/${revision}/coverage_report/coverage_report_${build_id}.html
 
+  - name: wtperf-test
+    depends_on:
+      - name: compile-wtperf
+    commands:
+      - func: "fetch artifacts"
+        vars:
+          dependent_task: compile-wtperf
+      - command: shell.exec
+        params:
+          working_dir: "wiredtiger/build_posix"
+          script: |
+            set -o errexit
+            set -o verbose
+            # The test will generate WT_TEST directory automatically
+            dir=../bench/wtperf/stress
+            for file in `ls $dir`
+            do
+              ./bench/wtperf/wtperf -O $dir/$file -o verbose=2
+              cp -rf WT_TEST WT_TEST_$file
+            done
+
 buildvariants:
 - name: ubuntu1804
   display_name: Ubuntu 18.04
@@ -1603,11 +1631,14 @@ buildvariants:
     - name: compile-ubsan
     - name: ubsan-test
     - name: linux-directio
+    - name: syscall-linux
     - name: make-check-asan-test
     - name: configure-combinations
     - name: checkpoint-filetypes-test
     - name: coverage-report
     - name: unit-test-long
+    - name: compile-wtperf
+    - name: wtperf-test
 
 - name: ubuntu1804-python3
   display_name: Ubuntu 18.04 (Python3)
@@ -1633,19 +1664,6 @@ buildvariants:
   tasks:
     - name: package
 
-- name: syscall-linux
-  display_name: Syscall Linux
-  batchtime: 10080 # a week
-  run_on:
-  - ubuntu1804-test
-  expansions:
-    test_env_vars: PATH=/opt/mongodbtoolchain/v3/bin:$PATH LD_LIBRARY_PATH=$(pwd)/.libs top_srcdir=$(pwd)/.. top_builddir=$(pwd)
-    smp_command: -j $(grep -c ^processor /proc/cpuinfo)
-    make_command: PATH=/opt/mongodbtoolchain/v3/bin:$PATH make
-  tasks:
-    - name: compile
-    - name: syscall-linux
-
 - name: linux-no-ftruncate
   display_name: Linux no ftruncate
   batchtime: 10080 # 1 day
@@ -1755,6 +1773,7 @@ buildvariants:
     smp_command: -j $(grep -c ^processor /proc/cpuinfo)
     posix_configure_flags: --enable-silent-rules --enable-diagnostic --enable-python --enable-zlib --enable-snappy --enable-strict --enable-static --prefix=$(pwd)/LOCAL_INSTALL
     make_command: PATH=/opt/mongodbtoolchain/v3/bin:$PATH make
+    test_env_vars: PATH=/opt/mongodbtoolchain/v3/bin:$PATH LD_LIBRARY_PATH=$(pwd)/.libs top_srcdir=$(pwd)/.. top_builddir=$(pwd)
   tasks:
   - name: compile
   - name: unit-test
@@ -1767,6 +1786,7 @@ buildvariants:
     smp_command: -j $(grep -c ^processor /proc/cpuinfo)
     posix_configure_flags: --enable-silent-rules --enable-diagnostic --enable-python --enable-zlib --enable-snappy --enable-strict --enable-static --prefix=$(pwd)/LOCAL_INSTALL
     make_command: PATH=/opt/mongodbtoolchain/v3/bin:$PATH make
+    test_env_vars: PATH=/opt/mongodbtoolchain/v3/bin:$PATH LD_LIBRARY_PATH=$(pwd)/.libs:$(pwd)/lang/python top_srcdir=$(pwd)/.. top_builddir=$(pwd)
   tasks:
   - name: compile
   - name: unit-test
diff --git a/src/third_party/wiredtiger/test/format/format.h b/src/third_party/wiredtiger/test/format/format.h
index d8cfea5730a..bae89f7e2f6 100644
--- a/src/third_party/wiredtiger/test/format/format.h
+++ b/src/third_party/wiredtiger/test/format/format.h
@@ -63,6 +63,7 @@ typedef struct {
     char *home_backup_init;  /* Initialize backup command */
     char *home_config;       /* Run CONFIG file path */
     char *home_init;         /* Initialize home command */
+    char *home_lasdump;      /* LAS dump filename */
     char *home_log;          /* Operation log file path */
     char *home_pagedump;     /* Page dump filename */
     char *home_rand;         /* RNG log file path */
diff --git a/src/third_party/wiredtiger/test/format/snap.c b/src/third_party/wiredtiger/test/format/snap.c
index e68309c0149..eed296e212f 100644
--- a/src/third_party/wiredtiger/test/format/snap.c
+++ b/src/third_party/wiredtiger/test/format/snap.c
@@ -191,19 +191,14 @@ snap_verify(WT_CURSOR *cursor, TINFO *tinfo, SNAP_OPS *snap)
             return (0);
     }
 
-/* Things went pear-shaped. */
-#ifdef HAVE_DIAGNOSTIC
-    fprintf(stderr, "snapshot-isolation error: Dumping page to %s\n", g.home_pagedump);
-    testutil_check(__wt_debug_cursor_page(cursor, g.home_pagedump));
-#endif
+    /* Things went pear-shaped. */
     switch (g.type) {
     case FIX:
-        testutil_die(ret, "snapshot-isolation: %" PRIu64
-                          " search: "
-                          "expected {0x%02x}, found {0x%02x}",
-          keyno, snap->op == REMOVE ? 0 : *(uint8_t *)snap->vdata,
-          ret == WT_NOTFOUND ? 0 : *(uint8_t *)value->data);
-    /* NOTREACHED */
+        fprintf(stderr,
+          "snapshot-isolation: %" PRIu64 " search: expected {0x%02x}, found {0x%02x}\n", keyno,
+          snap->op == REMOVE ? 0U : *(uint8_t *)snap->vdata,
+          ret == WT_NOTFOUND ? 0U : *(uint8_t *)value->data);
+        break;
     case ROW:
         fprintf(
           stderr, "snapshot-isolation %.*s search mismatch\n", (int)key->size, (char *)key->data);
@@ -216,10 +211,7 @@ snap_verify(WT_CURSOR *cursor, TINFO *tinfo, SNAP_OPS *snap)
             fprintf(stderr, "   found {deleted}\n");
         else
             print_item_data("   found", value->data, value->size);
-
-        testutil_die(
-          ret, "snapshot-isolation: %.*s search mismatch", (int)key->size, (char *)key->data);
-    /* NOTREACHED */
+        break;
     case VAR:
         fprintf(stderr, "snapshot-isolation %" PRIu64 " search mismatch\n", keyno);
 
@@ -231,8 +223,35 @@ snap_verify(WT_CURSOR *cursor, TINFO *tinfo, SNAP_OPS *snap)
             fprintf(stderr, "   found {deleted}\n");
         else
             print_item_data("   found", value->data, value->size);
+        break;
+    }
 
+#ifdef HAVE_DIAGNOSTIC
+    /*
+     * We have a mismatch. Try to print out as much information as we can. In doing so, we are
+     * calling into the debug code directly and that does not take locks. So it is possible that the
+     * calls may crash in some way.
+     *
+     * The most important information is the key/value mismatch information. Then try to dump out
+     * the other information. Right now we dump the entire lookaside table including what is on
+     * disk. That can potentially be very large. If it becomes a problem, this can be modified to
+     * just dump out the page this key is on.
+     */
+    fprintf(stderr, "snapshot-isolation error: Dumping page to %s\n", g.home_pagedump);
+    testutil_check(__wt_debug_cursor_page(cursor, g.home_pagedump));
+    fprintf(stderr, "snapshot-isolation error: Dumping LAS to %s\n", g.home_lasdump);
+    testutil_check(__wt_debug_cursor_las(cursor, g.home_lasdump));
+    if (g.logging)
+        testutil_check(cursor->session->log_flush(cursor->session, "sync=off"));
+#endif
+    switch (g.type) {
+    case FIX:
+    case VAR:
         testutil_die(ret, "snapshot-isolation: %" PRIu64 " search mismatch", keyno);
+    /* NOTREACHED */
+    case ROW:
+        testutil_die(
+          ret, "snapshot-isolation: %.*s search mismatch", (int)key->size, (char *)key->data);
         /* NOTREACHED */
     }
 
diff --git a/src/third_party/wiredtiger/test/format/util.c b/src/third_party/wiredtiger/test/format/util.c
index bdc98d25b46..95ded261097 100644
--- a/src/third_party/wiredtiger/test/format/util.c
+++ b/src/third_party/wiredtiger/test/format/util.c
@@ -329,6 +329,11 @@ path_setup(const char *home)
     g.home_log = dmalloc(len);
     testutil_check(__wt_snprintf(g.home_log, len, "%s/%s", g.home, "log"));
 
+    /* LAS dump file. */
+    len = strlen(g.home) + strlen("LASdump") + 2;
+    g.home_lasdump = dmalloc(len);
+    testutil_check(__wt_snprintf(g.home_lasdump, len, "%s/%s", g.home, "LASdump"));
+
     /* Page dump file. */
     len = strlen(g.home) + strlen("pagedump") + 2;
     g.home_pagedump = dmalloc(len);
diff --git a/src/third_party/wiredtiger/test/suite/test_txn19.py b/src/third_party/wiredtiger/test/suite/test_txn19.py
index c63e9f9c6e9..87cbf608a7c 100755
--- a/src/third_party/wiredtiger/test/suite/test_txn19.py
+++ b/src/third_party/wiredtiger/test/suite/test_txn19.py
@@ -520,11 +520,7 @@ class test_txn19_meta(wttest.WiredTigerTestCase, suite_subprocess):
 
         if expect_fail:
             self.check_file_contains_one_of(errfile,
-                ['/unknown configuration key/',
-                '/handle-open:/',
-                '/turtle file read error: WT_NOTFOUND: item not found/',
-                'WT_ERROR: non-specific WiredTiger error',
-                'WT_TRY_SALVAGE: database corruption detected'])
+                ['WT_TRY_SALVAGE: database corruption detected'])
 
         for salvagedir in [ newdir, newdir2 ]:
             # Removing the 'WiredTiger.turtle' file has weird behavior: