diff --git a/src/viztracer/web_dist/trace_processor b/src/viztracer/web_dist/trace_processor
index 50e7fe0f..0ee1e788 100755
--- a/src/viztracer/web_dist/trace_processor
+++ b/src/viztracer/web_dist/trace_processor
@@ -30,18 +30,18 @@ exec python3 - "$@" <<'#'EOF
 
 
 # ----- Amalgamator: begin of python/perfetto/prebuilts/manifests/trace_processor_shell.py
-# This file has been generated by: tools/roll-prebuilts v37.0
+# This file has been generated by: tools/roll-prebuilts v46.0
 TRACE_PROCESSOR_SHELL_MANIFEST = [{
     'arch':
         'mac-amd64',
     'file_name':
         'trace_processor_shell',
     'file_size':
-        9551608,
+        9503800,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/mac-amd64/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/mac-amd64/trace_processor_shell',
     'sha256':
-        'f3def324604f551fdf7df088363aebf74de573fdaa02796fd994f1863ad58463',
+        'c979a616c2aeada9ff5e0807f15089c7415de7e1f19670945792be5953c05f87',
     'platform':
         'darwin',
     'machine': ['x86_64']
@@ -51,11 +51,11 @@ TRACE_PROCESSOR_SHELL_MANIFEST = [{
     'file_name':
         'trace_processor_shell',
     'file_size':
-        8064168,
+        8873912,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/mac-arm64/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/mac-arm64/trace_processor_shell',
     'sha256':
-        'f34a2cfb4f93579452bbaf4f47c9b0fe475394d55316c9626949760c206ec801',
+        '8f88e9ec002fb0e95bcfdd655e1a9632487010876a234bc545c85c44d0019294',
     'platform':
         'darwin',
     'machine': ['arm64']
@@ -65,11 +65,11 @@ TRACE_PROCESSOR_SHELL_MANIFEST = [{
     'file_name':
         'trace_processor_shell',
     'file_size':
-        9415488,
+        9675688,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/linux-amd64/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/linux-amd64/trace_processor_shell',
     'sha256':
-        '86d133fc2fe0204693d2b22e9287363cb44bf76794b0091d4d0bb3388b7cd8d5',
+        '70adf26bc45d6de8327b1e46e98f64d4fe8ccf9fd31a1391bb0916c31aaa9df8',
     'platform':
         'linux',
     'machine': ['x86_64']
@@ -79,11 +79,11 @@ TRACE_PROCESSOR_SHELL_MANIFEST = [{
     'file_name':
         'trace_processor_shell',
     'file_size':
-        6880412,
+        7098492,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/linux-arm/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/linux-arm/trace_processor_shell',
     'sha256':
-        '21fd4b2ad68b1f9829cee72d3905b1712cbfa5e169e89b89cdd0a3a4b1682e7d',
+        'b9d5abb196a99d1ade08db3d97bff3c71e8ee4ccd6fedb6332effa4d5d50c21d',
     'platform':
         'linux',
     'machine': ['armv6l', 'armv7l', 'armv8l']
@@ -93,11 +93,11 @@ TRACE_PROCESSOR_SHELL_MANIFEST = [{
     'file_name':
         'trace_processor_shell',
     'file_size':
-        8843272,
+        9297416,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/linux-arm64/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/linux-arm64/trace_processor_shell',
     'sha256':
-        '97a6fb150fd6655f03394d8ad166fd2041a1b4ca56a9e7ce5b35902ff64e1a35',
+        'b0495e1ba864f3a315a31353e02f25fe8bcfc993ec6cdae1545f12f33f008c8c',
     'platform':
         'linux',
     'machine': ['aarch64']
@@ -107,55 +107,55 @@ TRACE_PROCESSOR_SHELL_MANIFEST = [{
     'file_name':
         'trace_processor_shell',
     'file_size':
-        6497440,
+        7111084,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/android-arm/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/android-arm/trace_processor_shell',
     'sha256':
-        '6018ce36314a75693c5e5c2a69a3aacc9848385bd3ab9121e23de70df5188e1e'
+        'd8aa4b6460aca2e166755952fa14010d1f80ddb6b6dc406ca2b5246f9885b153'
 }, {
     'arch':
         'android-arm64',
     'file_name':
         'trace_processor_shell',
     'file_size':
-        8019768,
+        9200536,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/android-arm64/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/android-arm64/trace_processor_shell',
     'sha256':
-        '4e36255ebcd5e19fe26def6578cc604d636df9c4fa335ec5901e6cd9aba92ac3'
+        '1c1843ec2e127b5f7aa8eb9e8d2c216e4cc99f681ecf437ff09f7abc56191cef'
 }, {
     'arch':
         'android-x86',
     'file_name':
         'trace_processor_shell',
     'file_size':
-        8897636,
+        10094664,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/android-x86/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/android-x86/trace_processor_shell',
     'sha256':
-        'f21573cc77603150e461402c6f032b7ff8f103debcd9d9b2093f521a69f581f7'
+        '4501c9aa2eaaec62155aac914a35b3c61e9d434e765b20fcefa49b7d01f978f0'
 }, {
     'arch':
         'android-x64',
     'file_name':
         'trace_processor_shell',
     'file_size':
-        9162616,
+        9464288,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/android-x64/trace_processor_shell',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/android-x64/trace_processor_shell',
     'sha256':
-        '2cc5a02270a28db52aa17bfafcf215e3d754a936de595186a7152535ab28531b'
+        'fb54ee018ca1d4895ad3e1192e2e585a3709b58864ef3beab4368af3ae17e5fb'
 }, {
     'arch':
         'windows-amd64',
     'file_name':
         'trace_processor_shell.exe',
     'file_size':
-        8790016,
+        9548288,
     'url':
-        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v37.0/windows-amd64/trace_processor_shell.exe',
+        'https://commondatastorage.googleapis.com/perfetto-luci-artifacts/v46.0/windows-amd64/trace_processor_shell.exe',
     'sha256':
-        'e3193141bcb8bcc35b47c3ee8126d1f3ebe1b54a9ecde59ade9db4f22c6f77d6',
+        '41a3353caf59d4df14e7d5ba185861fdc8e41776c1720a6fc1eddc6a99afb6c0',
     'platform':
         'win32',
     'machine': ['amd64']
@@ -210,6 +210,7 @@ The intended usage is:
 import hashlib
 import os
 import platform
+import random
 import subprocess
 import sys
 
@@ -236,9 +237,10 @@ def download_or_get_cached(file_name, url, sha256):
       if digest == sha256:
         needs_download = False
 
-  if needs_download:
-    # Either the filed doesn't exist or the SHA256 doesn't match.
-    tmp_path = bin_path + '.tmp'
+  if needs_download:  # The file doesn't exist or the SHA256 doesn't match.
+    # Use a unique random file to guard against concurrent executions.
+    # See https://github.com/google/perfetto/issues/786 .
+    tmp_path = '%s.%d.tmp' % (bin_path, random.randint(0, 100000))
     print('Downloading ' + url)
     subprocess.check_call(['curl', '-f', '-L', '-#', '-o', tmp_path, url])
     with open(tmp_path, 'rb') as fd:
@@ -248,8 +250,9 @@ def download_or_get_cached(file_name, url, sha256):
                       (url, actual_sha256, sha256))
     os.chmod(tmp_path, 0o755)
     os.replace(tmp_path, bin_path)
-    with open(sha256_path, 'w') as f:
+    with open(tmp_path, 'w') as f:
       f.write(sha256)
+    os.replace(tmp_path, sha256_path)
   return bin_path
 
 
diff --git a/tests/test_viewer.py b/tests/test_viewer.py
index 12b9d88b..9af7acd1 100644
--- a/tests/test_viewer.py
+++ b/tests/test_viewer.py
@@ -17,6 +17,7 @@
 import urllib.request
 import webbrowser
 
+import viztracer
 from viztracer.viewer import viewer_main
 
 from .cmdline_tmpl import CmdlineTmpl
@@ -230,6 +231,23 @@ def test_use_external_processor(self):
         finally:
             os.remove(f.name)
 
+    def test_external_processor_version(self):
+        root_path = os.path.dirname(viztracer.__file__)
+        web_dist_path = os.path.join(root_path, "web_dist")
+        for path in os.listdir(web_dist_path):
+            # match the version number in the file name (v47.0-deadbeef)
+            if (match := re.match(r"v(\d+\.\d+)-[0-9a-f]+$", path)) is not None:
+                perfetto_version = match.group(1)
+                with open(os.path.join(web_dist_path, "trace_processor")) as f:
+                    match = re.search(r"tools/roll-prebuilts v(\d+\.\d+)", f.read())
+                if match is None:
+                    self.fail("Can't find perfetto version in trace_processor")
+                processor_version = match.group(1)
+                # The trace processor version is usually a version before the perfetto version
+                # So we allow a 1.0 difference
+                self.assertAlmostEqual(float(perfetto_version), float(processor_version), delta=1.0)
+                break
+
     @unittest.skipIf(sys.platform == "win32", "Can't send Ctrl+C reliably on Windows")
     def test_port_in_use_error(self):
         json_script = '{"file_info": {}, "traceEvents": []}'