diff --git a/docker/test/performance-comparison/compare.sh b/docker/test/performance-comparison/compare.sh
index 364e9994ab7..0b678024765 100755
--- a/docker/test/performance-comparison/compare.sh
+++ b/docker/test/performance-comparison/compare.sh
@@ -121,7 +121,7 @@ function run_tests
     then
         # Use the explicitly set path to directory with test files.
         test_prefix="$CHPC_TEST_PATH"
-    elif [ "$PR_TO_TEST" = "0" ]
+    elif [ "$PR_TO_TEST" == "0" ]
     then
         # When testing commits from master, use the older test files. This
         # allows the tests to pass even when we add new functions and tests for
@@ -155,6 +155,20 @@ function run_tests
         test_files=$(ls "$test_prefix"/*.xml)
     fi
 
+    # For PRs, test only a subset of queries, and run them less times.
+    # If the corresponding environment variables are already set, keep
+    # those values.
+    if [ "$PR_TO_TEST" == "0" ]
+    then
+        CHPC_TEST_RUNS=${CHPC_RUNS:-7}
+        CHPC_MAX_QUERIES=${CHPC_MAX_QUERIES:-15}
+    else
+        CHPC_TEST_RUNS=${CHPC_RUNS:-13}
+        CHPC_MAX_QUERIES=${CHPC_MAX_QUERIES:-0}
+    fi
+    export CHPC_TEST_RUNS
+    export CHPC_MAX_QUERIES
+
     # Determine which concurrent benchmarks to run. For now, the only test
     # we run as a concurrent benchmark is 'website'. Run it as benchmark if we
     # are also going to run it as a normal test.
@@ -187,6 +201,7 @@ function run_tests
         # the grep is to filter out set -x output and keep only time output
         { \
             time "$script_dir/perf.py" --host localhost localhost --port 9001 9002 \
+                --runs "$CHPC_RUNS" --max-queries "$CHPC_MAX_QUERIES" \
                 -- "$test" > "$test_name-raw.tsv" 2> "$test_name-err.log" ; \
         } 2>&1 >/dev/null | grep -v ^+ >> "wall-clock-times.tsv" \
             || echo "Test $test_name failed with error code $?" >> "$test_name-err.log"
diff --git a/docker/test/performance-comparison/perf.py b/docker/test/performance-comparison/perf.py
index e1476d9aeb4..64314c129b5 100755
--- a/docker/test/performance-comparison/perf.py
+++ b/docker/test/performance-comparison/perf.py
@@ -7,6 +7,7 @@ import clickhouse_driver
 import xml.etree.ElementTree as et
 import argparse
 import pprint
+import random
 import re
 import string
 import time
@@ -20,7 +21,8 @@ parser = argparse.ArgumentParser(description='Run performance test.')
 parser.add_argument('file', metavar='FILE', type=argparse.FileType('r', encoding='utf-8'), nargs=1, help='test description file')
 parser.add_argument('--host', nargs='*', default=['localhost'], help="Server hostname(s). Corresponds to '--port' options.")
 parser.add_argument('--port', nargs='*', default=[9000], help="Server port(s). Corresponds to '--host' options.")
-parser.add_argument('--runs', type=int, default=int(os.environ.get('CHPC_RUNS', 13)), help='Number of query runs per server. Defaults to CHPC_RUNS environment variable.')
+parser.add_argument('--runs', type=int, default=1, help='Number of query runs per server.')
+parser.add_argument('--max-queries', type=int, default=None, help='Test no more than this number of queries, chosen at random.')
 parser.add_argument('--long', action='store_true', help='Do not skip the tests tagged as long.')
 parser.add_argument('--print-queries', action='store_true', help='Print test queries and exit.')
 parser.add_argument('--print-settings', action='store_true', help='Print test settings and exit.')
@@ -189,8 +191,14 @@ for conn_index, c in enumerate(connections):
         c.execute(q)
         print(f'fill\t{conn_index}\t{c.last_query.elapsed}\t{tsv_escape(q)}')
 
+# Run the queries in randomized order, but preserve their indexes as specified
+# in the test XML. To avoid using too much time, limit the number of queries
+# we run per test.
+queries_to_run = random.sample(range(0, len(test_queries)), args.max_queries or len(test_queries))
+
 # Run test queries.
-for query_index, q in enumerate(test_queries):
+for query_index in queries_to_run:
+    q = test_queries[query_index]
     query_prefix = f'{test_name}.query{query_index}'
 
     # We have some crazy long queries (about 100kB), so trim them to a sane