diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6b3416e34..8e0f77d62 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 - Fix not logging OpenAPI queries when `log-query=main-query` is enabled by @steve-chavez in #4226
 - Fix not logging explain query when `log-query=main-query` is enabled by @steve-chavez in #4319
+- Fix not logging transaction variables and db-pre-request function when `log-query=main-query` is enabled by @steve-chavez in #3934
 
 ### Added
 
diff --git a/src/PostgREST/Logger.hs b/src/PostgREST/Logger.hs
index c091b8026..93d441296 100644
--- a/src/PostgREST/Logger.hs
+++ b/src/PostgREST/Logger.hs
@@ -123,7 +123,7 @@ logWithZTime loggerState txt = do
 
 logMainQ :: LoggerState -> MainQuery -> IO ()
 logMainQ loggerState MainQuery{mqOpenAPI=(x, y, z),..} =
-  let snipts  = renderSnippet <$> [mqMain, x, y, z, fromMaybe mempty mqExplain]
+  let snipts  = renderSnippet <$> [mqTxVars, fromMaybe mempty mqPreReq, mqMain, x, y, z, fromMaybe mempty mqExplain]
       -- Does not log SQL when it's empty (happens on OPTIONS requests and when the openapi queries are not generated)
       logQ q = when (q /= mempty) $ logWithZTime loggerState $ showOnSingleLine '\n' $ T.decodeUtf8 q in
   mapM_ logQ snipts
diff --git a/test/io/__snapshots__/test_cli/test_schema_cache_snapshot[dbRoutines].yaml b/test/io/__snapshots__/test_cli/test_schema_cache_snapshot[dbRoutines].yaml
index 55ed52b7f..ff0102673 100644
--- a/test/io/__snapshots__/test_cli/test_schema_cache_snapshot[dbRoutines].yaml
+++ b/test/io/__snapshots__/test_cli/test_schema_cache_snapshot[dbRoutines].yaml
@@ -196,6 +196,23 @@
       pdSchema: public
       pdVolatility: Volatile
 
+- - qiName: do_nothing
+    qiSchema: public
+  - - pdDescription: null
+      pdFuncSettings: []
+      pdHasVariadic: false
+      pdName: do_nothing
+      pdParams: []
+      pdReturnType:
+        contents:
+          contents:
+            qiName: void
+            qiSchema: pg_catalog
+          tag: Scalar
+        tag: Single
+      pdSchema: public
+      pdVolatility: Volatile
+
 - - qiName: get_guc_value
     qiSchema: public
   - - pdDescription: null
diff --git a/test/io/fixtures.sql b/test/io/fixtures.sql
index c50f15e7f..0aeeb1a3c 100644
--- a/test/io/fixtures.sql
+++ b/test/io/fixtures.sql
@@ -95,6 +95,9 @@ create function notify_do_nothing() returns void as $_$
   notify pgrst, 'nothing';
 $_$ language sql;
 
+create function do_nothing() returns void as $_$
+$_$ language sql;
+
 create function reset_invalid_role_claim_key() returns void as $_$
 begin
   alter role postgrest_test_authenticator reset pgrst.jwt_role_claim_key;
diff --git a/test/io/test_io.py b/test/io/test_io.py
index 2b4c2ba99..a7f0bf70d 100644
--- a/test/io/test_io.py
+++ b/test/io/test_io.py
@@ -1003,7 +1003,20 @@ def test_log_level(level, defaultenv):
 def test_log_query(level, defaultenv):
     "log_query=true should log the SQL query according to the log_level"
 
-    env = {**defaultenv, "PGRST_LOG_LEVEL": level, "PGRST_LOG_QUERY": "main-query"}
+    def drain_stdout(proc):
+        lines = []
+        while True:
+            chunk = proc.read_stdout(nlines=20)
+            if not chunk:
+                break
+            lines.extend(chunk)
+        return lines
+
+    env = {
+        **defaultenv,
+        "PGRST_LOG_LEVEL": level,
+        "PGRST_LOG_QUERY": "main-query",
+    }
 
     with run(env=env) as postgrest:
         response = postgrest.session.get("/")
@@ -1033,15 +1046,9 @@ def test_log_query(level, defaultenv):
         root_tables_regx = r".+: SELECT   n.nspname AS table_schema, .+ FROM pg_class c .+ ORDER BY table_schema, table_name"
         root_procs_regx = r".+: WITH base_types AS \(.+\) SELECT   pn.nspname AS proc_schema, .+ FROM pg_proc p.+AND p.pronamespace = \$1::regnamespace"
         root_descr_regx = r".+: SELECT pg_catalog\.obj_description\(\$1::regnamespace, 'pg_namespace'\)"
-
-        def drain_stdout(proc):
-            lines = []
-            while True:
-                chunk = proc.read_stdout(nlines=20)
-                if not chunk:
-                    break
-                lines.extend(chunk)
-            return lines
+        set_config_regx = (
+            r".+: select set_config\('search_path', \$1, true\), set_config\("
+        )
 
         output = drain_stdout(postgrest)
 
@@ -1053,8 +1060,10 @@ def test_log_query(level, defaultenv):
         root_tables = [line for line in output if re.match(root_tables_regx, line)]
         root_procs = [line for line in output if re.match(root_procs_regx, line)]
         root_descr = [line for line in output if re.match(root_descr_regx, line)]
+        set_configs = [line for line in output if re.match(set_config_regx, line)]
 
         if level == "crit":
+            assert not set_configs
             assert not project_queries
             assert not project_counts
             assert not infinite_queries
@@ -1062,6 +1071,7 @@ def test_log_query(level, defaultenv):
             assert not root_procs
             assert not root_descr
         elif level in {"error", "warn"}:
+            assert len(set_configs) == 1
             assert len(infinite_queries) == 1
             assert not project_queries
             assert not project_counts
@@ -1069,6 +1079,7 @@ def test_log_query(level, defaultenv):
             assert not root_procs
             assert not root_descr
         elif level == "info":
+            assert len(set_configs) == 5
             assert len(project_queries) == 3
             assert len(project_counts) == 2
             assert len(infinite_queries) == 1
@@ -1076,6 +1087,7 @@ def test_log_query(level, defaultenv):
             assert len(root_procs) == 1
             assert len(root_descr) == 1
         elif level == "debug":
+            assert len(set_configs) == 5
             assert len(project_queries) == 3
             assert len(project_counts) == 2
             assert len(infinite_queries) == 1
@@ -1083,6 +1095,29 @@ def test_log_query(level, defaultenv):
             assert len(root_procs) == 1
             assert len(root_descr) == 1
 
+    pre_req_env = {
+        **env,
+        "PGRST_DB_PRE_REQUEST": "do_nothing",
+    }
+
+    with run(env=pre_req_env) as postgrest:
+        response = postgrest.session.get("/projects")
+        assert response.status_code == 200
+
+        output = drain_stdout(postgrest)
+
+        pre_request_regx = r'.+: select "do_nothing"()'
+        pre_reqs = [line for line in output if re.match(pre_request_regx, line)]
+
+        if level == "crit":
+            assert not pre_reqs
+        elif level in {"error", "warn"}:
+            assert not pre_reqs
+        elif level == "info":
+            assert len(pre_reqs) == 1
+        elif level == "debug":
+            assert len(pre_reqs) == 1
+
 
 def test_no_pool_connection_required_on_bad_http_logic(defaultenv):
     "no pool connection should be consumed for failing on invalid http logic"
diff --git a/test/spec/fixtures/schema.sql b/test/spec/fixtures/schema.sql
index e9e1e70ac..19167867b 100644
--- a/test/spec/fixtures/schema.sql
+++ b/test/spec/fixtures/schema.sql
@@ -3843,3 +3843,6 @@ $$ language sql;
 create or replace function test.delete_items_returns_void() returns void as $$
   delete from items;
 $$ language sql;
+
+create function do_nothing() returns void as $_$
+$_$ language sql;