A better fix for #67476

Throw an exception instead of silently ignoring two conflicting settings.

src/Common/ErrorCodes.cpp

@@ -609,6 +609,7 @@
     M(728, UNEXPECTED_DATA_TYPE) \
     M(729, ILLEGAL_TIME_SERIES_TAGS) \
     M(730, REFRESH_FAILED) \
+    M(731, QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE) \
     \
     M(900, DISTRIBUTED_CACHE_ERROR) \
     M(901, CANNOT_USE_DISTRIBUTED_CACHE) \

src/Interpreters/executeQuery.cpp

@@ -99,6 +99,7 @@ namespace DB
 namespace ErrorCodes
 {
     extern const int QUERY_CACHE_USED_WITH_NONDETERMINISTIC_FUNCTIONS;
+    extern const int QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE;
     extern const int QUERY_CACHE_USED_WITH_SYSTEM_TABLE;
     extern const int INTO_OUTFILE_NOT_ALLOWED;
     extern const int INVALID_TRANSACTION;
@@ -1118,22 +1119,24 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
             && settings.use_query_cache
             && !internal
             && client_info.query_kind == ClientInfo::QueryKind::INITIAL_QUERY
-            /// Bug 67476: Avoid that the query cache stores truncated results if the query ran with a non-THROW overflow mode and hit a limit.
-            /// This is more workaround than a fix ... unfortunately it is hard to detect from the perspective of the query cache that the
-            /// query result is truncated.
-            && (settings.read_overflow_mode == OverflowMode::THROW
-                && settings.read_overflow_mode_leaf == OverflowMode::THROW
-                && settings.group_by_overflow_mode == OverflowMode::THROW
-                && settings.sort_overflow_mode == OverflowMode::THROW
-                && settings.result_overflow_mode == OverflowMode::THROW
-                && settings.timeout_overflow_mode == OverflowMode::THROW
-                && settings.set_overflow_mode == OverflowMode::THROW
-                && settings.join_overflow_mode == OverflowMode::THROW
-                && settings.transfer_overflow_mode == OverflowMode::THROW
-                && settings.distinct_overflow_mode == OverflowMode::THROW)
             && (ast->as<ASTSelectQuery>() || ast->as<ASTSelectWithUnionQuery>());
         QueryCache::Usage query_cache_usage = QueryCache::Usage::None;
 
+        /// Bug 67476: If the query runs with a non-THROW overflow mode and hits a limit, the query cache will store a truncated result (if
+        /// enabled). This is incorrect. Unfortunately it is hard to detect from the perspective of the query cache that the query result
+        /// is truncated. Therefore throw an exception, to notify the user to disable either the query cache or use another overflow mode.
+        if (settings.use_query_cache && (settings.read_overflow_mode != OverflowMode::THROW
+            || settings.read_overflow_mode_leaf != OverflowMode::THROW
+            || settings.group_by_overflow_mode != OverflowMode::THROW
+            || settings.sort_overflow_mode != OverflowMode::THROW
+            || settings.result_overflow_mode != OverflowMode::THROW
+            || settings.timeout_overflow_mode != OverflowMode::THROW
+            || settings.set_overflow_mode != OverflowMode::THROW
+            || settings.join_overflow_mode != OverflowMode::THROW
+            || settings.transfer_overflow_mode != OverflowMode::THROW
+            || settings.distinct_overflow_mode != OverflowMode::THROW))
+            throw Exception(ErrorCodes::QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE, "use_query_cache and overflow_mode != 'throw' cannot be used together");
+
         /// If the query runs with "use_query_cache = 1", we first probe if the query cache already contains the query result (if yes:
         /// return result from cache). If doesn't, we execute the query normally and write the result into the query cache. Both steps use a
         /// hash of the AST, the current database and the settings as cache key. Unfortunately, the settings are in some places internally

tests/queries/0_stateless/02494_query_cache_bugs.reference

@@ -23,23 +23,3 @@ Row 1:
 x: 1
 2
 -- Bug 67476: Queries with overflow mode != throw must not be cached by the query cache
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0
-0

tests/queries/0_stateless/02494_query_cache_bugs.sql

@@ -43,25 +43,15 @@ DROP TABLE IF EXISTS tab;
 CREATE TABLE tab(c UInt64) ENGINE = Memory;
 
 SYSTEM DROP QUERY CACHE;
-SELECT sum(c) FROM tab SETTINGS read_overflow_mode = 'break', use_query_cache = 1;
+SELECT sum(c) FROM tab SETTINGS read_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT count(*) from system.query_cache;
+SELECT sum(c) FROM tab SETTINGS read_overflow_mode_leaf = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT sum(c) FROM tab SETTINGS read_overflow_mode_leaf = 'break', use_query_cache = 1;
+SELECT sum(c) FROM tab SETTINGS group_by_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT count(*) from system.query_cache;
+SELECT sum(c) FROM tab SETTINGS sort_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT sum(c) FROM tab SETTINGS group_by_overflow_mode = 'break', use_query_cache = 1;
+SELECT sum(c) FROM tab SETTINGS result_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT count(*) from system.query_cache;
+SELECT sum(c) FROM tab SETTINGS timeout_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT sum(c) FROM tab SETTINGS sort_overflow_mode = 'break', use_query_cache = 1;
+SELECT sum(c) FROM tab SETTINGS set_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT count(*) from system.query_cache;
+SELECT sum(c) FROM tab SETTINGS join_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT sum(c) FROM tab SETTINGS result_overflow_mode = 'break', use_query_cache = 1;
+SELECT sum(c) FROM tab SETTINGS transfer_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT count(*) from system.query_cache;
+SELECT sum(c) FROM tab SETTINGS distinct_overflow_mode = 'break', use_query_cache = 1; -- { serverError QUERY_CACHE_USED_WITH_NON_THROW_OVERFLOW_MODE }
-SELECT sum(c) FROM tab SETTINGS timeout_overflow_mode = 'break', use_query_cache = 1;
-SELECT count(*) from system.query_cache;
-SELECT sum(c) FROM tab SETTINGS set_overflow_mode = 'break', use_query_cache = 1;
-SELECT count(*) from system.query_cache;
-SELECT sum(c) FROM tab SETTINGS join_overflow_mode = 'break', use_query_cache = 1;
-SELECT count(*) from system.query_cache;
-SELECT sum(c) FROM tab SETTINGS transfer_overflow_mode = 'break', use_query_cache = 1;
-SELECT count(*) from system.query_cache;
-SELECT sum(c) FROM tab SETTINGS distinct_overflow_mode = 'break', use_query_cache = 1;
-SELECT count(*) from system.query_cache;
 
 SYSTEM DROP QUERY CACHE;