Merge pull request #56519 from rschu1ze/qc-ignore-nondeterministic-queries

Query cache: Allow to ignore non-deterministic queries

docs/en/operations/query-cache.md

@@ -169,7 +169,12 @@ Also, results of queries with non-deterministic functions are not cached by defa
   [`getMacro()`](../sql-reference/functions/other-functions.md#getMacro) etc.
 
 To force caching of results of queries with non-deterministic functions regardless, use setting
-[query_cache_store_results_of_queries_with_nondeterministic_functions](settings/settings.md#query-cache-store-results-of-queries-with-nondeterministic-functions).
+[query_cache_nondeterministic_function_handling](settings/settings.md#query-cache-nondeterministic-function-handling).
+
+:::note
+Prior to ClickHouse v23.11, setting 'query_cache_store_results_of_queries_with_nondeterministic_functions = 0 / 1' controlled whether
+results of queries with non-deterministic results were cached. In newer ClickHouse versions, this setting is obsolete and has no effect.
+:::
 
 Finally, entries in the query cache are not shared between users due to security reasons. For example, user A must not be able to bypass a
 row policy on a table by running the same query as another user B for whom no such policy exists. However, if necessary, cache entries can

docs/en/operations/settings/settings.md

@@ -1657,16 +1657,17 @@ Possible values:
 
 Default value: `1`.
 
-## query_cache_store_results_of_queries_with_nondeterministic_functions {#query-cache-store-results-of-queries-with-nondeterministic-functions}
+## query_cache_nondeterministic_function_handling {#query-cache-nondeterministic-function-handling}
 
-If turned on, then results of `SELECT` queries with non-deterministic functions (e.g. `rand()`, `now()`) can be cached in the [query cache](../query-cache.md).
+Controls how the [query cache](../query-cache.md) handles `SELECT` queries with non-deterministic functions like `rand()` or `now()`.
 
 Possible values:
 
-- 0 - Disabled
+- `'throw'` - Throw an exception and don't cache the query result.
-- 1 - Enabled
+- `'save'` - Cache the query result.
+- `'ignore'` - Don't cache the query result and don't throw an exception.
 
-Default value: `0`.
+Default value: `throw`.
 
 ## query_cache_min_query_runs {#query-cache-min-query-runs}
 

docs/en/sql-reference/functions/date-time-functions.md

@@ -1381,7 +1381,7 @@ toStartOfFifteenMinutes(toDateTime('2023-04-21 10:20:00')): 2023-04-21 10:15:00
 toStartOfFifteenMinutes(toDateTime('2023-04-21 10:23:00')): 2023-04-21 10:15:00
 ```
 
-## toStartOfInterval(time_or_data, INTERVAL x unit \[, time_zone\])
+## toStartOfInterval(date_or_date_with_time, INTERVAL x unit \[, time_zone\])
 
 This function generalizes other `toStartOf*()` functions. For example,
 - `toStartOfInterval(t, INTERVAL 1 year)` returns the same as `toStartOfYear(t)`,

src/Common/ErrorCodes.cpp

@@ -583,7 +583,7 @@
     M(701, CLUSTER_DOESNT_EXIST) \
     M(702, CLIENT_INFO_DOES_NOT_MATCH) \
     M(703, INVALID_IDENTIFIER) \
-    M(704, CANNOT_USE_QUERY_CACHE_WITH_NONDETERMINISTIC_FUNCTIONS) \
+    M(704, QUERY_CACHE_USED_WITH_NONDETERMINISTIC_FUNCTIONS) \
     M(705, TABLE_NOT_EMPTY) \
     M(706, LIBSSH_ERROR) \
     M(999, KEEPER_EXCEPTION) \

src/Core/Settings.h

@@ -617,7 +617,7 @@ class IColumn;
     M(Bool, use_query_cache, false, "Enable the query cache", 0) \
     M(Bool, enable_writes_to_query_cache, true, "Enable storing results of SELECT queries in the query cache", 0) \
     M(Bool, enable_reads_from_query_cache, true, "Enable reading results of SELECT queries from the query cache", 0) \
-    M(Bool, query_cache_store_results_of_queries_with_nondeterministic_functions, false, "Store results of queries with non-deterministic functions (e.g. rand(), now()) in the query cache", 0) \
+    M(QueryCacheNondeterministicFunctionHandling, query_cache_nondeterministic_function_handling, QueryCacheNondeterministicFunctionHandling::Throw, "How the query cache handles queries with non-deterministic functions, e.g. now()", 0) \
     M(UInt64, query_cache_max_size_in_bytes, 0, "The maximum amount of memory (in bytes) the current user may allocate in the query cache. 0 means unlimited. ", 0) \
     M(UInt64, query_cache_max_entries, 0, "The maximum number of query results the current user may store in the query cache. 0 means unlimited.", 0) \
     M(UInt64, query_cache_min_query_runs, 0, "Minimum number a SELECT query must run before its result is stored in the query cache", 0) \
@@ -876,6 +876,7 @@ class IColumn;
     MAKE_OBSOLETE(M, Bool, optimize_duplicate_order_by_and_distinct, false) \
     MAKE_OBSOLETE(M, UInt64, parallel_replicas_min_number_of_granules_to_enable, 0) \
     MAKE_OBSOLETE(M, Bool, query_plan_optimize_projection, true) \
+    MAKE_OBSOLETE(M, Bool, query_cache_store_results_of_queries_with_nondeterministic_functions, false) \
 
     /** The section above is for obsolete settings. Do not add anything there. */
 

src/Core/SettingsEnums.cpp

@@ -69,6 +69,12 @@ IMPLEMENT_SETTING_ENUM(DistributedProductMode, ErrorCodes::UNKNOWN_DISTRIBUTED_P
      {"allow",  DistributedProductMode::ALLOW}})
 
 
+IMPLEMENT_SETTING_ENUM(QueryCacheNondeterministicFunctionHandling, ErrorCodes::BAD_ARGUMENTS,
+    {{"throw",  QueryCacheNondeterministicFunctionHandling::Throw},
+     {"save",   QueryCacheNondeterministicFunctionHandling::Save},
+     {"ignore", QueryCacheNondeterministicFunctionHandling::Ignore}})
+
+
 IMPLEMENT_SETTING_ENUM(DateTimeInputFormat, ErrorCodes::BAD_ARGUMENTS,
     {{"basic",       FormatSettings::DateTimeInputFormat::Basic},
      {"best_effort", FormatSettings::DateTimeInputFormat::BestEffort},

src/Core/SettingsEnums.h

@@ -70,6 +70,16 @@ enum class DistributedProductMode
 
 DECLARE_SETTING_ENUM(DistributedProductMode)
 
+/// How the query cache handles queries with non-deterministic functions, e.g. now()
+enum class QueryCacheNondeterministicFunctionHandling
+{
+    Throw,
+    Save,
+    Ignore
+};
+
+DECLARE_SETTING_ENUM(QueryCacheNondeterministicFunctionHandling)
+
 
 DECLARE_SETTING_ENUM_WITH_RENAME(DateTimeInputFormat, FormatSettings::DateTimeInputFormat)
 

src/Interpreters/executeQuery.cpp

@@ -96,7 +96,7 @@ namespace DB
 
 namespace ErrorCodes
 {
-    extern const int CANNOT_USE_QUERY_CACHE_WITH_NONDETERMINISTIC_FUNCTIONS;
+    extern const int QUERY_CACHE_USED_WITH_NONDETERMINISTIC_FUNCTIONS;
     extern const int INTO_OUTFILE_NOT_ALLOWED;
     extern const int INVALID_TRANSACTION;
     extern const int LOGICAL_ERROR;
@@ -1106,32 +1106,41 @@ static std::tuple<ASTPtr, BlockIO> executeQueryImpl(
                     /// top of the pipeline which stores the result in the query cache.
                     if (can_use_query_cache && settings.enable_writes_to_query_cache)
                     {
-                        if (astContainsNonDeterministicFunctions(ast, context) && !settings.query_cache_store_results_of_queries_with_nondeterministic_functions)
+                        const bool ast_contains_nondeterministic_functions = astContainsNonDeterministicFunctions(ast, context);
-                            throw Exception(ErrorCodes::CANNOT_USE_QUERY_CACHE_WITH_NONDETERMINISTIC_FUNCTIONS,
+                        const QueryCacheNondeterministicFunctionHandling nondeterministic_function_handling = settings.query_cache_nondeterministic_function_handling;
-                                "Unable to cache the query result because the query contains a non-deterministic function. Use setting `query_cache_store_results_of_queries_with_nondeterministic_functions = 1` to cache the query result regardless");
 
-                        QueryCache::Key key(
+                        if (ast_contains_nondeterministic_functions && nondeterministic_function_handling == QueryCacheNondeterministicFunctionHandling::Throw)
-                            ast, res.pipeline.getHeader(),
+                            throw Exception(ErrorCodes::QUERY_CACHE_USED_WITH_NONDETERMINISTIC_FUNCTIONS,
-                            context->getUserName(), settings.query_cache_share_between_users,
+                                "The query result was not cached because the query contains a non-deterministic function."
-                            std::chrono::system_clock::now() + std::chrono::seconds(settings.query_cache_ttl),
+                                " Use setting `query_cache_nondeterministic_function_handling = 'save'` or `= 'ignore'` to cache the query result regardless or to omit caching");
-                            settings.query_cache_compress_entries);
 
-                        const size_t num_query_runs = query_cache->recordQueryRun(key);
+                        if (!ast_contains_nondeterministic_functions || nondeterministic_function_handling == QueryCacheNondeterministicFunctionHandling::Save)
-                        if (num_query_runs <= settings.query_cache_min_query_runs)
                         {
-                            LOG_TRACE(&Poco::Logger::get("QueryCache"), "Skipped insert because the query ran {} times but the minimum required number of query runs to cache the query result is {}", num_query_runs, settings.query_cache_min_query_runs);
+                            QueryCache::Key key(
-                        }
+                                ast, res.pipeline.getHeader(),
-                        else
+                                context->getUserName(), settings.query_cache_share_between_users,
-                        {
+                                std::chrono::system_clock::now() + std::chrono::seconds(settings.query_cache_ttl),
-                            auto query_cache_writer = std::make_shared<QueryCache::Writer>(query_cache->createWriter(
+                                settings.query_cache_compress_entries);
-                                             key,
+
-                                             std::chrono::milliseconds(settings.query_cache_min_query_duration.totalMilliseconds()),
+                            const size_t num_query_runs = query_cache->recordQueryRun(key);
-                                             settings.query_cache_squash_partial_results,
+                            if (num_query_runs <= settings.query_cache_min_query_runs)
-                                             settings.max_block_size,
+                            {
-                                             settings.query_cache_max_size_in_bytes,
+                                LOG_TRACE(&Poco::Logger::get("QueryCache"),
-                                             settings.query_cache_max_entries));
+                                        "Skipped insert because the query ran {} times but the minimum required number of query runs to cache the query result is {}",
-                            res.pipeline.writeResultIntoQueryCache(query_cache_writer);
+                                        num_query_runs, settings.query_cache_min_query_runs);
-                            query_cache_usage = QueryCache::Usage::Write;
+                            }
+                            else
+                            {
+                                auto query_cache_writer = std::make_shared<QueryCache::Writer>(query_cache->createWriter(
+                                                 key,
+                                                 std::chrono::milliseconds(settings.query_cache_min_query_duration.totalMilliseconds()),
+                                                 settings.query_cache_squash_partial_results,
+                                                 settings.max_block_size,
+                                                 settings.query_cache_max_size_in_bytes,
+                                                 settings.query_cache_max_entries));
+                                res.pipeline.writeResultIntoQueryCache(query_cache_writer);
+                                query_cache_usage = QueryCache::Usage::Write;
+                            }
                         }
                     }
 

tests/queries/0_stateless/02494_query_cache_nondeterministic_functions.reference

@@ -1,4 +1,8 @@
+-- query_cache_nondeterministic_function_handling = throw
 0
----
+-- query_cache_nondeterministic_function_handling = save
 1
 1
+-- query_cache_nondeterministic_function_handling = ignore
+1
+0

tests/queries/0_stateless/02494_query_cache_nondeterministic_functions.sql

@@ -3,14 +3,21 @@
 
 SYSTEM DROP QUERY CACHE;
 
--- rand() is non-deterministic, the query is rejected by default
+SELECT '-- query_cache_nondeterministic_function_handling = throw';
-SELECT COUNT(rand(1)) SETTINGS use_query_cache = true; -- { serverError CANNOT_USE_QUERY_CACHE_WITH_NONDETERMINISTIC_FUNCTIONS }
+SELECT count(now()) SETTINGS use_query_cache = true; -- { serverError QUERY_CACHE_USED_WITH_NONDETERMINISTIC_FUNCTIONS }
-SELECT COUNT(*) FROM system.query_cache;
+SELECT count(now()) SETTINGS use_query_cache = true, query_cache_nondeterministic_function_handling = 'throw'; -- { serverError QUERY_CACHE_USED_WITH_NONDETERMINISTIC_FUNCTIONS }
-
+SELECT count(*) FROM system.query_cache;
-SELECT '---';
+
-
+SYSTEM DROP QUERY CACHE;
--- Force caching using a setting
+
-SELECT COUNT(RAND(1)) SETTINGS use_query_cache = true, query_cache_store_results_of_queries_with_nondeterministic_functions = true;
+SELECT '-- query_cache_nondeterministic_function_handling = save';
-SELECT COUNT(*) FROM system.query_cache;
+SELECT count(now()) SETTINGS use_query_cache = true, query_cache_nondeterministic_function_handling = 'save';
+SELECT count(*) FROM system.query_cache;
+
+SYSTEM DROP QUERY CACHE;
+
+SELECT '-- query_cache_nondeterministic_function_handling = ignore';
+SELECT count(now()) SETTINGS use_query_cache = true, query_cache_nondeterministic_function_handling = 'ignore';
+SELECT count(*) FROM system.query_cache;
 
 SYSTEM DROP QUERY CACHE;

tests/queries/0_stateless/02888_obsolete_settings.reference

@@ -42,6 +42,7 @@ optimize_duplicate_order_by_and_distinct
 optimize_fuse_sum_count_avg
 parallel_replicas_min_number_of_granules_to_enable
 partial_merge_join_optimizations
+query_cache_store_results_of_queries_with_nondeterministic_functions
 query_plan_optimize_projection
 replication_alter_columns_timeout
 restore_threads