Merge pull request ClickHouse#79460 from ClickHouse/add-a-setting-to-better-configure-fs-cache-size

Add fs cache setting `max_size_ratio_to_total_space`

Author: kssenii

src/Interpreters/Cache/FileCacheSettings.cpp

@@ -6,6 +6,7 @@
 #include <Common/Exception.h>
 #include <Common/NamedCollections/NamedCollections.h>
 #include <Common/logger_useful.h>
+#include <Common/filesystemHelpers.h>
 #include <Storages/System/MutableColumnsAndConstraints.h>
 #include <Interpreters/Cache/FileCache.h>
 #include <DataTypes/DataTypeString.h>
@@ -46,7 +47,8 @@ namespace ErrorCodes
     DECLARE(Bool, enable_bypass_cache_with_threshold, false, "Undocumented. Not recommended for use", 0) \
     DECLARE(UInt64, bypass_cache_threshold, FILECACHE_BYPASS_THRESHOLD, "Undocumented. Not recommended for use", 0) \
     DECLARE(Bool, write_cache_per_user_id_directory, false, "Internal ClickHouse Cloud setting", 0) \
-    DECLARE(Bool, allow_dynamic_cache_resize, false, "Allow dynamic resize of filesystem cache", 0)
+    DECLARE(Bool, allow_dynamic_cache_resize, false, "Allow dynamic resize of filesystem cache", 0) \
+    DECLARE(Double, max_size_ratio_to_total_space, 0, "Ratio of `max_size` to total disk space", 0) \
 
 DECLARE_SETTINGS_TRAITS(FileCacheSettingsTraits, LIST_OF_FILE_CACHE_SETTINGS)
 IMPLEMENT_SETTINGS_TRAITS(FileCacheSettingsTraits, LIST_OF_FILE_CACHE_SETTINGS)
@@ -157,7 +159,10 @@ void FileCacheSettings::dumpToSystemSettingsColumns(
     res_columns[i++]->insert(cache->getFileSegmentsNum());
 }
 
-void FileCacheSettings::loadFromConfig(const Poco::Util::AbstractConfiguration & config, const std::string & config_prefix, bool allow_empty_path)
+void FileCacheSettings::loadFromConfig(
+    const Poco::Util::AbstractConfiguration & config,
+    const std::string & config_prefix,
+    const std::string & default_cache_path)
 {
     if (!config.has(config_prefix))
         throw Exception(ErrorCodes::NO_ELEMENTS_IN_CONFIG, "There is no path '{}' in configuration file.", config_prefix);
@@ -177,7 +182,10 @@ void FileCacheSettings::loadFromConfig(const Poco::Util::AbstractConfiguration &
     boost::to_upper(cache_policy);
     (*this)[FileCacheSetting::cache_policy] = cache_policy;
 
-    validate(allow_empty_path);
+    if (!(*this)[FileCacheSetting::path].changed)
+        (*this)[FileCacheSetting::path] = default_cache_path;
+
+    validate();
 }
 
 void FileCacheSettings::loadFromCollection(const NamedCollection & collection)
@@ -194,15 +202,37 @@ void FileCacheSettings::loadFromCollection(const NamedCollection & collection)
     validate();
 }
 
-void FileCacheSettings::validate(bool allow_empty_path)
+void FileCacheSettings::validate()
 {
-    auto settings = *this;
-    if (!allow_empty_path && !settings[FileCacheSetting::path].changed)
+    auto & settings = *this;
+
+    if (!settings[FileCacheSetting::path].changed)
         throw Exception(ErrorCodes::BAD_ARGUMENTS, "`path` is required parameter of cache configuration");
-    if (!settings[FileCacheSetting::max_size].changed)
-        throw Exception(ErrorCodes::BAD_ARGUMENTS, "`max_size` is required parameter of cache configuration");
-    if (settings[FileCacheSetting::max_size] == 0)
+
+    if (!settings[FileCacheSetting::max_size].changed && !settings[FileCacheSetting::max_size_ratio_to_total_space].changed)
+        throw Exception(ErrorCodes::BAD_ARGUMENTS, "Either `max_size` or `max_size_ratio_to_total_space` must be defined in cache configuration");
+
+    if (settings[FileCacheSetting::max_size].changed && settings[FileCacheSetting::max_size_ratio_to_total_space].changed)
+        throw Exception(ErrorCodes::BAD_ARGUMENTS, "`max_size` and `max_size_ratio_to_total_space` cannot be specified at the same time");
+
+    if (settings[FileCacheSetting::max_size].changed && settings[FileCacheSetting::max_size] == 0)
         throw Exception(ErrorCodes::BAD_ARGUMENTS, "`max_size` cannot be 0");
+
+    if (settings[FileCacheSetting::max_size_ratio_to_total_space].changed)
+    {
+        if (settings[FileCacheSetting::max_size_ratio_to_total_space] <= 0 || settings[FileCacheSetting::max_size_ratio_to_total_space] > 1)
+            throw Exception(ErrorCodes::BAD_ARGUMENTS, "`max_size_ratio_to_total_space` must be in range (0, 1]");
+
+        std::filesystem::create_directories(settings[FileCacheSetting::path].value);
+        struct statvfs stat = getStatVFS(settings[FileCacheSetting::path]);
+        const auto total_space = stat.f_blocks * stat.f_frsize;
+        settings[FileCacheSetting::max_size] = static_cast<UInt64>(std::floor(settings[FileCacheSetting::max_size_ratio_to_total_space].value * total_space));
+
+        LOG_TRACE(
+            getLogger("FileCacheSettings"),
+            "Using max_size as ratio {} to total disk space: {} (total space: {})",
+            settings[FileCacheSetting::max_size_ratio_to_total_space].value, settings[FileCacheSetting::max_size].value, total_space);
+    }
 }
 
 }

src/Interpreters/Cache/FileCacheSettings.h

@@ -36,14 +36,18 @@ struct FileCacheSettings
 
     FILE_CACHE_SETTINGS_SUPPORTED_TYPES(FileCacheSettings, DECLARE_SETTING_SUBSCRIPT_OPERATOR)
 
-    void loadFromConfig(const Poco::Util::AbstractConfiguration & config, const std::string & config_prefix, bool allow_empty_path = false);
+    void loadFromConfig(
+        const Poco::Util::AbstractConfiguration & config,
+        const std::string & config_prefix,
+        const std::string & default_cache_path = "");
+
     void loadFromCollection(const NamedCollection & collection);
     void dumpToSystemSettingsColumns(
         MutableColumnsAndConstraints & params,
         const std::string & cache_name,
         const FileCachePtr & cache) const;
 
-    void validate(bool allow_empty_path = false);
+    void validate();
 
 private:
     std::unique_ptr<FileCacheSettingsImpl> impl;

tests/integration/test_filesystem_cache/test.py

@@ -917,3 +917,22 @@ def get_downloaded_elements():
     node.replace_config(
         "/etc/clickhouse-server/config.d/cache_dynamic_resize.xml", default_config
     )
+
+
+def test_max_size_ratio(cluster):
+    node = cluster.instances["node"]
+    node.query(
+        """
+        DROP TABLE IF EXISTS test SYNC;
+        CREATE TABLE test (key UInt32, value String)
+        Engine=MergeTree()
+        ORDER BY value
+        SETTINGS disk = disk(
+            type = cache,
+            name = 'test_max_size_ratio',
+            path = 'test_max_size_ratio/',
+            max_size_ratio_to_total_space=0.7,
+            disk = 'hdd_blob');
+        """
+    )
+    assert node.contains_in_log("Using max_size as ratio 0.7 to total disk space")

tests/queries/0_stateless/02344_describe_cache.reference

@@ -1,2 +1,2 @@
 1
-02344_describe_cache_test	/var/lib/clickhouse/filesystem_caches/02344_describe_cache_test	102400	10000000	33554432	4194304	0	LRU	0.6	5	5000	4194304	16	0	0	0	10	0	0	0	268435456	0	0	1	0	0
+02344_describe_cache_test	/var/lib/clickhouse/filesystem_caches/02344_describe_cache_test	102400	10000000	33554432	4194304	0	LRU	0.6	5	5000	4194304	16	0	0	0	10	0	0	0	268435456	0	0	0	1	0	0