projjal commented on a change in pull request #9813:
URL: https://github.com/apache/arrow/pull/9813#discussion_r604831679
##########
File path: cpp/src/gandiva/cache.cc
##########
@@ -38,6 +42,22 @@ int GetCapacity() {
return capacity;
}
+int GetCacheTypeToUse() {
+ int cache_type;
+ const char* env_cache_type = std::getenv("GANDIVA_CACHE_TYPE");
Review comment:
Lets not use environment variable to configure the behaviour, its better
to use some configuration option. The configuration class in Gandiva contains
only a single projector/filter level options. Maybe the first projector/filter
that is built in gandiva can have a config option to set the cache policy,
which cannot be changed afterwards.
##########
File path: cpp/src/gandiva/base_cache.h
##########
@@ -0,0 +1,55 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+
+namespace gandiva {
+
+template <class Key, class Value>
+class BaseCache {
Review comment:
Can you add some comments?
##########
File path: cpp/src/gandiva/lower_value_used_cache.h
##########
@@ -0,0 +1,103 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <set>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+#include "gandiva/base_cache.h"
+
+// modified cache to support evict policy of lower value used.
+namespace gandiva {
+// a cache which evicts the lower value used item when it is full
+template <class Key, class Value>
+class LowerValueUsedCache : public BaseCache<Key, Value> {
+ public:
+ struct hasher {
+ template <typename I>
+ std::size_t operator()(const I& i) const {
+ return i.Hash();
+ }
+ };
+ using map_type = std::unordered_map<
+ Key, std::pair<Value, typename std::set<std::pair<uint64_t,
Key>>::iterator>,
+ hasher>;
+
+ explicit LowerValueUsedCache(size_t capacity) : BaseCache<Key,
Value>(capacity) {}
+
+ LowerValueUsedCache<Key, Value>() : BaseCache<Key, Value>() {}
+
+ size_t size() const override { return map_.size(); }
+
+ size_t capacity() const override { return this->cache_capacity_; }
+
+ bool empty() const override { return map_.empty(); }
+
+ bool contains(const Key& key) override { return map_.find(key) !=
map_.end(); }
+
+ void insert(const Key& key, const Value& value,
+ const uint64_t value_to_order) override {
+ typename map_type::iterator i = map_.find(key);
+ if (i == map_.end()) {
+ // insert item into the cache, but first check if it is full
+ if (size() >= this->cache_capacity_) {
+ // check if the value should be inserted on cache, otherwise just
return
+ if (value_to_order <= lvu_set_.begin()->first) return;
+
+ // cache is full, evict the least recently used item
+ evict();
+ }
+
+ // insert the new item
+ lvu_set_.insert(std::make_pair(value_to_order, key));
+ map_[key] = std::make_pair(value, lvu_set_.begin());
Review comment:
Why adding lvu_set_.begin()
##########
File path: cpp/src/gandiva/cache.h
##########
@@ -31,29 +32,40 @@ int GetCapacity();
GANDIVA_EXPORT
void LogCacheSize(size_t capacity);
+GANDIVA_EXPORT
+int GetCacheTypeToUse();
+
template <class KeyType, typename ValueType>
class Cache {
public:
- explicit Cache(size_t capacity) : cache_(capacity) { LogCacheSize(capacity);
}
+ explicit Cache(size_t capacity, int cache_type_to_use) {
+ if (cache_type_to_use == 0) {
+ this->cache_ = new LowerValueUsedCache<KeyType, ValueType>(capacity);
Review comment:
Why use plain pointers? Its also not being freed. Please use unique_ptr
##########
File path: cpp/src/gandiva/lower_value_used_cache.h
##########
@@ -0,0 +1,103 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <set>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+#include "gandiva/base_cache.h"
+
+// modified cache to support evict policy of lower value used.
+namespace gandiva {
+// a cache which evicts the lower value used item when it is full
+template <class Key, class Value>
+class LowerValueUsedCache : public BaseCache<Key, Value> {
Review comment:
Just evicting based on the build times seems would be problematic since
it might just keep only infrequently used large expressions. You should use a
combination of build time and some aging policy.
Also can you change the name. It sounds confusing.
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