4b15185e25
1. Add hdfs file handle cache for hdfs file reader
Copied from Impala, `https://github.com/apache/impala/blob/master/be/src/util/lru-multi-cache.h`. (Thanks for the Impala team)
This is a lru cache that can store multi entries with same key.
The key is build with {file name + modification time}
The value is the hdfsFile pointer that point to a certain hdfs file.
This cache is to avoid reopen same hdfs file mutli time, which can save
query time.
Add a BE config `max_hdfs_file_handle_cache_num` to limit the max number
of file handle cache, default is 20000.
2. Add file meta cache
The file meta cache is a lru cache. the key is {file name + modification time},
the value is the parsed file meta info of the certain file, which can save
the time of re-parsing file meta everytime.
Currently, it is only used for caching parquet file footer.
The test show that is cache is hit, the `FileOpenTime` and `ParseFooterTime` is reduce to almost 0
in query profile, which can save time when there are lots of files to read.
50 lines
1.5 KiB
C++
50 lines
1.5 KiB
C++
// Licensed to the Apache Software Foundation (ASF) under one
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// or more contributor license agreements. See the NOTICE file
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// distributed with this work for additional information
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// regarding copyright ownership. The ASF licenses this file
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// to you under the Apache License, Version 2.0 (the
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// "License"); you may not use this file except in compliance
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// with the License. You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing,
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// software distributed under the License is distributed on an
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// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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// KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations
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// under the License.
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#include "util/obj_lru_cache.h"
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namespace doris {
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ObjLRUCache::ObjLRUCache(int64_t capacity, uint32_t num_shards) {
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_enabled = (capacity > 0);
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if (_enabled) {
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_cache = std::unique_ptr<Cache>(
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new_lru_cache("ObjLRUCache", capacity, LRUCacheType::NUMBER, num_shards));
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}
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}
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bool ObjLRUCache::lookup(const ObjKey& key, CacheHandle* handle) {
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if (!_enabled) {
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return false;
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}
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auto lru_handle = _cache->lookup(key.key);
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if (!lru_handle) {
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// cache miss
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return false;
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}
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*handle = CacheHandle(_cache.get(), lru_handle);
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return true;
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}
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void ObjLRUCache::erase(const ObjKey& key) {
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if (_enabled) {
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_cache->erase(key.key);
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}
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}
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} // namespace doris
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