foundationdb/fdbclient/TagThrottle.actor.cpp

113 lines
3.4 KiB
C++

/*
* TagThrottle.actor.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2020 Apple Inc. and the FoundationDB project authors
*
* Licensed 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.
*/
#include "fdbclient/TagThrottle.actor.h"
#include "fdbclient/CommitProxyInterface.h"
#include "fdbclient/DatabaseContext.h"
#include "flow/actorcompiler.h" // has to be last include
void TagSet::addTag(TransactionTagRef tag) {
ASSERT(CLIENT_KNOBS->MAX_TRANSACTION_TAG_LENGTH < 256); // Tag length is encoded with a single byte
ASSERT(CLIENT_KNOBS->MAX_TAGS_PER_TRANSACTION < 256); // Number of tags is encoded with a single byte
if (tag.size() > CLIENT_KNOBS->MAX_TRANSACTION_TAG_LENGTH) {
throw tag_too_long();
}
if (tags.size() >= CLIENT_KNOBS->MAX_TAGS_PER_TRANSACTION) {
throw too_many_tags();
}
TransactionTagRef tagRef(arena, tag);
auto it = find(tags.begin(), tags.end(), tagRef);
if (it == tags.end()) {
tags.push_back(std::move(tagRef));
bytes += tag.size();
}
}
size_t TagSet::size() const {
return tags.size();
}
// Format for throttle key:
//
// tagThrottleKeysPrefix + [auto-throttled (1-byte 0/1)] + [priority (1-byte)] + [tag list]
// tag list consists of 1 or more consecutive tags, each encoded as:
// tag.size() (1 byte) + tag's bytes. For example, tag 'foo' is: \x03foo
// The tags are listed in sorted order
//
// Currently, the throttle API supports only 1 tag per throttle
Key TagThrottleKey::toKey() const {
ASSERT(CLIENT_KNOBS->MAX_TRANSACTION_TAG_LENGTH < 256);
ASSERT(tags.size() > 0);
ASSERT(tags.size() == 1); // SOMEDAY: support multiple tags per throttle
int size = tagThrottleKeysPrefix.size() + tags.size() + 2;
for (auto tag : tags) {
ASSERT(tag.size() <= CLIENT_KNOBS->MAX_TRANSACTION_TAG_LENGTH);
size += tag.size();
}
Key result;
uint8_t* str = new (result.arena()) uint8_t[size];
result.contents() = StringRef(str, size);
memcpy(str, tagThrottleKeysPrefix.begin(), tagThrottleKeysPrefix.size());
str += tagThrottleKeysPrefix.size();
*(str++) = (uint8_t)throttleType;
*(str++) = (uint8_t)priority;
for (auto tag : tags) {
*(str++) = (uint8_t)tag.size();
if (tag.size() > 0) {
memcpy(str, tag.begin(), tag.size());
str += tag.size();
}
}
return result;
}
TagThrottleKey TagThrottleKey::fromKey(const KeyRef& key) {
const uint8_t* str = key.substr(tagThrottleKeysPrefix.size()).begin();
TagThrottleType throttleType = TagThrottleType(*(str++));
TransactionPriority priority = TransactionPriority(*(str++));
TagSet tags;
while (str < key.end()) {
uint8_t size = *(str++);
tags.addTag(TransactionTagRef(str, size));
str += size;
}
return TagThrottleKey(tags, throttleType, priority);
}
TagThrottleValue TagThrottleValue::fromValue(const ValueRef& value) {
TagThrottleValue throttleValue;
BinaryReader reader(value, IncludeVersion(ProtocolVersion::withTagThrottleValueReason()));
reader >> throttleValue;
return throttleValue;
}