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Polish IterKey and use it in DBImpl::ProcessKeyValueCompaction()

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Summary:
1. Polish IterKey a little bit.
2. Turn to use it in local parameter of current_user_key in DBImpl::ProcessKeyValueCompaction(). Our profile showing that DBImpl::ProcessKeyValueCompaction() has about 14% costs in std::string (the base including reading and writing data but excluding compaction filtering), which is higher than it should be. There are two std::string used in DBImpl::ProcessKeyValueCompaction(), compaction_filter_value and current_user_key and it's hard to distinguish the two.

Test Plan: make all check

Reviewers: haobo, ljin

Reviewed By: haobo

CC: igor, yhchiang, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D17613
This commit is contained in:
sdong 2014-04-08 17:30:45 -07:00
parent dc55903293
commit df2a8b6a1a
2 changed files with 39 additions and 45 deletions
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20
db/db_impl.cc
View file

@ -2523,9 +2523,9 @@ Status DBImpl::ProcessKeyValueCompaction(
Status status;
std::string compaction_filter_value;
ParsedInternalKey ikey;
std::string current_user_key;
IterKey current_user_key;
bool has_current_user_key = false;
std::vector<char> delete_key; // for compaction filter
IterKey delete_key;
SequenceNumber last_sequence_for_key __attribute__((unused)) =
kMaxSequenceNumber;
SequenceNumber visible_in_snapshot = kMaxSequenceNumber;
@ -2589,16 +2589,16 @@ Status DBImpl::ProcessKeyValueCompaction(
// Do not hide error keys
// TODO: error key stays in db forever? Figure out the intention/rationale
// v10 error v8 : we cannot hide v8 even though it's pretty obvious.
current_user_key.clear();
current_user_key.Clear();
has_current_user_key = false;
last_sequence_for_key = kMaxSequenceNumber;
visible_in_snapshot = kMaxSequenceNumber;
} else {
if (!has_current_user_key ||
cfd->user_comparator()->Compare(ikey.user_key,
Slice(current_user_key)) != 0) {
current_user_key.GetKey()) != 0) {
// First occurrence of this user key
current_user_key.assign(ikey.user_key.data(), ikey.user_key.size());
current_user_key.SetUserKey(ikey.user_key);
has_current_user_key = true;
last_sequence_for_key = kMaxSequenceNumber;
visible_in_snapshot = kMaxSequenceNumber;
@ -2617,13 +2617,11 @@ Status DBImpl::ProcessKeyValueCompaction(
compact->compaction->level(), ikey.user_key, value,
&compaction_filter_value, &value_changed);
if (to_delete) {
// make a copy of the original key
delete_key.assign(key.data(), key.data() + key.size());
// convert it to a delete
UpdateInternalKey(&delete_key[0], delete_key.size(),
ikey.sequence, kTypeDeletion);
// make a copy of the original key and convert it to a delete
delete_key.SetInternalKey(ExtractUserKey(key), ikey.sequence,
kTypeDeletion);
// anchor the key again
key = Slice(&delete_key[0], delete_key.size());
key = delete_key.GetKey();
// needed because ikey is backed by key
ParseInternalKey(key, &ikey);
// no value associated with delete

64
db/dbformat.h
View file

@ -242,47 +242,17 @@ class IterKey {
public:
IterKey() : key_(space_), buf_size_(sizeof(space_)), key_size_(0) {}
~IterKey() { Clear(); }
~IterKey() { ResetBuffer(); }
Slice GetKey() const {
if (key_ != nullptr) {
return Slice(key_, key_size_);
} else {
return Slice();
}
}
Slice GetKey() const { return Slice(key_, key_size_); }
bool Valid() const { return key_ != nullptr; }
void Clear() {
if (key_ != nullptr && key_ != space_) {
delete[] key_;
}
key_ = space_;
buf_size_ = sizeof(buf_size_);
}
// Enlarge the buffer size if needed based on key_size.
// By default, static allocated buffer is used. Once there is a key
// larger than the static allocated buffer, another buffer is dynamically
// allocated, until a larger key buffer is requested. In that case, we
// reallocate buffer and delete the old one.
void EnlargeBufferIfNeeded(size_t key_size) {
// If size is smaller than buffer size, continue using current buffer,
// or the static allocated one, as default
if (key_size > buf_size_) {
// Need to enlarge the buffer.
Clear();
key_ = new char[key_size];
buf_size_ = key_size;
}
key_size_ = key_size;
}
void Clear() { key_size_ = 0; }
void SetUserKey(const Slice& user_key) {
size_t size = user_key.size();
EnlargeBufferIfNeeded(size);
memcpy(key_, user_key.data(), size);
key_size_ = size;
}
void SetInternalKey(const Slice& user_key, SequenceNumber s,
@ -291,6 +261,7 @@ class IterKey {
EnlargeBufferIfNeeded(usize + sizeof(uint64_t));
memcpy(key_, user_key.data(), usize);
EncodeFixed64(key_ + usize, PackSequenceAndType(s, value_type));
key_size_ = usize + sizeof(uint64_t);
}
void SetInternalKey(const ParsedInternalKey& parsed_key) {
@ -303,6 +274,31 @@ class IterKey {
size_t key_size_;
char space_[32]; // Avoid allocation for short keys
void ResetBuffer() {
if (key_ != nullptr && key_ != space_) {
delete[] key_;
}
key_ = space_;
buf_size_ = sizeof(buf_size_);
key_size_ = 0;
}
// Enlarge the buffer size if needed based on key_size.
// By default, static allocated buffer is used. Once there is a key
// larger than the static allocated buffer, another buffer is dynamically
// allocated, until a larger key buffer is requested. In that case, we
// reallocate buffer and delete the old one.
void EnlargeBufferIfNeeded(size_t key_size) {
// If size is smaller than buffer size, continue using current buffer,
// or the static allocated one, as default
if (key_size > buf_size_) {
// Need to enlarge the buffer.
ResetBuffer();
key_ = new char[key_size];
buf_size_ = key_size;
}
}
// No copying allowed
IterKey(const IterKey&) = delete;
void operator=(const IterKey&) = delete;