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/*
* memTreeComponent.h
*
* Copyright 2009-2012 Yahoo! Inc.
*
* 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.
*
*/
#ifndef _MEMTREECOMPONENT_H_
#define _MEMTREECOMPONENT_H_
#include <set>
#include <assert.h>
#include <mergeStats.h>
#include <stasis/util/stlslab.h>
class memTreeComponent {
public:
// typedef std::set<datatuple*, datatuple, stlslab<datatuple*> > rbtree_t;
typedef std::set<dataTuple*, dataTuple> rbtree_t;
typedef rbtree_t* rbtree_ptr_t;
static void tearDownTree(rbtree_ptr_t t);
///////////////////////////////////////////////////////////////
// Plain iterator; cannot cope with changes to underlying tree
///////////////////////////////////////////////////////////////
class iterator
{
private:
typedef rbtree_t::const_iterator MTITER;
public:
iterator( rbtree_t *s )
: first_(true),
done_(s == NULL) {
init_iterators(s, NULL, NULL);
}
iterator( rbtree_t *s, dataTuple *&key )
: first_(true), done_(s == NULL) {
init_iterators(s, key, NULL);
}
~iterator() {
delete it_;
delete itend_;
}
dataTuple* next_callerFrees() {
if(done_) { return NULL; }
if(first_) { first_ = 0;} else { (*it_)++; }
if(*it_==*itend_) { done_= true; return NULL; }
return (*(*it_))->create_copy();
}
private:
void init_iterators(rbtree_t * s, dataTuple * key1, dataTuple * key2) {
if(s) {
it_ = key1 ? new MTITER(s->lower_bound(key1)) : new MTITER(s->begin());
itend_ = key2 ? new MTITER(s->upper_bound(key2)) : new MTITER(s->end());
if(*it_ == *itend_) { done_ = true; }
if(key1) {
if(done_) {
// DEBUG("memtree opened at eot\n");
} else {
// DEBUG("memtree opened key = %s\n", (**it_)->key());
}
}
} else {
it_ = NULL;
itend_ = NULL;
}
}
explicit iterator() { abort(); }
void operator=(iterator & t) { abort(); }
int operator-(iterator & t) { abort(); }
private:
bool first_;
bool done_;
MTITER *it_;
MTITER *itend_;
};
///////////////////////////////////////////////////////////////
// Revalidating iterator; automatically copes with changes to underlying tree
///////////////////////////////////////////////////////////////
class revalidatingIterator
{
private:
typedef rbtree_t::const_iterator MTITER;
public:
revalidatingIterator( rbtree_t *s, pthread_mutex_t * rb_mut ) : s_(s), mut_(rb_mut) {
if(mut_) pthread_mutex_lock(mut_);
if(s_->begin() == s_->end()) {
next_ret_ = NULL;
} else {
next_ret_ = (*s_->begin())->create_copy(); // the create_copy() calls have to happen before we release mut_...
}
if(mut_) pthread_mutex_unlock(mut_);
}
revalidatingIterator( rbtree_t *s, pthread_mutex_t * rb_mut, dataTuple *&key ) : s_(s), mut_(rb_mut) {
if(mut_) pthread_mutex_lock(mut_);
if(key) {
if(s_->find(key) != s_->end()) {
next_ret_ = (*(s_->find(key)))->create_copy();
} else if(s_->upper_bound(key) != s_->end()) {
next_ret_ = (*(s_->upper_bound(key)))->create_copy();
} else {
next_ret_ = NULL;
}
} else {
if(s_->begin() == s_->end()) {
next_ret_ = NULL;
} else {
next_ret_ = (*s_->begin())->create_copy(); // the create_copy() calls have to happen before we release mut_...
}
}
// DEBUG("changing mem next ret = %s key = %s\n", next_ret_ ? (const char*)next_ret_->key() : "NONE", key ? (const char*)key->key() : "NULL");
if(mut_) pthread_mutex_unlock(mut_);
}
~revalidatingIterator() {
if(next_ret_) dataTuple::freetuple(next_ret_);
}
dataTuple* next_callerFrees() {
if(mut_) pthread_mutex_lock(mut_);
dataTuple * ret = next_ret_;
if(next_ret_) {
if(s_->upper_bound(next_ret_) == s_->end()) {
next_ret_ = 0;
} else {
next_ret_ = (*s_->upper_bound(next_ret_))->create_copy();
}
}
if(mut_) pthread_mutex_unlock(mut_);
return ret;
}
private:
explicit revalidatingIterator() { abort(); }
void operator=(revalidatingIterator & t) { abort(); }
int operator-(revalidatingIterator & t) { abort(); }
rbtree_t *s_;
dataTuple * next_ret_;
pthread_mutex_t * mut_;
};
///////////////////////////////////////////////////////////////
// Revalidating iterator; automatically copes with changes to underlying tree
///////////////////////////////////////////////////////////////
class batchedRevalidatingIterator
{
private:
typedef rbtree_t::const_iterator MTITER;
void populate_next_ret_impl(std::_Rb_tree_const_iterator<dataTuple*>/*MTITER*/ it) {
num_batched_ = 0;
cur_off_ = 0;
while(it != s_->end() && num_batched_ < batch_size_) {
next_ret_[num_batched_] = (*it)->create_copy();
num_batched_++;
it++;
}
}
void populate_next_ret(dataTuple *key=NULL, bool include_key=false) {
if(cur_off_ == num_batched_) {
if(mut_) pthread_mutex_lock(mut_);
if(mgr_) {
while(mgr_->get_merge_stats(0)->get_current_size() < (0.8 * (double)target_size_) && ! *flushing_) { // TODO: how to pick this threshold? Too high, and the disk is idle. Too low, and we waste ram.
pthread_mutex_unlock(mut_);
struct timespec ts;
mergeManager::double_to_ts(&ts, 0.1);
nanosleep(&ts, 0);
pthread_mutex_lock(mut_);
}
}
if(key) {
populate_next_ret_impl(include_key ? s_->lower_bound(key) : s_->upper_bound(key));
} else {
populate_next_ret_impl(s_->begin());
}
if(mut_) pthread_mutex_unlock(mut_);
}
}
public:
batchedRevalidatingIterator( rbtree_t *s, mergeManager * mgr, int64_t target_size, bool * flushing, int batch_size, pthread_mutex_t * rb_mut ) : s_(s), mgr_(mgr), target_size_(target_size), flushing_(flushing), batch_size_(batch_size), num_batched_(batch_size), cur_off_(batch_size), mut_(rb_mut) {
next_ret_ = (dataTuple**)malloc(sizeof(next_ret_[0]) * batch_size_);
populate_next_ret();
}
batchedRevalidatingIterator( rbtree_t *s, int batch_size, pthread_mutex_t * rb_mut, dataTuple *&key ) : s_(s), mgr_(NULL), target_size_(0), flushing_(0), batch_size_(batch_size), num_batched_(batch_size), cur_off_(batch_size), mut_(rb_mut) {
next_ret_ = (dataTuple**)malloc(sizeof(next_ret_[0]) * batch_size_);
populate_next_ret(key, true);
}
~batchedRevalidatingIterator() {
for(int i = cur_off_; i < num_batched_; i++) {
dataTuple::freetuple(next_ret_[i]);
}
free(next_ret_);
}
dataTuple* next_callerFrees() {
if(cur_off_ == num_batched_) { return NULL; } // the last thing we did is call populate_next_ret_(), which only leaves us in this state at the end of the iterator.
dataTuple * ret = next_ret_[cur_off_];
cur_off_++;
populate_next_ret(ret);
return ret;
}
private:
explicit batchedRevalidatingIterator() { abort(); }
void operator=(batchedRevalidatingIterator & t) { abort(); }
int operator-(batchedRevalidatingIterator & t) { abort(); }
rbtree_t *s_;
dataTuple ** next_ret_;
mergeManager * mgr_;
int64_t target_size_; // the low-water size for the tree. If cur_size_ is not null, and *cur_size_ < C * target_size_, we sleep.
bool* flushing_; // never block if *flushing is true.
int batch_size_;
int num_batched_;
int cur_off_;
pthread_mutex_t * mut_;
};
};
#endif //_MEMTREECOMPONENT_H_
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