/usr/include/ktdbext.h is in libkyototycoon-dev 0.9.56-1.
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* Database extension
* Copyright (C) 2009-2012 FAL Labs
* This file is part of Kyoto Tycoon.
* This program is free software: you can redistribute it and/or modify it under the terms of
* the GNU General Public License as published by the Free Software Foundation, either version
* 3 of the License, or any later version.
* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
* You should have received a copy of the GNU General Public License along with this program.
* If not, see <http://www.gnu.org/licenses/>.
*************************************************************************************************/
#ifndef _KTDBEXT_H // duplication check
#define _KTDBEXT_H
#include <ktcommon.h>
#include <ktutil.h>
#include <ktulog.h>
#include <ktshlib.h>
#include <kttimeddb.h>
namespace kyototycoon { // common namespace
/**
* MapReduce framework.
* @note Although this framework is not distributed or concurrent, it is useful for aggregate
* calculation with less CPU loading and less memory usage.
*/
class MapReduce {
public:
class ValueIterator;
private:
class FlushThread;
class ReduceTaskQueue;
class MapVisitor;
struct MergeLine;
/** An alias of vector of loaded values. */
typedef std::vector<std::string> Values;
/** The default number of temporary databases. */
static const size_t DEFDBNUM = 8;
/** The maxinum number of temporary databases. */
static const size_t MAXDBNUM = 256;
/** The default cache limit. */
static const int64_t DEFCLIM = 512LL << 20;
/** The default cache bucket numer. */
static const int64_t DEFCBNUM = 1048583LL;
/** The bucket number of temprary databases. */
static const int64_t DBBNUM = 512LL << 10;
/** The page size of temprary databases. */
static const int32_t DBPSIZ = 32768;
/** The mapped size of temprary databases. */
static const int64_t DBMSIZ = 516LL * 4096;
/** The page cache capacity of temprary databases. */
static const int64_t DBPCCAP = 16LL << 20;
/** The default number of threads in parallel mode. */
static const size_t DEFTHNUM = 8;
/** The number of slots of the record lock. */
static const int32_t RLOCKSLOT = 256;
public:
/**
* Value iterator for the reducer.
*/
class ValueIterator {
friend class MapReduce;
public:
/**
* Get the next value.
* @param sp the pointer to the variable into which the size of the region of the return
* value is assigned.
* @return the pointer to the next value region, or NULL if no value remains.
*/
const char* next(size_t* sp) {
_assert_(sp);
if (!vptr_) {
if (vit_ == vend_) return NULL;
vptr_ = vit_->data();
vsiz_ = vit_->size();
vit_++;
}
uint64_t vsiz;
size_t step = kc::readvarnum(vptr_, vsiz_, &vsiz);
vptr_ += step;
vsiz_ -= step;
const char* vbuf = vptr_;
*sp = vsiz;
vptr_ += vsiz;
vsiz_ -= vsiz;
if (vsiz_ < 1) vptr_ = NULL;
return vbuf;
}
private:
/**
* Default constructor.
*/
explicit ValueIterator(Values::const_iterator vit, Values::const_iterator vend) :
vit_(vit), vend_(vend), vptr_(NULL), vsiz_(0) {
_assert_(true);
}
/**
* Destructor.
*/
~ValueIterator() {
_assert_(true);
}
/** Dummy constructor to forbid the use. */
ValueIterator(const ValueIterator&);
/** Dummy Operator to forbid the use. */
ValueIterator& operator =(const ValueIterator&);
/** The current iterator of loaded values. */
Values::const_iterator vit_;
/** The ending iterator of loaded values. */
Values::const_iterator vend_;
/** The pointer of the current value. */
const char* vptr_;
/** The size of the current value. */
size_t vsiz_;
};
/**
* Execution options.
*/
enum Option {
XNOLOCK = 1 << 0, ///< avoid locking against update operations
XPARAMAP = 1 << 1, ///< run mappers in parallel
XPARARED = 1 << 2, ///< run reducers in parallel
XPARAFLS = 1 << 3, ///< run cache flushers in parallel
XNOCOMP = 1 << 8 ///< avoid compression of temporary databases
};
/**
* Default constructor.
*/
explicit MapReduce() :
rcomp_(NULL), tmpdbs_(NULL), dbnum_(DEFDBNUM), dbclock_(0),
mapthnum_(DEFTHNUM), redthnum_(DEFTHNUM), flsthnum_(DEFTHNUM),
cache_(NULL), csiz_(0), clim_(DEFCLIM), cbnum_(DEFCBNUM), flsths_(NULL),
redtasks_(NULL), redaborted_(false), rlocks_(NULL) {
_assert_(true);
}
/**
* Destructor.
*/
virtual ~MapReduce() {
_assert_(true);
}
/**
* Map a record data.
* @param kbuf the pointer to the key region.
* @param ksiz the size of the key region.
* @param vbuf the pointer to the value region.
* @param vsiz the size of the value region.
* @return true on success, or false on failure.
* @note This function can call the MapReduce::emit method to emit a record. To avoid
* deadlock, any explicit database operation must not be performed in this function.
*/
virtual bool map(const char* kbuf, size_t ksiz, const char* vbuf, size_t vsiz) = 0;
/**
* Reduce a record data.
* @param kbuf the pointer to the key region.
* @param ksiz the size of the key region.
* @param iter the iterator to get the values.
* @return true on success, or false on failure.
* @note To avoid deadlock, any explicit database operation must not be performed in this
* function.
*/
virtual bool reduce(const char* kbuf, size_t ksiz, ValueIterator* iter) = 0;
/**
* Preprocess the map operations.
* @return true on success, or false on failure.
* @note This function can call the MapReduce::emit method to emit a record. To avoid
* deadlock, any explicit database operation must not be performed in this function.
*/
virtual bool preprocess() {
_assert_(true);
return true;
}
/**
* Mediate between the map and the reduce phases.
* @return true on success, or false on failure.
* @note This function can call the MapReduce::emit method to emit a record. To avoid
* deadlock, any explicit database operation must not be performed in this function.
*/
virtual bool midprocess() {
_assert_(true);
return true;
}
/**
* Postprocess the reduce operations.
* @return true on success, or false on failure.
* @note To avoid deadlock, any explicit database operation must not be performed in this
* function.
*/
virtual bool postprocess() {
_assert_(true);
return true;
}
/**
* Process a log message.
* @param name the name of the event.
* @param message a supplement message.
* @return true on success, or false on failure.
*/
virtual bool log(const char* name, const char* message) {
_assert_(name && message);
return true;
}
/**
* Execute the MapReduce process about a database.
* @param db the source database.
* @param tmppath the path of a directory for the temporary data storage. If it is an empty
* string, temporary data are handled on memory.
* @param opts the optional features by bitwise-or: MapReduce::XNOLOCK to avoid locking
* against update operations by other threads, MapReduce::XNOCOMP to avoid compression of
* temporary databases.
* @return true on success, or false on failure.
*/
bool execute(TimedDB* db, const std::string& tmppath = "", uint32_t opts = 0) {
int64_t count = db->count();
if (count < 0) {
if (db->error() != kc::BasicDB::Error::NOIMPL) return false;
count = 0;
}
bool err = false;
double stime, etime;
db_ = db;
rcomp_ = kc::LEXICALCOMP;
kc::BasicDB* idb = db->reveal_inner_db();
const std::type_info& info = typeid(*idb);
if (info == typeid(kc::GrassDB)) {
kc::GrassDB* gdb = (kc::GrassDB*)idb;
rcomp_ = gdb->rcomp();
} else if (info == typeid(kc::TreeDB)) {
kc::TreeDB* tdb = (kc::TreeDB*)idb;
rcomp_ = tdb->rcomp();
} else if (info == typeid(kc::ForestDB)) {
kc::ForestDB* fdb = (kc::ForestDB*)idb;
rcomp_ = fdb->rcomp();
}
tmpdbs_ = new kc::BasicDB*[dbnum_];
if (tmppath.empty()) {
if (!logf("prepare", "started to open temporary databases on memory")) err = true;
stime = kc::time();
for (size_t i = 0; i < dbnum_; i++) {
kc::GrassDB* gdb = new kc::GrassDB;
int32_t myopts = 0;
if (!(opts & XNOCOMP)) myopts |= kc::GrassDB::TCOMPRESS;
gdb->tune_options(myopts);
gdb->tune_buckets(DBBNUM / 2);
gdb->tune_page(DBPSIZ);
gdb->tune_page_cache(DBPCCAP);
gdb->tune_comparator(rcomp_);
gdb->open("%", kc::GrassDB::OWRITER | kc::GrassDB::OCREATE | kc::GrassDB::OTRUNCATE);
tmpdbs_[i] = gdb;
}
etime = kc::time();
if (!logf("prepare", "opening temporary databases finished: time=%.6f", etime - stime))
err = true;
if (err) {
delete[] tmpdbs_;
return false;
}
} else {
kc::File::Status sbuf;
if (!kc::File::status(tmppath, &sbuf) || !sbuf.isdir) {
db->set_error(kc::BasicDB::Error::NOREPOS, "no such directory");
delete[] tmpdbs_;
return false;
}
if (!logf("prepare", "started to open temporary databases under %s", tmppath.c_str()))
err = true;
stime = kc::time();
uint32_t pid = getpid() & kc::UINT16MAX;
uint32_t tid = kc::Thread::hash() & kc::UINT16MAX;
uint32_t ts = kc::time() * 1000;
for (size_t i = 0; i < dbnum_; i++) {
std::string childpath =
kc::strprintf("%s%cmr-%04x-%04x-%08x-%03d%ckct", tmppath.c_str(),
kc::File::PATHCHR, pid, tid, ts, (int)(i + 1), kc::File::EXTCHR);
kc::TreeDB* tdb = new kc::TreeDB;
int32_t myopts = kc::TreeDB::TSMALL | kc::TreeDB::TLINEAR;
if (!(opts & XNOCOMP)) myopts |= kc::TreeDB::TCOMPRESS;
tdb->tune_options(myopts);
tdb->tune_buckets(DBBNUM);
tdb->tune_page(DBPSIZ);
tdb->tune_map(DBMSIZ);
tdb->tune_page_cache(DBPCCAP);
tdb->tune_comparator(rcomp_);
if (!tdb->open(childpath,
kc::TreeDB::OWRITER | kc::TreeDB::OCREATE | kc::TreeDB::OTRUNCATE)) {
const kc::BasicDB::Error& e = tdb->error();
db->set_error(e.code(), e.message());
err = true;
}
tmpdbs_[i] = tdb;
}
etime = kc::time();
if (!logf("prepare", "opening temporary databases finished: time=%.6f", etime - stime))
err = true;
if (err) {
for (size_t i = 0; i < dbnum_; i++) {
delete tmpdbs_[i];
}
delete[] tmpdbs_;
return false;
}
}
if (opts & XPARARED) redtasks_ = new ReduceTaskQueue;
if (opts & XPARAFLS) flsths_ = new std::deque<FlushThread*>;
if (opts & XNOLOCK) {
MapChecker mapchecker;
MapVisitor mapvisitor(this, &mapchecker, count);
mapvisitor.visit_before();
if (!err) {
TimedDB::Cursor* cur = db->cursor();
if (!cur->jump() && cur->error() != kc::BasicDB::Error::NOREC) err = true;
while (!err) {
if (!cur->accept(&mapvisitor, false, true)) {
if (cur->error() != kc::BasicDB::Error::NOREC) err = true;
break;
}
}
delete cur;
}
if (mapvisitor.error()) err = true;
mapvisitor.visit_after();
} else if (opts & XPARAMAP) {
MapChecker mapchecker;
MapVisitor mapvisitor(this, &mapchecker, count);
rlocks_ = new kc::SlottedMutex(RLOCKSLOT);
if (!err && !db->scan_parallel(&mapvisitor, mapthnum_, &mapchecker)) {
db_->set_error(kc::BasicDB::Error::LOGIC, "mapper failed");
err = true;
}
delete rlocks_;
rlocks_ = NULL;
if (mapvisitor.error()) err = true;
} else {
MapChecker mapchecker;
MapVisitor mapvisitor(this, &mapchecker, count);
if (!err && !db->iterate(&mapvisitor, false, &mapchecker)) err = true;
if (mapvisitor.error()) err = true;
}
if (flsths_) {
delete flsths_;
flsths_ = NULL;
}
if (redtasks_) {
delete redtasks_;
redtasks_ = NULL;
}
if (!logf("clean", "closing the temporary databases")) err = true;
stime = kc::time();
for (size_t i = 0; i < dbnum_; i++) {
std::string path = tmpdbs_[i]->path();
if (!tmpdbs_[i]->clear()) {
const kc::BasicDB::Error& e = tmpdbs_[i]->error();
db->set_error(e.code(), e.message());
err = true;
}
if (!tmpdbs_[i]->close()) {
const kc::BasicDB::Error& e = tmpdbs_[i]->error();
db->set_error(e.code(), e.message());
err = true;
}
if (!tmppath.empty()) kc::File::remove(path);
delete tmpdbs_[i];
}
etime = kc::time();
if (!logf("clean", "closing the temporary databases finished: time=%.6f",
etime - stime)) err = true;
delete[] tmpdbs_;
return !err;
}
/**
* Set the storage configurations.
* @param dbnum the number of temporary databases.
* @param clim the limit size of the internal cache.
* @param cbnum the bucket number of the internal cache.
*/
void tune_storage(int32_t dbnum, int64_t clim, int64_t cbnum) {
_assert_(true);
dbnum_ = dbnum > 0 ? dbnum : DEFDBNUM;
if (dbnum_ > MAXDBNUM) dbnum_ = MAXDBNUM;
clim_ = clim > 0 ? clim : DEFCLIM;
cbnum_ = cbnum > 0 ? cbnum : DEFCBNUM;
if (cbnum_ > kc::INT16MAX) cbnum_ = kc::nearbyprime(cbnum_);
}
/**
* Set the thread configurations.
* @param mapthnum the number of threads for the mapper.
* @param redthnum the number of threads for the reducer.
* @param flsthnum the number of threads for the internal flusher.
*/
void tune_thread(int32_t mapthnum, int32_t redthnum, int32_t flsthnum) {
_assert_(true);
mapthnum_ = mapthnum > 0 ? mapthnum : DEFTHNUM;
redthnum_ = redthnum > 0 ? redthnum : DEFTHNUM;
flsthnum_ = flsthnum > 0 ? flsthnum : DEFTHNUM;
}
protected:
/**
* Emit a record from the mapper.
* @param kbuf the pointer to the key region.
* @param ksiz the size of the key region.
* @param vbuf the pointer to the value region.
* @param vsiz the size of the value region.
* @return true on success, or false on failure.
*/
bool emit(const char* kbuf, size_t ksiz, const char* vbuf, size_t vsiz) {
_assert_(kbuf && ksiz <= kc::MEMMAXSIZ && vbuf && vsiz <= kc::MEMMAXSIZ);
bool err = false;
size_t rsiz = kc::sizevarnum(vsiz) + vsiz;
char stack[kc::NUMBUFSIZ*4];
char* rbuf = rsiz > sizeof(stack) ? new char[rsiz] : stack;
char* wp = rbuf;
wp += kc::writevarnum(rbuf, vsiz);
std::memcpy(wp, vbuf, vsiz);
if (rlocks_) {
size_t bidx = kc::TinyHashMap::hash_record(kbuf, ksiz) % cbnum_;
size_t lidx = bidx % RLOCKSLOT;
rlocks_->lock(lidx);
cache_->append(kbuf, ksiz, rbuf, rsiz);
rlocks_->unlock(lidx);
} else {
cache_->append(kbuf, ksiz, rbuf, rsiz);
}
if (rbuf != stack) delete[] rbuf;
csiz_ += kc::sizevarnum(ksiz) + ksiz + rsiz;
return !err;
}
private:
/**
* Cache flusher.
*/
class FlushThread : public kc::Thread {
public:
/** constructor */
explicit FlushThread(MapReduce* mr, kc::BasicDB* tmpdb,
kc::TinyHashMap* cache, size_t csiz, bool cown) :
mr_(mr), tmpdb_(tmpdb), cache_(cache), csiz_(csiz), cown_(cown), err_(false) {}
/** perform the concrete process */
void run() {
if (!mr_->logf("map", "started to flushing the cache: count=%lld size=%lld",
(long long)cache_->count(), (long long)csiz_)) err_ = true;
double stime = kc::time();
kc::BasicDB* tmpdb = tmpdb_;
kc::TinyHashMap* cache = cache_;
bool cown = cown_;
kc::TinyHashMap::Sorter sorter(cache);
const char* kbuf, *vbuf;
size_t ksiz, vsiz;
while ((kbuf = sorter.get(&ksiz, &vbuf, &vsiz)) != NULL) {
if (!tmpdb->append(kbuf, ksiz, vbuf, vsiz)) {
const kc::BasicDB::Error& e = tmpdb->error();
mr_->db_->set_error(e.code(), e.message());
err_ = true;
}
sorter.step();
if (cown) cache->remove(kbuf, ksiz);
}
double etime = kc::time();
if (!mr_->logf("map", "flushing the cache finished: time=%.6f", etime - stime))
err_ = true;
if (cown) delete cache;
}
/** check the error flag. */
bool error() {
return err_;
}
private:
MapReduce* mr_; ///< driver
kc::BasicDB* tmpdb_; ///< temprary database
kc::TinyHashMap* cache_; ///< cache for emitter
size_t csiz_; ///< current cache size
bool cown_; ///< cache ownership flag
bool err_; ///< error flag
};
/**
* Task queue for parallel reducer.
*/
class ReduceTaskQueue : public kc::TaskQueue {
public:
/**
* Task for parallel reducer.
*/
class ReduceTask : public Task {
friend class ReduceTaskQueue;
public:
/** constructor */
explicit ReduceTask(MapReduce* mr, const char* kbuf, size_t ksiz, const Values& values) :
mr_(mr), key_(kbuf, ksiz), values_(values) {}
private:
MapReduce* mr_; ///< driver
std::string key_; ///< key
Values values_; ///< values
};
/** constructor */
explicit ReduceTaskQueue() {}
private:
/** process a task */
void do_task(Task* task) {
ReduceTask* rtask = (ReduceTask*)task;
ValueIterator iter(rtask->values_.begin(), rtask->values_.end());
if (!rtask->mr_->reduce(rtask->key_.data(), rtask->key_.size(), &iter))
rtask->mr_->redaborted_ = true;
delete rtask;
}
};
/**
* Checker for the map process.
*/
class MapChecker : public kc::BasicDB::ProgressChecker {
public:
/** constructor */
explicit MapChecker() : stop_(false) {}
/** stop the process */
void stop() {
stop_ = true;
}
/** check whether stopped */
bool stopped() {
return stop_;
}
private:
/** check whether stopped */
bool check(const char* name, const char* message, int64_t curcnt, int64_t allcnt) {
return !stop_;
}
bool stop_; ///< flag for stop
};
/**
* Visitor for the map process.
*/
class MapVisitor : public TimedDB::Visitor {
public:
/** constructor */
explicit MapVisitor(MapReduce* mr, MapChecker* checker, int64_t scale) :
mr_(mr), checker_(checker), scale_(scale), stime_(0), err_(false) {}
/** get the error flag */
bool error() {
return err_;
}
/** preprocess the mappter */
void visit_before() {
mr_->dbclock_ = 0;
mr_->cache_ = new kc::TinyHashMap(mr_->cbnum_);
mr_->csiz_ = 0;
if (!mr_->preprocess()) err_ = true;
if (mr_->cache_->count() > 0 && !mr_->flush_cache()) err_ = true;
if (!mr_->logf("map", "started the map process: scale=%lld", (long long)scale_))
err_ = true;
stime_ = kc::time();
}
/** postprocess the mappter and call the reducer */
void visit_after() {
if (mr_->cache_->count() > 0 && !mr_->flush_cache()) err_ = true;
double etime = kc::time();
if (!mr_->logf("map", "the map process finished: time=%.6f", etime - stime_))
err_ = true;
if (!mr_->midprocess()) err_ = true;
if (mr_->cache_->count() > 0 && !mr_->flush_cache()) err_ = true;
delete mr_->cache_;
if (mr_->flsths_ && !mr_->flsths_->empty()) {
std::deque<FlushThread*>::iterator flthit = mr_->flsths_->begin();
std::deque<FlushThread*>::iterator flthitend = mr_->flsths_->end();
while (flthit != flthitend) {
FlushThread* flth = *flthit;
flth->join();
if (flth->error()) err_ = true;
delete flth;
++flthit;
}
}
if (!err_ && !mr_->execute_reduce()) err_ = true;
if (!mr_->postprocess()) err_ = true;
}
private:
/** visit a record */
const char* visit_full(const char* kbuf, size_t ksiz,
const char* vbuf, size_t vsiz, size_t* sp, int64_t* xtp) {
if (!mr_->map(kbuf, ksiz, vbuf, vsiz)) {
checker_->stop();
err_ = true;
}
if (mr_->rlocks_) {
if (mr_->csiz_ >= mr_->clim_) {
mr_->rlocks_->lock_all();
if (mr_->csiz_ >= mr_->clim_ && !mr_->flush_cache()) {
checker_->stop();
err_ = true;
}
mr_->rlocks_->unlock_all();
}
} else {
if (mr_->csiz_ >= mr_->clim_ && !mr_->flush_cache()) {
checker_->stop();
err_ = true;
}
}
return NOP;
}
MapReduce* mr_; ///< driver
MapChecker* checker_; ///< checker
int64_t scale_; ///< number of records
double stime_; ///< start time
bool err_; ///< error flag
};
/**
* Front line of a merging list.
*/
struct MergeLine {
kc::BasicDB::Cursor* cur; ///< cursor
kc::Comparator* rcomp; ///< record comparator
char* kbuf; ///< pointer to the key
size_t ksiz; ///< size of the key
const char* vbuf; ///< pointer to the value
size_t vsiz; ///< size of the value
/** comparing operator */
bool operator <(const MergeLine& right) const {
return rcomp->compare(kbuf, ksiz, right.kbuf, right.ksiz) > 0;
}
};
/**
* Process a log message.
* @param name the name of the event.
* @param format the printf-like format string.
* @param ... used according to the format string.
* @return true on success, or false on failure.
*/
bool logf(const char* name, const char* format, ...) {
_assert_(name && format);
va_list ap;
va_start(ap, format);
std::string message;
kc::vstrprintf(&message, format, ap);
va_end(ap);
return log(name, message.c_str());
}
/**
* Flush all cache records.
* @return true on success, or false on failure.
*/
bool flush_cache() {
_assert_(true);
bool err = false;
kc::BasicDB* tmpdb = tmpdbs_[dbclock_];
dbclock_ = (dbclock_ + 1) % dbnum_;
if (flsths_) {
size_t num = flsths_->size();
if (num >= flsthnum_ || num >= dbnum_) {
FlushThread* flth = flsths_->front();
flsths_->pop_front();
flth->join();
if (flth->error()) err = true;
delete flth;
}
FlushThread* flth = new FlushThread(this, tmpdb, cache_, csiz_, true);
cache_ = new kc::TinyHashMap(cbnum_);
csiz_ = 0;
flth->start();
flsths_->push_back(flth);
} else {
FlushThread flth(this, tmpdb, cache_, csiz_, false);
flth.run();
if (flth.error()) err = true;
cache_->clear();
csiz_ = 0;
}
return !err;
}
/**
* Execute the reduce part.
* @return true on success, or false on failure.
*/
bool execute_reduce() {
bool err = false;
int64_t scale = 0;
for (size_t i = 0; i < dbnum_; i++) {
scale += tmpdbs_[i]->count();
}
if (!logf("reduce", "started the reduce process: scale=%lld", (long long)scale)) err = true;
double stime = kc::time();
if (redtasks_) redtasks_->start(redthnum_);
std::priority_queue<MergeLine> lines;
for (size_t i = 0; i < dbnum_; i++) {
MergeLine line;
line.cur = tmpdbs_[i]->cursor();
line.rcomp = rcomp_;
line.cur->jump();
line.kbuf = line.cur->get(&line.ksiz, &line.vbuf, &line.vsiz, true);
if (line.kbuf) {
lines.push(line);
} else {
delete line.cur;
}
}
char* lkbuf = NULL;
size_t lksiz = 0;
Values values;
while (!err && !lines.empty()) {
MergeLine line = lines.top();
lines.pop();
if (lkbuf && (lksiz != line.ksiz || std::memcmp(lkbuf, line.kbuf, lksiz))) {
if (!call_reducer(lkbuf, lksiz, values)) err = true;
values.clear();
}
values.push_back(std::string(line.vbuf, line.vsiz));
delete[] lkbuf;
lkbuf = line.kbuf;
lksiz = line.ksiz;
line.kbuf = line.cur->get(&line.ksiz, &line.vbuf, &line.vsiz, true);
if (line.kbuf) {
lines.push(line);
} else {
delete line.cur;
}
}
if (lkbuf) {
if (!err && !call_reducer(lkbuf, lksiz, values)) err = true;
values.clear();
delete[] lkbuf;
}
while (!lines.empty()) {
MergeLine line = lines.top();
lines.pop();
delete[] line.kbuf;
delete line.cur;
}
if (redtasks_) redtasks_->finish();
double etime = kc::time();
if (!logf("reduce", "the reduce process finished: time=%.6f", etime - stime)) err = true;
return !err;
}
/**
* Call the reducer.
* @param kbuf the pointer to the key region.
* @param ksiz the size of the key region.
* @param values a vector of the values.
* @return true on success, or false on failure.
*/
bool call_reducer(const char* kbuf, size_t ksiz, const Values& values) {
_assert_(kbuf && ksiz <= kc::MEMMAXSIZ);
if (redtasks_) {
if (redaborted_) return false;
ReduceTaskQueue::ReduceTask* task =
new ReduceTaskQueue::ReduceTask(this, kbuf, ksiz, values);
redtasks_->add_task(task);
return true;
}
bool err = false;
ValueIterator iter(values.begin(), values.end());
if (!reduce(kbuf, ksiz, &iter)) err = true;
return !err;
}
/** Dummy constructor to forbid the use. */
MapReduce(const MapReduce&);
/** Dummy Operator to forbid the use. */
MapReduce& operator =(const MapReduce&);
/** The internal database. */
TimedDB* db_;
/** The record comparator. */
kc::Comparator* rcomp_;
/** The temporary databases. */
kc::BasicDB** tmpdbs_;
/** The number of temporary databases. */
size_t dbnum_;
/** The logical clock for temporary databases. */
int64_t dbclock_;
/** The number of the mapper threads. */
size_t mapthnum_;
/** The number of the reducer threads. */
size_t redthnum_;
/** The number of the flusher threads. */
size_t flsthnum_;
/** The cache for emitter. */
kc::TinyHashMap* cache_;
/** The current size of the cache for emitter. */
int64_t csiz_;
/** The limit size of the cache for emitter. */
int64_t clim_;
/** The bucket number of the cache for emitter. */
int64_t cbnum_;
/** The flush threads. */
std::deque<FlushThread*>* flsths_;
/** The task queue for parallel reducer. */
kc::TaskQueue* redtasks_;
/** The flag whether aborted. */
bool redaborted_;
/** The whole lock. */
kc::SlottedMutex* rlocks_;
};
} // common namespace
#endif // duplication check
// END OF FILE
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