/
bgfetcher.cc
160 lines (140 loc) · 5.38 KB
/
bgfetcher.cc
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/* -*- Mode: C++; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
#include "config.h"
#include "ep.hh"
#include "iomanager/iomanager.h"
#include "kvshard.hh"
const double BgFetcher::sleepInterval = 1.0;
void BgFetcher::start() {
LockHolder lh(taskMutex);
pendingFetch.cas(false, true);
IOManager* iom = IOManager::get();
iom->scheduleMultiBGFetcher(&(store->getEPEngine()), this,
Priority::BgFetcherPriority,
shard->getId());
assert(taskId > 0);
}
void BgFetcher::stop() {
LockHolder lh(taskMutex);
pendingFetch.cas(true, false);
assert(taskId > 0);
IOManager::get()->cancel(taskId);
}
void BgFetcher::notifyBGEvent(void) {
++stats.numRemainingBgJobs;
if (pendingFetch.cas(false, true)) {
LockHolder lh(taskMutex);
assert(taskId > 0);
IOManager::get()->wake(taskId);
}
}
void BgFetcher::doFetch(uint16_t vbId) {
hrtime_t startTime(gethrtime());
LOG(EXTENSION_LOG_DEBUG, "BgFetcher is fetching data, vBucket = %d "
"numDocs = %d, startTime = %lld\n", vbId, items2fetch.size(),
startTime/1000000);
shard->getROUnderlying()->getMulti(vbId, items2fetch);
int totalfetches = 0;
std::vector<VBucketBGFetchItem *> fetchedItems;
vb_bgfetch_queue_t::iterator itr = items2fetch.begin();
for (; itr != items2fetch.end(); itr++) {
std::list<VBucketBGFetchItem *> &requestedItems = (*itr).second;
std::list<VBucketBGFetchItem *>::iterator itm = requestedItems.begin();
for(; itm != requestedItems.end(); itm++) {
if ((*itm)->value.getStatus() != ENGINE_SUCCESS &&
(*itm)->canRetry()) {
// underlying kvstore failed to fetch requested data
// don't return the failed request yet. Will requeue
// it for retry later
LOG(EXTENSION_LOG_WARNING, "Warning: bgfetcher failed to fetch "
"data for vb = %d seq = %lld key = %s retry = %d\n", vbId,
(*itr).first, (*itm)->key.c_str(), (*itm)->getRetryCount());
continue;
}
fetchedItems.push_back(*itm);
++totalfetches;
}
}
if (totalfetches > 0) {
store->completeBGFetchMulti(vbId, fetchedItems, startTime);
stats.getMultiHisto.add((gethrtime()-startTime)/1000, totalfetches);
}
// failed requests will get requeued for retry within clearItems()
clearItems(vbId);
}
void BgFetcher::clearItems(uint16_t vbId) {
vb_bgfetch_queue_t::iterator itr = items2fetch.begin();
size_t numRequeuedItems = 0;
for(; itr != items2fetch.end(); itr++) {
// every fetched item belonging to the same seq_id shares
// a single data buffer, just delete it from the first fetched item
std::list<VBucketBGFetchItem *> &doneItems = (*itr).second;
VBucketBGFetchItem *firstItem = doneItems.front();
firstItem->delValue();
std::list<VBucketBGFetchItem *>::iterator dItr = doneItems.begin();
for (; dItr != doneItems.end(); dItr++) {
if ((*dItr)->value.getStatus() == ENGINE_SUCCESS ||
!(*dItr)->canRetry()) {
delete *dItr;
} else {
RCPtr<VBucket> vb = store->getVBuckets().getBucket(vbId);
assert(vb);
(*dItr)->incrRetryCount();
LOG(EXTENSION_LOG_DEBUG, "BgFetcher is re-queueing failed "
"request for vb = %d seq = %lld key = %s retry = %d\n",
vbId, (*itr).first, (*dItr)->key.c_str(),
(*dItr)->getRetryCount());
++numRequeuedItems;
vb->queueBGFetchItem(*dItr, this, false);
}
}
}
if (numRequeuedItems) {
stats.numRemainingBgJobs.incr(numRequeuedItems);
}
}
bool BgFetcher::run(size_t tid) {
assert(tid > 0);
size_t num_fetched_items = 0;
pendingFetch.cas(true, false);
std::vector<uint16_t> bg_vbs;
LockHolder lh(queueMutex);
std::set<uint16_t>::iterator it = pendingVbs.begin();
for (; it != pendingVbs.end(); ++it) {
bg_vbs.push_back(*it);
}
pendingVbs.clear();
lh.unlock();
std::vector<uint16_t>::iterator ita = bg_vbs.begin();
for (; ita != bg_vbs.end(); ++ita) {
uint16_t vbId = *ita;
RCPtr<VBucket> vb = shard->getBucket(vbId);
if (vb && vb->getBGFetchItems(items2fetch)) {
doFetch(vbId);
num_fetched_items += items2fetch.size();
items2fetch.clear();
}
}
stats.numRemainingBgJobs.decr(num_fetched_items);
if (!pendingFetch.get()) {
// wait a bit until next fetch request arrives
double sleep = std::max(store->getBGFetchDelay(), sleepInterval);
IOManager::get()->snooze(taskId, sleep);
if (pendingFetch.get()) {
// check again a new fetch request could have arrived
// right before calling above snooze()
IOManager::get()->snooze(taskId, 0);
}
}
return true;
}
bool BgFetcher::pendingJob() {
std::vector<int> vbIds = shard->getVBuckets();
size_t numVbuckets = vbIds.size();
for (size_t i = 0; i < numVbuckets; ++i) {
RCPtr<VBucket> vb = shard->getBucket(vbIds[i]);
if (vb && vb->hasPendingBGFetchItems()) {
return true;
}
}
return false;
}