wbtiger
/
foundationdb
mirror of https://github.com/apple/foundationdb.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Cherry picked #4678 changes onto #4780 to resolve conflicts.

This commit is contained in:
Steve Atherton 2021-05-05 22:02:44 -07:00
parent 799e7cc213
commit e0e3cd39f1
2 changed files with 114 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
fdbserver/IPager.h
View File

@ -125,7 +125,11 @@ public:
class IPagerSnapshot {
public:
virtual Future<Reference<const ArenaPage>> getPhysicalPage(LogicalPageID pageID, bool cacheable, bool nohit) = 0;
virtual Future<Reference<const ArenaPage>> getPhysicalPage(LogicalPageID pageID,
bool cacheable,
bool nohit,
bool* fromCache = nullptr) = 0;
virtual bool tryEvictPage(LogicalPageID id) = 0;
virtual Version getVersion() const = 0;
virtual Key getMetaKey() const = 0;
@ -176,7 +180,10 @@ public:
// Cacheable indicates that the page should be added to the page cache (if applicable?) as a result of this read.
// NoHit indicates that the read should not be considered a cache hit, such as when preloading pages that are
// considered likely to be needed soon.
virtual Future<Reference<ArenaPage>> readPage(LogicalPageID pageID, bool cacheable = true, bool noHit = false) = 0;
virtual Future<Reference<ArenaPage>> readPage(LogicalPageID pageID,
bool cacheable = true,
bool noHit = false,
bool* fromCache = nullptr) = 0;
// Get a snapshot of the metakey and all pages as of the version v which must be >= getOldestVersion()
// Note that snapshots at any version may still see the results of updatePage() calls.

134
fdbserver/VersionedBTree.actor.cpp
View File

@ -1108,6 +1108,22 @@ public:
return nullptr;
}
// Try to evict the item at index from cache
// Returns true if item is evicted or was not present in cache
bool tryEvict(const IndexType& index) {
auto i = cache.find(index);
if (i == cache.end() || !i->second.item.evictable()) {
return false;
}
Entry& toEvict = i->second;
if (toEvict.hits == 0) {
++g_redwoodMetrics.pagerEvictUnhit;
}
evictionOrder.erase(evictionOrder.iterator_to(toEvict));
cache.erase(toEvict.index);
return true;
}
// Get the object for i or create a new one.
// After a get(), the object for i is the last in evictionOrder.
// If noHit is set, do not consider this access to be cache hit if the object is present
@ -1769,14 +1785,29 @@ public:
return readPhysicalPage(self, pageID, true);
}
// Reads the most recent version of pageID, either previously committed or written using updatePage() in the current
// commit
Future<Reference<ArenaPage>> readPage(LogicalPageID pageID, bool cacheable, bool noHit = false) override {
bool tryEvictPage(LogicalPageID logicalID, Version v) {
PhysicalPageID physicalID = getPhysicalPageID(logicalID, v);
return pageCache.tryEvict(physicalID);
}
// Reads the most recent version of pageID, either previously committed or written using updatePage()
// in the current commit
// If cacheable is false then if fromCache is valid it will be set to true if the page is from cache, otherwise
// false. If cacheable is true, fromCache is ignored as the result is automatically from cache by virtue of being
// cacheable.
Future<Reference<ArenaPage>> readPage(LogicalPageID pageID,
bool cacheable,
bool noHit = false,
bool* fromCache = nullptr) override {
// Use cached page if present, without triggering a cache hit.
// Otherwise, read the page and return it but don't add it to the cache
if (!cacheable) {
debug_printf("DWALPager(%s) op=readUncached %s\n", filename.c_str(), toString(pageID).c_str());
PageCacheEntry* pCacheEntry = pageCache.getIfExists(pageID);
if (fromCache != nullptr) {
*fromCache = pCacheEntry != nullptr;
}
if (pCacheEntry != nullptr) {
debug_printf("DWALPager(%s) op=readUncachedHit %s\n", filename.c_str(), toString(pageID).c_str());
return pCacheEntry->readFuture;
@ -1804,14 +1835,14 @@ public:
return cacheEntry.readFuture;
}
Future<Reference<ArenaPage>> readPageAtVersion(LogicalPageID pageID, Version v, bool cacheable, bool noHit) {
PhysicalPageID getPhysicalPageID(LogicalPageID pageID, Version v) {
auto i = remappedPages.find(pageID);
if (i != remappedPages.end()) {
auto j = i->second.upper_bound(v);
if (j != i->second.begin()) {
--j;
debug_printf("DWALPager(%s) op=readAtVersionRemapped %s @%" PRId64 " -> %s\n",
debug_printf("DWALPager(%s) op=lookupRemapped %s @%" PRId64 " -> %s\n",
filename.c_str(),
toString(pageID).c_str(),
v,
@ -1820,13 +1851,22 @@ public:
ASSERT(pageID != invalidLogicalPageID);
}
} else {
debug_printf("DWALPager(%s) op=readAtVersionNotRemapped %s @%" PRId64 " (not remapped)\n",
debug_printf("DWALPager(%s) op=lookupNotRemapped %s @%" PRId64 " (not remapped)\n",
filename.c_str(),
toString(pageID).c_str(),
v);
}
return readPage(pageID, cacheable, noHit);
return (PhysicalPageID)pageID;
}
Future<Reference<ArenaPage>> readPageAtVersion(LogicalPageID logicalID,
Version v,
bool cacheable,
bool noHit,
bool* fromCache) {
PhysicalPageID physicalID = getPhysicalPageID(logicalID, v);
return readPage(physicalID, cacheable, noHit, fromCache);
}
// Get snapshot as of the most recent committed version of the pager
@ -2365,14 +2405,19 @@ public:
: pager(pager), metaKey(meta), version(version), expired(expiredFuture) {}
~DWALPagerSnapshot() override {}
Future<Reference<const ArenaPage>> getPhysicalPage(LogicalPageID pageID, bool cacheable, bool noHit) override {
Future<Reference<const ArenaPage>> getPhysicalPage(LogicalPageID pageID,
bool cacheable,
bool noHit,
bool* fromCache) override {
if (expired.isError()) {
throw expired.getError();
}
return map(pager->readPageAtVersion(pageID, version, cacheable, noHit),
[=](Reference<ArenaPage> p) { return Reference<const ArenaPage>(p); });
return map(pager->readPageAtVersion(pageID, version, cacheable, noHit, fromCache),
[=](Reference<ArenaPage> p) { return Reference<const ArenaPage>(std::move(p)); });
}
bool tryEvictPage(LogicalPageID id) override { return pager->tryEvictPage(id, version); }
Key getMetaKey() const override { return metaKey; }
Version getVersion() const override { return version; }
@ -3384,7 +3429,7 @@ public:
}
// Start reading the page, without caching
entries.push_back(
std::make_pair(q.get(), self->readPage(snapshot, q.get().pageID, nullptr, nullptr, true)));
std::make_pair(q.get(), self->readPage(snapshot, q.get().pageID, nullptr, nullptr, true, false)));
--toPop;
}
@ -4111,11 +4156,26 @@ private:
return records;
}
// Try to evict a BTree page from the pager cache.
// Returns true if, at the end of the call, the page is no longer in cache,
// so the caller can assume its IPage reference is the only one.
bool tryEvictPage(IPagerSnapshot* pager, BTreePageIDRef id) {
// If it's an oversized page, currently it cannot be in the cache
if (id.size() > 0) {
return true;
}
return pager->tryEvictPage(id.front());
}
ACTOR static Future<Reference<const ArenaPage>> readPage(Reference<IPagerSnapshot> snapshot,
BTreePageIDRef id,
const RedwoodRecordRef* lowerBound,
const RedwoodRecordRef* upperBound,
bool forLazyClear = false) {
bool forLazyClear = false,
bool cacheable = true,
bool* fromCache = nullptr)
{
if (!forLazyClear) {
debug_printf("readPage() op=read %s @%" PRId64 " lower=%s upper=%s\n",
toString(id).c_str(),
@ -4132,17 +4192,22 @@ private:
state Reference<const ArenaPage> page;
if (id.size() == 1) {
Reference<const ArenaPage> p = wait(snapshot->getPhysicalPage(id.front(), !forLazyClear, false));
page = p;
Reference<const ArenaPage> p = wait(snapshot->getPhysicalPage(id.front(), cacheable, false, fromCache));
page = std::move(p);
} else {
ASSERT(!id.empty());
std::vector<Future<Reference<const ArenaPage>>> reads;
for (auto& pageID : id) {
reads.push_back(snapshot->getPhysicalPage(pageID, !forLazyClear, false));
reads.push_back(snapshot->getPhysicalPage(pageID, cacheable, false));
}
std::vector<Reference<const ArenaPage>> pages = wait(getAll(reads));
// TODO: Cache reconstituted super pages somehow, perhaps with help from the Pager.
page = ArenaPage::concatPages(pages);
// In the current implementation, SuperPages are never present in the cache
if (fromCache != nullptr) {
*fromCache = false;
}
}
debug_printf("readPage() op=readComplete %s @%" PRId64 " \n", toString(id).c_str(), snapshot->getVersion());
@ -4152,7 +4217,7 @@ private:
metrics.pageReadExt += (id.size() - 1);
if (!forLazyClear && page->userData == nullptr) {
debug_printf("readPage() Creating Reader for %s @%" PRId64 " lower=%s upper=%s\n",
debug_printf("readPage() Creating Mirror for %s @%" PRId64 " lower=%s upper=%s\n",
toString(id).c_str(),
snapshot->getVersion(),
lowerBound->toString(false).c_str(),
@ -4166,7 +4231,7 @@ private:
pTreePage->toString(false, id, snapshot->getVersion(), lowerBound, upperBound).c_str());
}
return page;
return std::move(page);
}
static void preLoadPage(IPagerSnapshot* snapshot, BTreePageIDRef id) {
@ -4536,8 +4601,9 @@ private:
state Reference<FlowLock> commitReadLock = self->m_commitReadLock;
wait(commitReadLock->take());
state FlowLock::Releaser readLock(*commitReadLock);
state Reference<const ArenaPage> page =
wait(readPage(snapshot, rootID, update->decodeLowerBound, update->decodeUpperBound));
state bool fromCache = false;
state Reference<const ArenaPage> page = wait(
readPage(snapshot, rootID, update->decodeLowerBound, update->decodeUpperBound, false, false, &fromCache));
readLock.release();
state BTreePage* btPage = (BTreePage*)page->begin();
@ -4549,11 +4615,13 @@ private:
// though it is awkward to reason about.
state bool tryToUpdate = btPage->tree().numItems > 0 && update->boundariesNormal();
// If trying to update the page, we need to clone it so we don't modify the original.
// If trying to update the page and the page reference points into the cache,
// we need to clone it so we don't modify the original version of the page.
// TODO: Refactor DeltaTree::Mirror so it can be shared between different versions of pages
if (tryToUpdate) {
if (tryToUpdate && fromCache) {
page = self->cloneForUpdate(page);
btPage = (BTreePage*)page->begin();
fromCache = false;
}
debug_printf(
@ -5034,6 +5102,7 @@ private:
state bool detachChildren = (parentInfo->count > 2);
state bool forceUpdate = false;
// If no changes were made, but we should rewrite it to point directly to remapped child pages
if (!m.changesMade && detachChildren) {
debug_printf(
"%s Internal page forced rewrite because at least %d children have been updated in-place.\n",
@ -5041,12 +5110,17 @@ private:
parentInfo->count);
forceUpdate = true;
if (!m.updating) {
page = self->cloneForUpdate(page);
cursor = getCursor(page);
btPage = (BTreePage*)page->begin();
m.btPage = btPage;
m.m = cursor.mirror;
m.updating = true;
// Copy the page before modification if the page references the cache
if (fromCache) {
page = self->cloneForUpdate(page);
cursor = getCursor(page);
btPage = (BTreePage*)page->begin();
m.btPage = btPage;
m.m = cursor.mirror;
fromCache = false;
}
}
++g_redwoodMetrics.level(btPage->height).forceUpdate;
}
@ -5064,7 +5138,7 @@ private:
if (m.updating) {
// Page was updated in place (or being forced to be updated in place to update child page ids)
debug_printf(
"%s Internal page modified in-place tryUpdate=%d forceUpdate=%d detachChildren=%d\n",
"%s Internal page modified in-place tryToUpdate=%d forceUpdate=%d detachChildren=%d\n",
context.c_str(),
tryToUpdate,
forceUpdate,
@ -7653,12 +7727,14 @@ TEST_CASE("/redwood/correctness/unit/deltaTree/IntIntPair") {
pos = newPos;
}
double elapsed = timer() - start;
printf("Seek/skip test, jumpMax=%d, items=%d, oldSeek=%d useHint=%d: Elapsed %f s\n",
printf("Seek/skip test, count=%d jumpMax=%d, items=%d, oldSeek=%d useHint=%d: Elapsed %f seconds %.2f M/s\n",
count,
jumpMax,
items.size(),
old,
useHint,
elapsed);
elapsed,
double(count) / elapsed / 1e6);
};
// Compare seeking to nearby elements with and without hints, using the old and new SeekLessThanOrEqual methods.