contrib/leveldb/0002-Added-a-DB-SuspendCompations-and-DB-ResumeCompaction.patch
2021-10-31 13:08:32 +11:00

119 lines
3.9 KiB
Diff

From: Hiram Chirino <hiram@hiramchirino.com>
Date: Tue, 30 Oct 2012 16:56:52 -0400
Subject: [PATCH] Added a DB:SuspendCompations() and DB:ResumeCompactions()
methods. Fixes issue #184
https://code.google.com/p/leveldb/issues/detail?id=184
diff --git a/db/db_impl.cc b/db/db_impl.cc
index 1a4e459..ae7b96d 100644
--- a/db/db_impl.cc
+++ b/db/db_impl.cc
@@ -135,6 +135,9 @@ DBImpl::DBImpl(const Options& raw_options, const std::string& dbname)
table_cache_(new TableCache(dbname_, options_, TableCacheSize(options_))),
db_lock_(nullptr),
shutting_down_(false),
+ suspend_cv(&suspend_mutex),
+ suspend_count(0),
+ suspended(false),
background_work_finished_signal_(&mutex_),
mem_(nullptr),
imm_(nullptr),
@@ -1464,6 +1467,39 @@ void DBImpl::GetApproximateSizes(const Range* range, int n, uint64_t* sizes) {
v->Unref();
}
+void DBImpl::SuspendCompactions() {
+ MutexLock l(& suspend_mutex);
+ env_->Schedule(&SuspendWork, this);
+ suspend_count++;
+ while( !suspended ) {
+ suspend_cv.Wait();
+ }
+}
+void DBImpl::SuspendWork(void* db) {
+ reinterpret_cast<DBImpl*>(db)->SuspendCallback();
+}
+void DBImpl::SuspendCallback() {
+ MutexLock l(&suspend_mutex);
+ Log(options_.info_log, "Compactions suspended");
+ suspended = true;
+ suspend_cv.SignalAll();
+ while( suspend_count > 0 ) {
+ suspend_cv.Wait();
+ }
+ suspended = false;
+ suspend_cv.SignalAll();
+ Log(options_.info_log, "Compactions resumed");
+}
+void DBImpl::ResumeCompactions() {
+ MutexLock l(&suspend_mutex);
+ suspend_count--;
+ suspend_cv.SignalAll();
+ while( suspended ) {
+ suspend_cv.Wait();
+ }
+}
+
+
// Default implementations of convenience methods that subclasses of DB
// can call if they wish
Status DB::Put(const WriteOptions& opt, const Slice& key, const Slice& value) {
diff --git a/db/db_impl.h b/db/db_impl.h
index c7b0172..d955c2a 100644
--- a/db/db_impl.h
+++ b/db/db_impl.h
@@ -48,6 +48,8 @@ class DBImpl : public DB {
bool GetProperty(const Slice& property, std::string* value) override;
void GetApproximateSizes(const Range* range, int n, uint64_t* sizes) override;
void CompactRange(const Slice* begin, const Slice* end) override;
+ void SuspendCompactions() override;
+ void ResumeCompactions() override;
// Extra methods (for testing) that are not in the public DB interface
@@ -170,6 +172,13 @@ class DBImpl : public DB {
// Lock over the persistent DB state. Non-null iff successfully acquired.
FileLock* db_lock_;
+ port::Mutex suspend_mutex;
+ port::CondVar suspend_cv;
+ int suspend_count;
+ bool suspended;
+ static void SuspendWork(void* db);
+ void SuspendCallback();
+
// State below is protected by mutex_
port::Mutex mutex_;
std::atomic<bool> shutting_down_;
diff --git a/db/db_test.cc b/db/db_test.cc
index 908b41d..2e65370 100644
--- a/db/db_test.cc
+++ b/db/db_test.cc
@@ -2051,6 +2051,8 @@ class ModelDB : public DB {
};
explicit ModelDB(const Options& options) : options_(options) {}
+ virtual void SuspendCompactions() override {}
+ virtual void ResumeCompactions() override {}
~ModelDB() override = default;
Status Put(const WriteOptions& o, const Slice& k, const Slice& v) override {
return DB::Put(o, k, v);
diff --git a/include/leveldb/db.h b/include/leveldb/db.h
index a13d147..61c29c0 100644
--- a/include/leveldb/db.h
+++ b/include/leveldb/db.h
@@ -145,6 +145,12 @@ class LEVELDB_EXPORT DB {
// Therefore the following call will compact the entire database:
// db->CompactRange(nullptr, nullptr);
virtual void CompactRange(const Slice* begin, const Slice* end) = 0;
+
+ // Suspends the background compaction thread. This methods
+ // returns once suspended.
+ virtual void SuspendCompactions() = 0;
+ // Resumes a suspended background compation thread.
+ virtual void ResumeCompactions() = 0;
};
// Destroy the contents of the specified database.