Merge pull request #727 from jsteemann/micro-optimization

Micro optimizations

db/dbformat.h

@@ -282,7 +282,7 @@ class IterKey {
     return Slice(key_, key_size_ - 8);
   }
 
-  size_t Size() { return key_size_; }
+  size_t Size() const { return key_size_; }
 
   void Clear() { key_size_ = 0; }
 
@@ -302,7 +302,7 @@ class IterKey {
       char* p = new char[total_size];
       memcpy(p, key_, shared_len);
 
-      if (key_ != nullptr && key_ != space_) {
+      if (key_ != space_) {
         delete[] key_;
       }
 
@@ -388,10 +388,10 @@ class IterKey {
   char space_[32];  // Avoid allocation for short keys
 
   void ResetBuffer() {
-    if (key_ != nullptr && key_ != space_) {
+    if (key_ != space_) {
       delete[] key_;
+      key_ = space_;
     }
-    key_ = space_;
     buf_size_ = sizeof(space_);
     key_size_ = 0;
   }

include/rocksdb/write_batch.h

@@ -206,7 +206,8 @@ class WriteBatch : public WriteBatchBase {
   WriteBatch* GetWriteBatch() override { return this; }
 
   // Constructor with a serialized string object
-  explicit WriteBatch(std::string rep) : save_points_(nullptr), rep_(rep) {}
+  explicit WriteBatch(const std::string& rep)
+      : save_points_(nullptr), rep_(rep) {}
 
  private:
   friend class WriteBatchInternal;

util/env_posix.cc

@@ -614,19 +614,18 @@ class PosixWritableFile : public WritableFile {
   virtual Status Append(const Slice& data) override {
     const char* src = data.data();
     size_t left = data.size();
-    Status s;
-      while (left != 0) {
-        ssize_t done = write(fd_, src, left);
-        if (done < 0) {
-          if (errno == EINTR) {
-            continue;
-          }
-          return IOError(filename_, errno);
+    while (left != 0) {
+      ssize_t done = write(fd_, src, left);
+      if (done < 0) {
+        if (errno == EINTR) {
+          continue;
         }
-        left -= done;
-        src += done;
+        return IOError(filename_, errno);
       }
-      filesize_ += data.size();
+      left -= done;
+      src += done;
+    }
+    filesize_ += data.size();
     return Status::OK();
   }