IndexedDB: Limit the size of a leveldb write buffer to minimize disk space.

third_party/leveldatabase/env_chromium_unittest.cc

Index: third_party/leveldatabase/env_chromium_unittest.cc
diff --git a/third_party/leveldatabase/env_chromium_unittest.cc b/third_party/leveldatabase/env_chromium_unittest.cc
index d4819e89804399a2235a874de704265070ba03b0..e656132a7c9196bfb01b29c6ad381db66029de07 100644
--- a/third_party/leveldatabase/env_chromium_unittest.cc
+++ b/third_party/leveldatabase/env_chromium_unittest.cc
@@ -26,6 +26,10 @@ using leveldb::WriteOptions;
 using leveldb_env::ChromiumEnv;
 using leveldb_env::MethodID;
 
+namespace leveldb_env {
+extern size_t WriteBufferSize(int64_t disk_space);

[michaeln, 2016/08/16 00:28:05]

Is including env_chromium.h not enough, the function is declared in there?

[cmumford, 2016/08/16 00:54:26]

I overloaded WriteBuferSize and this is the version that takes the disk space
(not the file/dir path). I did that to keep the public API clean. Still OK with
this approach, or do you think making this a public function is better?

[michaeln, 2016/08/16 19:41:23]

or maybe expose both functions in the .h file instead and give them different
names? WriteBufferSizeForDiskSize and WriteBufferSizeForPath or something like
that?

+}
+
 TEST(ErrorEncoding, OnlyAMethod) {
   const MethodID in_method = leveldb_env::kSequentialFileRead;
   const Status s = MakeIOError("Somefile.txt", "message", in_method);
@@ -169,4 +173,25 @@ TEST(ChromiumEnv, GetChildrenPriorResults) {
   EXPECT_EQ(1U, result.size());
 }
 
+TEST(ChromiumEnv, TestWriteBufferSize) {
+  // If can't get disk size, use leveldb defaults.
+  const int64_t MB = 1024 * 1024;
+  EXPECT_EQ(size_t(4 * MB), leveldb_env::WriteBufferSize(-1));
+
+  // A very small disk (check lower clamp value).
+  EXPECT_EQ(size_t(1 * MB), leveldb_env::WriteBufferSize(1 * MB));
+
+  // Some value on the linear equation between min and max.
+  EXPECT_EQ(size_t(2.5 * MB), leveldb_env::WriteBufferSize(25 * MB));
+
+  // The disk size equating to the max buffer size
+  EXPECT_EQ(size_t(4 * MB), leveldb_env::WriteBufferSize(40 * MB));
+
+  // Make sure sizes larger than 40MB are clamped to max buffer size.
+  EXPECT_EQ(size_t(4 * MB), leveldb_env::WriteBufferSize(80 * MB));
+
+  // Check for very large disk size (catch overflow).
+  EXPECT_EQ(size_t(4 * MB), leveldb_env::WriteBufferSize(100 * MB * MB));
+}
+
 int main(int argc, char** argv) { return base::TestSuite(argc, argv).Run(); }