C API: support get usage and pinned_usage for cache

Summary: Closes https://github.com/facebook/rocksdb/pull/1671

Differential Revision: D4327453

Pulled By: yiwu-arbug

fbshipit-source-id: bcdbc65

db/c.cc

@@ -2242,6 +2242,11 @@ void rocksdb_readoptions_set_readahead_size(
   opt->rep.readahead_size = v;
 }
 
+void rocksdb_readoptions_set_pin_data(rocksdb_readoptions_t* opt,
+                                      unsigned char v) {
+  opt->rep.pin_data = v;
+}
+
 rocksdb_writeoptions_t* rocksdb_writeoptions_create() {
   return new rocksdb_writeoptions_t;
 }
@@ -2309,6 +2314,14 @@ void rocksdb_cache_set_capacity(rocksdb_cache_t* cache, size_t capacity) {
   cache->rep->SetCapacity(capacity);
 }
 
+size_t rocksdb_cache_get_usage(rocksdb_cache_t* cache) {
+  return cache->rep->GetUsage();
+}
+
+size_t rocksdb_cache_get_pinned_usage(rocksdb_cache_t* cache) {
+  return cache->rep->GetPinnedUsage();
+}
+
 rocksdb_env_t* rocksdb_create_default_env() {
   rocksdb_env_t* result = new rocksdb_env_t;
   result->rep = Env::Default();

db/c_test.c

@@ -340,7 +340,7 @@ int main(int argc, char** argv) {
 
   roptions = rocksdb_readoptions_create();
   rocksdb_readoptions_set_verify_checksums(roptions, 1);
-  rocksdb_readoptions_set_fill_cache(roptions, 0);
+  rocksdb_readoptions_set_fill_cache(roptions, 1);
 
   woptions = rocksdb_writeoptions_create();
   rocksdb_writeoptions_set_sync(woptions, 1);
@@ -437,6 +437,24 @@ int main(int argc, char** argv) {
   rocksdb_compact_range_opt(db, coptions, "a", 1, "z", 1);
   CheckGet(db, roptions, "foo", "hello");
 
+  // Simple check cache usage
+  StartPhase("cache_usage");
+  {
+    rocksdb_readoptions_set_pin_data(roptions, 1);
+    rocksdb_iterator_t* iter = rocksdb_create_iterator(db, roptions);
+    rocksdb_iter_seek(iter, "foo", 3);
+
+    size_t usage = rocksdb_cache_get_usage(cache);
+    CheckCondition(usage > 0);
+
+    size_t pin_usage = rocksdb_cache_get_pinned_usage(cache);
+    CheckCondition(pin_usage > 0);
+
+    rocksdb_iter_next(iter);
+    rocksdb_iter_destroy(iter);
+    rocksdb_readoptions_set_pin_data(roptions, 0);
+  }
+
   StartPhase("writebatch");
   {
     rocksdb_writebatch_t* wb = rocksdb_writebatch_create();
@@ -795,9 +813,9 @@ int main(int argc, char** argv) {
   {
     rocksdb_close(db);
     rocksdb_destroy_db(options, dbname, &err);
-    CheckNoError(err)
+    CheckNoError(err);
 
-        rocksdb_options_t* db_options = rocksdb_options_create();
+    rocksdb_options_t* db_options = rocksdb_options_create();
     rocksdb_options_set_create_if_missing(db_options, 1);
     db = rocksdb_open(db_options, dbname, &err);
     CheckNoError(err)

include/rocksdb/c.h

@@ -875,6 +875,8 @@ extern ROCKSDB_LIBRARY_API void rocksdb_readoptions_set_tailing(
     rocksdb_readoptions_t*, unsigned char);
 extern ROCKSDB_LIBRARY_API void rocksdb_readoptions_set_readahead_size(
     rocksdb_readoptions_t*, size_t);
+extern ROCKSDB_LIBRARY_API void rocksdb_readoptions_set_pin_data(
+    rocksdb_readoptions_t*, unsigned char);
 
 /* Write options */
 
@@ -917,6 +919,10 @@ extern ROCKSDB_LIBRARY_API rocksdb_cache_t* rocksdb_cache_create_lru(
 extern ROCKSDB_LIBRARY_API void rocksdb_cache_destroy(rocksdb_cache_t* cache);
 extern ROCKSDB_LIBRARY_API void rocksdb_cache_set_capacity(
     rocksdb_cache_t* cache, size_t capacity);
+extern ROCKSDB_LIBRARY_API size_t
+rocksdb_cache_get_usage(rocksdb_cache_t* cache);
+extern ROCKSDB_LIBRARY_API size_t
+rocksdb_cache_get_pinned_usage(rocksdb_cache_t* cache);
 
 /* Env */