Expose cache occupancy via C API (#11327)

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/11327

Reviewed By: cbi42

Differential Revision: D44422225

Pulled By: ajkr

fbshipit-source-id: 3bfcf47290b3133c151bdfdd181896ba2e6be520

db/c.cc

@@ -4754,6 +4754,14 @@ size_t rocksdb_cache_get_pinned_usage(rocksdb_cache_t* cache) {
   return cache->rep->GetPinnedUsage();
 }
 
+size_t rocksdb_cache_get_table_address_count(const rocksdb_cache_t* cache) {
+  return cache->rep->GetTableAddressCount();
+}
+
+size_t rocksdb_cache_get_occupancy_count(const rocksdb_cache_t* cache) {
+  return cache->rep->GetOccupancyCount();
+}
+
 rocksdb_dbpath_t* rocksdb_dbpath_create(const char* path,
                                         uint64_t target_size) {
   rocksdb_dbpath_t* result = new rocksdb_dbpath_t;

include/rocksdb/c.h

@@ -2007,6 +2007,7 @@ extern ROCKSDB_LIBRARY_API rocksdb_cache_t*
 rocksdb_cache_create_lru_with_strict_capacity_limit(size_t capacity);
 extern ROCKSDB_LIBRARY_API rocksdb_cache_t* rocksdb_cache_create_lru_opts(
     rocksdb_lru_cache_options_t*);
+
 extern ROCKSDB_LIBRARY_API void rocksdb_cache_destroy(rocksdb_cache_t* cache);
 extern ROCKSDB_LIBRARY_API void rocksdb_cache_disown_data(
     rocksdb_cache_t* cache);
@@ -2018,8 +2019,13 @@ 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);
+extern ROCKSDB_LIBRARY_API size_t
+rocksdb_cache_get_table_address_count(const rocksdb_cache_t* cache);
+extern ROCKSDB_LIBRARY_API size_t
+rocksdb_cache_get_occupancy_count(const rocksdb_cache_t* cache);
 
 /* HyperClockCache */
+
 extern ROCKSDB_LIBRARY_API rocksdb_hyper_clock_cache_options_t*
 rocksdb_hyper_clock_cache_options_create(size_t capacity,
                                          size_t estimated_entry_charge);