Add drop indexes to information_schema

Summary:
Add drop indexes to information_schema

Test Plan:
  mysql-test/suite/rocksdb/t/information_schema.test
  mysql-test/suite/rocksdb_sys_vars/t/rocksdb_pause_background_work_basic.test

Reviewers: jkedgar, hermanlee4

Reviewed By: hermanlee4

Subscribers: webscalesql-eng

Differential Revision: https://reviews.facebook.net/D50457

Author: reidHoruff

storage/rocksdb/ha_rocksdb.cc

@@ -211,6 +211,28 @@ rocksdb_drop_index_wakeup_thread(THD* thd,
   }
 }
 
+static my_bool rocksdb_pause_background_work = 0;
+static mysql_mutex_t pause_background_work_mutex;
+
+static void
+rocksdb_set_pause_background_work(THD* thd,
+                                 struct st_mysql_sys_var* var,
+                                 void* var_ptr,
+                                 const void* save)
+{
+  mysql_mutex_lock(&pause_background_work_mutex);
+  bool pause_requested = *static_cast<const bool*>(save);
+  if (rocksdb_pause_background_work != pause_requested) {
+    if (pause_requested) {
+      rdb->PauseBackgroundWork();
+    } else {
+      rdb->ContinueBackgroundWork();
+    }
+    rocksdb_pause_background_work = pause_requested;
+  }
+  mysql_mutex_unlock(&pause_background_work_mutex);
+}
+
 static void
 set_compaction_options(THD* thd,
                        struct st_mysql_sys_var* var,
@@ -679,6 +701,12 @@ static MYSQL_SYSVAR_BOOL(signal_drop_index_thread,
   "Wake up drop index thread",
   NULL, rocksdb_drop_index_wakeup_thread, FALSE);
 
+static MYSQL_SYSVAR_BOOL(pause_background_work,
+  rocksdb_pause_background_work,
+  PLUGIN_VAR_RQCMDARG,
+  "Disable all rocksdb background operations",
+  nullptr, rocksdb_set_pause_background_work, FALSE);
+
 static MYSQL_SYSVAR_BOOL(strict_collation_check,
   rocksdb_strict_collation_check,
   PLUGIN_VAR_RQCMDARG,
@@ -840,6 +868,7 @@ static struct st_mysql_sys_var* rocksdb_system_variables[]= {
 
   MYSQL_SYSVAR(compact_cf),
   MYSQL_SYSVAR(signal_drop_index_thread),
+  MYSQL_SYSVAR(pause_background_work),
   MYSQL_SYSVAR(strict_collation_check),
   MYSQL_SYSVAR(strict_collation_exceptions),
   MYSQL_SYSVAR(collect_sst_properties),
@@ -906,7 +935,8 @@ static PSI_stage_info *all_rocksdb_stages[]=
 static PSI_mutex_key ex_key_mutex_example, ex_key_mutex_ROCKSDB_SHARE_mutex,
   key_mutex_background, key_mutex_stop_background,
   key_mutex_drop_index, key_drop_index_interrupt_mutex,
-  key_mutex_snapshot, key_mutex_collation_exception_list;
+  key_mutex_snapshot, key_mutex_collation_exception_list,
+  key_mutex_pause_background_work;
 
 static PSI_mutex_info all_rocksdb_mutexes[]=
 {
@@ -919,6 +949,7 @@ static PSI_mutex_info all_rocksdb_mutexes[]=
   { &key_mutex_snapshot, "snapshot", PSI_FLAG_GLOBAL},
   { &key_mutex_collation_exception_list, "collation_exception_list",
       PSI_FLAG_GLOBAL},
+  { &key_mutex_pause_background_work, "pause background work", PSI_FLAG_GLOBAL},
 };
 
 PSI_cond_key key_cond_stop, key_drop_index_interrupt_cond;
@@ -1919,6 +1950,8 @@ static int rocksdb_init_func(void *p)
   mysql_mutex_init(key_mutex_snapshot, &snapshot_mutex, MY_MUTEX_INIT_FAST);
   mysql_mutex_init(key_mutex_collation_exception_list,
                    &collation_exception_list_mutex, MY_MUTEX_INIT_FAST);
+  mysql_mutex_init(key_mutex_pause_background_work,
+                   &pause_background_work_mutex, MY_MUTEX_INIT_FAST);
   mysql_cond_init(key_cond_stop, &stop_cond, NULL);
   (void) my_hash_init(&rocksdb_open_tables,system_charset_info,32,0,0,
                       (my_hash_get_key) rocksdb_get_key,0,0);
@@ -1947,6 +1980,8 @@ static int rocksdb_init_func(void *p)
                        HTON_CAN_RECREATE;
 
   mysql_mutex_init(key_mutex_drop_index, &drop_index_mutex, MY_MUTEX_INIT_FAST);
+  mysql_mutex_init(key_drop_index_interrupt_mutex, &drop_index_interrupt_mutex,
+                   MY_MUTEX_INIT_FAST);
   mysql_mutex_init(key_drop_index_interrupt_mutex, &drop_index_interrupt_mutex,
                    MY_MUTEX_INIT_FAST);
   mysql_cond_init(key_drop_index_interrupt_cond, &drop_index_interrupt_cond, NULL);
@@ -2148,6 +2183,10 @@ static int rocksdb_init_func(void *p)
 
   collation_exception_list = split(rocksdb_strict_collation_exceptions, ',');
 
+  if (rocksdb_pause_background_work) {
+    rdb->PauseBackgroundWork();
+  }
+
   sql_print_information("RocksDB instance opened");
   DBUG_RETURN(0);
 }
@@ -2186,6 +2225,7 @@ static int rocksdb_done_func(void *p)
   mysql_mutex_destroy(&collation_exception_list_mutex);
   mysql_mutex_destroy(&snapshot_mutex);
   mysql_mutex_destroy(&rocksdb_mutex);
+  mysql_mutex_destroy(&pause_background_work_mutex);
 
   ddl_manager.cleanup();
   binlog_manager.cleanup();

storage/rocksdb/rdb_datadic.h

@@ -765,7 +765,7 @@ class Binlog_info_manager
   key: RDBSE_KEYDEF::BINLOG_INFO_INDEX_NUMBER (0x4)
   value: version, {binlog_name,binlog_pos,binlog_gtid}
 
-  5. Ongoing drop index entry (not implemented yet)
+  5. Ongoing drop index entry
   key: RDBSE_KEYDEF::DDL_DROP_INDEX_ONGOING(0x5) + cf_id + index_id
   value: version
 

storage/rocksdb/rdb_i_s.cc

@@ -633,6 +633,7 @@ static int i_s_rocksdb_global_info_fill_table(THD *thd,
   DBUG_ENTER("i_s_rocksdb_global_info_fill_table");
   static const uint32_t INT_BUF_LEN = 21;
   static const uint32_t GTID_BUF_LEN = 60;
+  static const uint32_t CF_ID_INDEX_BUF_LEN = 60;
 
   int ret= 0;
 
@@ -678,6 +679,20 @@ static int i_s_rocksdb_global_info_fill_table(THD *thd,
       break;
   }
 
+  /* DDL_DROP_INDEX_ONGOING */
+  std::vector<GL_INDEX_ID> gl_index_ids;
+  dict_manager->get_drop_indexes_ongoing(&gl_index_ids);
+  char cf_id_index_buf[CF_ID_INDEX_BUF_LEN]= {0};
+  for (auto gl_index_id : gl_index_ids) {
+    snprintf(cf_id_index_buf, CF_ID_INDEX_BUF_LEN, "cf_id:%u,index_id:%u",
+        gl_index_id.cf_id, gl_index_id.index_id);
+    ret |= global_info_fill_row(thd, tables, "DDL_DROP_INDEX_ONGOING",
+        cf_id_index_buf, "");
+
+    if (ret)
+      break;
+  }
+
   DBUG_RETURN(ret);
 }