MDEV-17171: RocksDB Tables do not have "Creation Date"

- Add SLEEP() calls to the testcase to make it really test that the
  time doesn't change.
- Always use .frm file creation time as a creation timestamp (attempts
  to re-use older create_time when the table DDL changes are not good
  because then create_time will change after server restart)
- Use the same method names as the upstream patch does
- Use std::atomic for m_update_time

storage/rocksdb/ha_rocksdb.cc

@@ -3010,7 +3010,7 @@ protected:
     time_t tm;
     tm = time(nullptr);
     for (auto &it : modified_tables) {
-      it->update_time = tm;
+      it->m_update_time = tm;
     }
     modified_tables.clear();
   }
@@ -11040,11 +11040,11 @@ int ha_rocksdb::info(uint flag) {
       }
     }
 
-    stats.create_time = m_tbl_def->get_creation_time();
+    stats.create_time = m_tbl_def->get_create_time();
   }
 
   if (flag & HA_STATUS_TIME) {
-    stats.update_time = m_tbl_def->update_time;
+    stats.update_time = m_tbl_def->m_update_time;
   }
 
   if (flag & HA_STATUS_ERRKEY) {

storage/rocksdb/mysql-test/rocksdb/r/show_table_status.result

@@ -75,7 +75,25 @@ select create_time, update_time into @create_tm, @update_tm
 from information_schema.tables 
 where table_schema=database() and table_name='t1';
 # Then, an in-place ALTER TABLE:
+select sleep(2);
+sleep(2)	0
 alter table t1 add key (a);
+# create_time will change as .frm file is rewritten:
+select
+create_time=@create_tm,
+update_time
+from information_schema.tables 
+where table_schema=database() and table_name='t1';
+create_time=@create_tm	0
+update_time	NULL
+# Check TRUNCATE TABLE
+insert into t1 values (10,10);
+select create_time, update_time into @create_tm, @update_tm
+from information_schema.tables 
+where table_schema=database() and table_name='t1';
+select sleep(2);
+sleep(2)	0
+truncate table t1;
 select
 create_time=@create_tm /* should not change */,
 update_time
@@ -86,13 +104,18 @@ update_time	NULL
 #
 # Check what is left after server restart
 #
+drop table t1;
+create table t1 (a int);
+insert into t1 values (1);
 # Save t1's creation time
 create table t2 as
 select create_time
 from information_schema.tables
 where table_schema=database() and table_name='t1';
+select sleep(2);
+sleep(2)	0
 select
-create_time=(select create_time from t2)  /* should change */,
+create_time=(select create_time from t2)  /* should not change */,
 update_time
 from information_schema.tables
 where table_schema=database() and table_name='t1';

storage/rocksdb/mysql-test/rocksdb/t/show_table_status.test

@@ -114,26 +114,49 @@ from information_schema.tables
 where table_schema=database() and table_name='t1';
 
 --echo # Then, an in-place ALTER TABLE:
+select sleep(2);
 alter table t1 add key (a);
 
+--echo # create_time will change as .frm file is rewritten:
+select
+  create_time=@create_tm,
+  update_time
+from information_schema.tables 
+where table_schema=database() and table_name='t1';
+
+--echo # Check TRUNCATE TABLE
+insert into t1 values (10,10);
+select create_time, update_time into @create_tm, @update_tm
+from information_schema.tables 
+where table_schema=database() and table_name='t1';
+
+select sleep(2);
+truncate table t1;
+
 select
   create_time=@create_tm /* should not change */,
   update_time
 from information_schema.tables 
 where table_schema=database() and table_name='t1';
 
+
 --echo #
 --echo # Check what is left after server restart
 --echo #
-
+drop table t1;
+create table t1 (a int);
+insert into t1 values (1);
 --echo # Save t1's creation time
 create table t2 as
 select create_time
 from information_schema.tables
 where table_schema=database() and table_name='t1';
 
+select sleep(2);
+--source include/restart_mysqld.inc
+
 select
-  create_time=(select create_time from t2)  /* should change */,
+  create_time=(select create_time from t2)  /* should not change */,
   update_time
 from information_schema.tables
 where table_schema=database() and table_name='t1';

storage/rocksdb/rdb_datadic.cc

@@ -3592,7 +3592,7 @@ bool Rdb_tbl_def::put_dict(Rdb_dict_manager *const dict,
   return false;
 }
 
-time_t Rdb_tbl_def::get_creation_time() {
+time_t Rdb_tbl_def::get_create_time() {
   time_t create_time = m_create_time;
 
   if (create_time == CREATE_TIME_UNKNOWN) {

storage/rocksdb/rdb_datadic.h

@@ -1093,27 +1093,24 @@ class Rdb_tbl_def {
 
   explicit Rdb_tbl_def(const std::string &name)
       : m_key_descr_arr(nullptr), m_hidden_pk_val(0), m_auto_incr_val(0),
-        m_create_time(CREATE_TIME_UNKNOWN) {
+        m_update_time(0), m_create_time(CREATE_TIME_UNKNOWN) {
     set_name(name);
   }
 
   Rdb_tbl_def(const char *const name, const size_t len)
       : m_key_descr_arr(nullptr), m_hidden_pk_val(0), m_auto_incr_val(0),
-        m_create_time(CREATE_TIME_UNKNOWN) {
+        m_update_time(0), m_create_time(CREATE_TIME_UNKNOWN) {
     set_name(std::string(name, len));
   }
 
   explicit Rdb_tbl_def(const rocksdb::Slice &slice, const size_t pos = 0)
       : m_key_descr_arr(nullptr), m_hidden_pk_val(0), m_auto_incr_val(0),
-        m_create_time(CREATE_TIME_UNKNOWN) {
+        m_update_time(0), m_create_time(CREATE_TIME_UNKNOWN) {
     set_name(std::string(slice.data() + pos, slice.size() - pos));
   }
 
   ~Rdb_tbl_def();
 
-  time_t get_creation_time();
-  time_t update_time = 0; // in-memory only value, maintained right here
-
   void check_and_set_read_free_rpl_table();
 
   /* Number of indexes */
@@ -1139,6 +1136,10 @@ class Rdb_tbl_def {
   const std::string &base_tablename() const { return m_tablename; }
   const std::string &base_partition() const { return m_partition; }
   GL_INDEX_ID get_autoincr_gl_index_id();
+
+  time_t get_create_time();
+  std::atomic<time_t> m_update_time; // in-memory only value
+
  private:
   const time_t CREATE_TIME_UNKNOWN= 1;
   // CREATE_TIME_UNKNOWN means "didn't try to read, yet"