•These system variables: query_cache_limit , query_cache_min_res_unit , query_cache_size , query_cache_type , query_cache_wlock_invalidate . 

•These status variables: Qcache_free_blocks , Qcache_free_memory , Qcache_hits , Qcache_inserts , Qcache_lowmem_prunes , Qcache_not_cached , Qcache_queries_in_cache , Qcache_total_blocks . 

•These thread states: checking privileges on cached query , checking query cache for query , invalidating query cache entries , sending cached result to client , storing result in query cache , Waiting for query cache lock . 

•The SQL_CACHE SELECT  modifier. 

These deprecated query cache items remain deprecated, but have no effect; expect them to be removed in a future MySQL release: 

•The SQL_NO_CACHE SELECT  modifier. 

•The ndb_cache_check_time  system variable. 

The have_query_cache  system variable remains deprecated, and always has a value of NO ; expect it to be removed in a future MySQL release. 

•The data dictionary provides information about database objects, so the server no longer checks directory names in the data directory to find databases. Consequently, the --ignore-db-dir  option and ignore_db_dirs  system variables are extraneous and are removed. 

•The DDL log, also known as the metadata log, has been removed. Beginning with MySQL 8.0.3, this functionality is handled by the data dictionary innodb_ddl_log  table. See Viewing DDL Logs. 

•The tx_isolation  and tx_read_only  system variables have been removed. Use transaction_isolation  and transaction_read_only  instead. 

•The sync_frm  system variable has been removed because .frm  files have become obsolete. 

•The secure_auth  system variable and --secure-auth  client option have been removed. The MYSQL_SECURE_AUTH  option for the mysql_options() C API function was removed. 

•The multi_range_count  system variable is removed. 

•The log_warnings  system variable and --log-warnings  server option have been removed. Use the log_error_verbosity  system variable instead. 

•The global scope for the sql_log_bin  system variable was removed. sql_log_bin  has session scope only, and applications that rely on accessing @@GLOBAL.sql_log_bin  should be adjusted. 

•The metadata_locks_cache_size  and metadata_locks_hash_instances  system variables are removed. 

•The unused date_format , datetime_format , time_format , and max_tmp_tables  system variables are removed. 

•These deprecated compatibility SQL modes are removed: DB2 , MAXDB , MSSQL , MYSQL323 , MYSQL40 , ORACLE , POSTGRESQL , NO_FIELD_OPTIONS , NO_KEY_OPTIONS , NO_TABLE_OPTIONS . They can no 

