你好，想问下这个sql 系统默认的吗？出现频率特别高，执行时间长
Time: 2020-07-10T04:30:44.54145739+08:00
Txn_start_ts: 417942765151191044
Query_time: 1521.07976719
Parse_time: 0.000295926
Compile_time: 0.001609564
Process_time: 0.004 Wait_time: 46.074 Backoff_time: 34.845 Request_count: 2 Total_keys: 4 Process_keys: 3
Index_names: [GLOBAL_VARIABLES:PRIMARY]
Is_internal: true
Digest: 4ef13ef1c364f2ae589706ea4178c0196bcb9add519de2eaabcbcfa7e293dfeb
Stats: GLOBAL_VARIABLES:pseudo
Num_cop_tasks: 2
Cop_proc_avg: 0.002 Cop_proc_p90: 0.003 Cop_proc_max: 0.003 Cop_proc_addr: 192.168.241.56:20160
Cop_wait_avg: 23.037 Cop_wait_p90: 27.559 Cop_wait_max: 27.559 Cop_wait_addr: 192.168.241.56:20160
Mem_max: 10336
Prepared: false
Has_more_results: false
Succ: true
Plan: tidb_decode_plan('yRlQMAkzMV83CTAJNTUJCjEJMTNfNQkxAQ10dGFibGU6R0xPQkFMX1ZBUklBQkxFUywgaW5kZXg6ERFwX05BTUUsIHJhbmdlOlsiYXV0b19pbmNyZW1lbnQZCgQiLGYbAAhdLCBCOQAQb2Zmc2
VKNgANGBUzEGNvbW1pESgNDQUdWGJsb2NrX2VuY3J5cHRpb25fbW9kZSIsWhgABTMcaW5ub2RiX2wBOSh3YWl0X3RpbWVvdQFeYhsADTkgdGVyYWN0aXZlMjQARhYABS88bWF4X2FsbG93ZWRfcGFjawXoShUAFS0QZXhlY3UFxQ
GSBCIsBS06FQAVLURwcmVwYXJlZF9zdG10X2NvdW4BwQFfThoABTcIc3FsMR8VCwUZLHRpZGJfYmFja29mZikYCGZhcwFPWhkARjUAEHdlaWdoQjIADRYZL1xjb25zdHJhaW50X2NoZWNrX2luX3BsYWMB7QVsZiEAGUUgZGRsX2
Vycm9yCfYIX2xpSRsFQVYdADY9ADhyZW9yZ19iYXRjaF9zaXoVfQE8QhwATjsAHHdvcmtlcl9jJXMVdwk7HRwdOwRpc2FmEF90eG5fZTsYcmV0cnkiLA09Vh4AMj8AAHQhsgxzY2FuISMYY3VycmVuYy5BAFYgABlDBGVuBYEcY2
FzY2FkZXMhdgxubmVyEYNeHwBCQQBBGRRfYW5hbHk5OA09MhsAQjkARacQc3VtbWEZ+Q05MhsAQjkAhaAUX3BhcnRpYRw6sgA+HgBCPwAod2luZG93X2Z1bmNKPwA+HgAdPxB4cGVuc2HrEHF1ZXJ5ZZMkX3RocmVzaG9sZBWGdi
YAGU8caGFzaF9qb2lSwAFWHQA2PQAgYWdnX2ZpbmFsTgECAUFWIQBGRQAlSnZHAE4jABlJxRkJzEZEA1YdAD49ABRsb29rdXBOygAJQEogAFpDAF5TATJIAEIlAFpNAC4NBDJBAAUZPjUACHNlciFIXpUDCUFeJQAuTQAAaaEOCH
VuawlnACyJFQBpOhcAHTEMc29sYUHMMF9yZWFkX2VuZ2luZXMVOFYeABk/wSMAY0JvADoWADYvACxkZWx0YV9zY2hlbWGpdRFuATdKHgAZPwRvcMGdAG6RshRfZmFjdG+Vd1oeAD4/AAxwY3B1UjoALhkAPjUACHJyZS0nCGV4cF
I+AFIiAGZHAEL9Awm+GUYZITpFAFa+ABkWNi8ADGRlc2NKsAAuFwA2MQAgaW5zdWJxX3RvSekYYW5kX2FnZzGjAaZaIgA2RwAQbWVtb3JOogE2GQA2NQAIbmV0wfJKsAA6GgA2NwBlNUYMAi4XABkxEHByb2plpb5OMgRaHgAZP+
VsNiYILhMAGSkgc2tpcF91dGY4Fp0IACJtij4XAB0xCHRtdNHUEF9oaXN0IUCFLBE7YiEAWkUACHJlZsFiBF9pDlUKCHZhbFJJAEIlAC5NAAhvcmU27AABlhETGSkOiggaKwsSwQgVEA0jFG1lX3pvbhYbCREMBRs6MgsyDwCAXS
wga2VlcCBvcmRlcjpmYWxzZSwgc3RhdHM6cHNldWRvDnkMCDBfNnZ5DHpDAA==’)
Plan_digest: 7361d55cb1482496b909e193e5c0fc449ded2a91c24d7387d876f10e9600d8ab
select HIGH_PRIORITY * from mysql.global_variables where variable_name in (‘autocommit’, ‘sql_mode’, ‘max_allowed_packet’, ‘time_zone’, ‘block_encryption_mode’, ‘wait_timeo
ut’, ‘interactive_timeout’, ‘max_prepared_stmt_count’, ‘auto_increment_increment’, ‘auto_increment_offset’, ‘max_execution_time’, ‘innodb_lock_wait_timeout’, ‘tidb_skip_utf
8_check’, ‘tidb_index_join_batch_size’, ‘tidb_index_lookup_size’, ‘tidb_index_lookup_concurrency’, ‘tidb_index_lookup_join_concurrency’, 'tidb_index_serial_scan_concurrency
', ‘tidb_hash_join_concurrency’, ‘tidb_projection_concurrency’, ‘tidb_hashagg_partial_concurrency’, ‘tidb_hashagg_final_concurrency’, ‘tidb_backoff_lock_fast’, ‘tidb_backof
f_weight’, ‘tidb_constraint_check_in_place’, ‘tidb_ddl_reorg_worker_cnt’, ‘tidb_ddl_reorg_batch_size’, ‘tidb_ddl_error_count_limit’, ‘tidb_opt_insubq_to_join_and_agg’, ‘tid
b_opt_correlation_threshold’, ‘tidb_opt_correlation_exp_factor’, ‘tidb_opt_cpu_factor’, ‘tidb_opt_copcpu_factor’, ‘tidb_opt_network_factor’, ‘tidb_opt_scan_factor’, ‘tidb_o
pt_desc_factor’, ‘tidb_opt_memory_factor’, ‘tidb_opt_concurrency_factor’, ‘tidb_distsql_scan_concurrency’, ‘tidb_init_chunk_size’, ‘tidb_max_chunk_size’, ‘tidb_enable_casca
des_planner’, ‘tidb_retry_limit’, ‘tidb_disable_txn_auto_retry’, ‘tidb_enable_window_function’, ‘tidb_enable_table_partition’, ‘tidb_enable_fast_analyze’, ‘tidb_expensive_q
uery_time_threshold’, ‘tidb_txn_mode’, ‘tidb_enable_stmt_summary’, ‘tidb_stmt_summary_refresh_interval’, ‘tidb_stmt_summary_history_size’, ‘tidb_max_delta_schema_count’, ‘t
idb_store_limit’, ‘tidb_isolation_read_engines’);