Limited SQL features on TiDB Cloud
TiDB Cloud works with almost all workloads that TiDB supports, but there are some feature differences between TiDB Self-Managed and TiDB Cloud Dedicated/Serverless. This document describes the limitations of SQL features on TiDB Cloud. We are constantly filling in the feature gaps between TiDB Self-Managed and TiDB Cloud Dedicated/Serverless. If you require these features or capabilities in the gap, contact us for a feature request.
Statements
Placement and range management
| Statement | TiDB Cloud Dedicated | TiDB Cloud Serverless |
|---|---|---|
ALTER PLACEMENT POLICY | Supported | Not supported 1 |
CREATE PLACEMENT POLICY | Supported | Not supported 1 |
DROP PLACEMENT POLICY | Supported | Not supported 1 |
SHOW CREATE PLACEMENT POLICY | Supported | Not supported 1 |
SHOW PLACEMENT | Supported | Not supported 1 |
SHOW PLACEMENT FOR | Supported | Not supported 1 |
SHOW PLACEMENT LABELS | Supported | Not supported 1 |
SHOW TABLE REGIONS | Supported | Not supported 1 |
SPLIT REGION | Supported | Not supported 1 |
Resource groups
| Statement | TiDB Cloud Dedicated | TiDB Cloud Serverless |
|---|---|---|
ALTER RESOURCE GROUP | Supported | Not supported 2 |
CALIBRATE RESOURCE | Not supported | Not supported 2 |
CREATE RESOURCE GROUP | Supported | Not supported 2 |
DROP RESOURCE GROUP | Supported | Not supported 2 |
SET RESOURCE GROUP | Supported | Not supported 2 |
SHOW CREATE RESOURCE GROUP | Supported | Not supported 2 |
Others
| Statement | TiDB Cloud Dedicated | TiDB Cloud Serverless |
|---|---|---|
BACKUP | Supported | Not supported 3 |
SHOW BACKUPS | Supported | Not supported 3 |
RESTORE | Supported | Not supported 3 |
SHOW RESTORES | Supported | Not supported 3 |
ADMIN RESET TELEMETRY_ID | Supported | Telemetry is not supported on TiDB Cloud Serverless. |
ADMIN SHOW TELEMETRY | Not supported 4 | Not supported 4 |
ADMIN SHOW SLOW | Supported | Not supported 5 |
ADMIN PLUGINS ENABLE | Supported | Not supported 8 |
ADMIN PLUGINS DISABLE | Supported | Not supported 8 |
ALTER INSTANCE RELOAD TLS | Supported | TiDB Cloud Serverless automatically refreshes the TLS certificate. |
LOAD DATA INFILE | Only supports LOAD DATA LOCAL INFILE | Only supports LOAD DATA LOCAL INFILE |
CHANGE DRAINER | Not supported 7 | Not supported 7 |
CHANGE PUMP | Not supported 7 | Not supported 7 |
FLASHBACK CLUSTER | Supported | Not supported 3 |
LOAD STATS | Supported | Not supported |
SELECT ... INTO OUTFILE | Not supported 4 | Not supported 4 |
SET CONFIG | Not supported 4 | Not supported 4 |
SHOW CONFIG | Not supported 4 | Not supported 4 |
SHOW DRAINER STATUS | Not supported 7 | Not supported 7 |
SHOW PLUGINS | Supported | Not supported 8 |
SHOW PUMP STATUS | Not supported 7 | Not supported 7 |
SHUTDOWN | Not supported 4 | Not supported 4 |
PLAN REPLAYER | Supported | Supported in a different way11 |
Functions and operators
| Function and operator | TiDB Cloud Dedicated | TiDB Cloud Serverless |
|---|---|---|
SLEEP | No Limitation | The SLEEP() function has a limitation wherein it can only support a maximum sleep time of 300 seconds. |
System tables
| Database | Table | TiDB Cloud Dedicated | TiDB Cloud Serverless |
|---|---|---|---|
information_schema | ATTRIBUTES | Supported | Not supported 1 |
information_schema | CLUSTER_CONFIG | Not supported 4 | Not supported 4 |
information_schema | CLUSTER_HARDWARE | Not supported 4 | Not supported 4 |
information_schema | CLUSTER_INFO | Supported | Not supported 1 |
information_schema | CLUSTER_LOAD | Not supported 4 | Not supported 4 |
information_schema | CLUSTER_LOG | Not supported 4 | Not supported 4 |
information_schema | CLUSTER_SLOW_QUERY | Supported | Not supported 5 |
information_schema | CLUSTER_STATEMENTS_SUMMARY | Supported | Not supported 6 |
information_schema | CLUSTER_STATEMENTS_SUMMARY_EVICTED | Supported | Not supported 6 |
information_schema | CLUSTER_STATEMENTS_SUMMARY_HISTORY | Supported | Not supported 6 |
information_schema | CLUSTER_SYSTEMINFO | Not supported 4 | Not supported 4 |
information_schema | INSPECTION_RESULT | Not supported 4 | Not supported 4 |
information_schema | INSPECTION_RULES | Not supported 4 | Not supported 4 |
information_schema | INSPECTION_SUMMARY | Not supported 4 | Not supported 4 |
information_schema | METRICS_SUMMARY | Not supported 4 | Not supported 4 |
information_schema | METRICS_SUMMARY_BY_LABEL | Not supported 4 | Not supported 4 |
information_schema | METRICS_TABLES | Not supported 4 | Not supported 4 |
information_schema | PLACEMENT_POLICIES | Supported | Not supported 1 |
information_schema | RESOURCE_GROUPS | Supported | Not supported 2 |
information_schema | SLOW_QUERY | Supported | Not supported 5 |
information_schema | STATEMENTS_SUMMARY | Supported | Not supported 6 |
information_schema | STATEMENTS_SUMMARY_EVICTED | Supported | Not supported 6 |
information_schema | STATEMENTS_SUMMARY_HISTORY | Supported | Not supported 6 |
information_schema | TIDB_HOT_REGIONS | Not supported 4 | Not supported 4 |
information_schema | TIDB_HOT_REGIONS_HISTORY | Supported | Not supported 1 |
information_schema | TIDB_SERVERS_INFO | Supported | Not supported 1 |
information_schema | TIKV_REGION_PEERS | Supported | Not supported 1 |
information_schema | TIKV_REGION_STATUS | Supported | Not supported 1 |
information_schema | TIKV_STORE_STATUS | Supported | Not supported 1 |
performance_schema | pd_profile_allocs | Not supported 4 | Not supported 4 |
performance_schema | pd_profile_block | Not supported 4 | Not supported 4 |
performance_schema | pd_profile_cpu | Not supported 4 | Not supported 4 |
performance_schema | pd_profile_goroutines | Not supported 4 | Not supported 4 |
performance_schema | pd_profile_memory | Not supported 4 | Not supported 4 |
performance_schema | pd_profile_mutex | Not supported 4 | Not supported 4 |
performance_schema | tidb_profile_allocs | Not supported 4 | Not supported 4 |
performance_schema | tidb_profile_block | Not supported 4 | Not supported 4 |
performance_schema | tidb_profile_cpu | Not supported 4 | Not supported 4 |
performance_schema | tidb_profile_goroutines | Not supported 4 | Not supported 4 |
performance_schema | tidb_profile_memory | Not supported 4 | Not supported 4 |
performance_schema | tidb_profile_mutex | Not supported 4 | Not supported 4 |
performance_schema | tikv_profile_cpu | Not supported 4 | Not supported 4 |
mysql | expr_pushdown_blacklist | Not supported 4 | Not supported 4 |
mysql | gc_delete_range | Not supported 4 | Not supported 4 |
mysql | gc_delete_range_done | Not supported 4 | Not supported 4 |
mysql | opt_rule_blacklist | Not supported 4 | Not supported 4 |
mysql | tidb | Not supported 4 | Not supported 4 |
System variables
| Variable | TiDB Cloud Dedicated | TiDB Cloud Serverless |
|---|---|---|
datadir | No limitation | Not supported 1 |
interactive_timeout | No limitation | Read-only 10 |
max_allowed_packet | No limitation | Read-only 10 |
plugin_dir | No limitation | Not supported 8 |
plugin_load | No limitation | Not supported 8 |
require_secure_transport | Not supported 12 | Read-only 10 |
skip_name_resolve | No limitation | Read-only 10 |
sql_log_bin | No limitation | Read-only 10 |
tidb_cdc_write_source | No limitation | Read-only 10 |
tidb_check_mb4_value_in_utf8 | Not supported 4 | Not supported 4 |
tidb_config | Not supported 4 | Not supported 4 |
tidb_ddl_disk_quota | No limitation | Read-only 10 |
tidb_ddl_enable_fast_reorg | No limitation | Read-only 10 |
tidb_ddl_error_count_limit | No limitation | Read-only 10 |
tidb_ddl_flashback_concurrency | No limitation | Read-only 10 |
tidb_ddl_reorg_batch_size | No limitation | Read-only 10 |
tidb_ddl_reorg_priority | No limitation | Read-only 10 |
tidb_ddl_reorg_worker_cnt | No limitation | Read-only 10 |
tidb_enable_1pc | No limitation | Read-only 10 |
tidb_enable_async_commit | No limitation | Read-only 10 |
tidb_enable_auto_analyze | No limitation | Read-only 10 |
tidb_enable_collect_execution_info | Not supported 4 | Not supported 4 |
tidb_enable_ddl | No limitation | Read-only 10 |
tidb_enable_gc_aware_memory_track | No limitation | Read-only 10 |
tidb_enable_gogc_tuner | No limitation | Read-only 10 |
tidb_enable_local_txn | No limitation | Read-only 10 |
tidb_enable_resource_control | No limitation | Read-only 10 |
tidb_enable_slow_log | Not supported 4 | Not supported 4 |
tidb_enable_stmt_summary | No limitation | Read-only 10 |
tidb_enable_telemetry | Not supported 4 | Not supported 4 |
tidb_enable_top_sql | No limitation | Read-only 10 |
tidb_enable_tso_follower_proxy | No limitation | Read-only 10 |
tidb_expensive_query_time_threshold | Not supported 4 | Not supported 4 |
tidb_force_priority | Not supported 4 | Not supported 4 |
tidb_gc_concurrency | No limitation | Read-only 10 |
tidb_gc_enable | No limitation | Read-only 10 |
tidb_gc_life_time | No limitation | Read-only 10 |
tidb_gc_max_wait_time | No limitation | Read-only 10 |
tidb_gc_run_interval | No limitation | Read-only 10 |
tidb_gc_scan_lock_mode | No limitation | Read-only 10 |
tidb_general_log | Not supported 4 | Not supported 4 |
tidb_generate_binary_plan | No limitation | Read-only 10 |
tidb_gogc_tuner_threshold | No limitation | Read-only 10 |
tidb_guarantee_linearizability | No limitation | Read-only 10 |
tidb_isolation_read_engines | No limitation | Read-only 10 |
tidb_log_file_max_days | No limitation | Read-only 10 |
tidb_memory_usage_alarm_ratio | Not supported 4 | Not supported 4 |
tidb_metric_query_range_duration | Not supported 4 | Not supported 4 |
tidb_metric_query_step | Not supported 4 | Not supported 4 |
tidb_opt_write_row_id | Not supported 4 | Not supported 4 |
tidb_placement_mode | No limitation | Read-only 10 |
tidb_pprof_sql_cpu | Not supported 4 | Not supported 4 |
tidb_record_plan_in_slow_log | Not supported 4 | Not supported 4 |
tidb_redact_log | Not supported 4 | Not supported 4 |
tidb_restricted_read_only | Not supported 4 | Not supported 4 |
tidb_row_format_version | Not supported 4 | Not supported 4 |
tidb_scatter_region | No limitation | Read-only 10 |
tidb_server_memory_limit | No limitation | Read-only 10 |
tidb_server_memory_limit_gc_trigger | No limitation | Read-only 10 |
tidb_server_memory_limit_sess_min_size | No limitation | Read-only 10 |
tidb_simplified_metrics | No limitation | Read-only 10 |
tidb_slow_query_file | Not supported 4 | Not supported 4 |
tidb_slow_log_threshold | Not supported 4 | Not supported 4 |
tidb_slow_txn_log_threshold | Not supported 4 | Not supported 4 |
tidb_stats_load_sync_wait | No limitation | Read-only 10 |
tidb_stmt_summary_history_size | No limitation | Read-only 10 |
tidb_stmt_summary_internal_query | No limitation | Read-only 10 |
tidb_stmt_summary_max_sql_length | No limitation | Read-only 10 |
tidb_stmt_summary_max_stmt_count | No limitation | Read-only 10 |
tidb_stmt_summary_refresh_interval | No limitation | Read-only 10 |
tidb_sysproc_scan_concurrency | No limitation | Read-only 10 |
tidb_top_sql_max_meta_count | Not supported 4 | Not supported 4 |
tidb_top_sql_max_time_series_count | Not supported 4 | Not supported 4 |
tidb_tso_client_batch_max_wait_time | No limitation | Read-only 10 |
tidb_ttl_delete_batch_size | No limitation | Read-only 10 |
tidb_ttl_delete_rate_limit | No limitation | Read-only 10 |
tidb_ttl_delete_worker_count | No limitation | Read-only 10 |
tidb_ttl_job_schedule_window_end_time | No limitation | Read-only 10 |
tidb_ttl_job_schedule_window_start_time | No limitation | Read-only 10 |
tidb_ttl_running_tasks | No limitation | Read-only 10 |
tidb_ttl_scan_batch_size | No limitation | Read-only 10 |
tidb_ttl_scan_worker_count | No limitation | Read-only 10 |
tidb_txn_mode | No limitation | Read-only 10 |
tidb_wait_split_region_finish | No limitation | Read-only 10 |
tidb_wait_split_region_timeout | No limitation | Read-only 10 |
txn_scope | No limitation | Read-only 10 |
validate_password.enable | No limitation | Always enabled 9 |
validate_password.length | No limitation | At least 8 9 |
validate_password.mixed_case_count | No limitation | At least 1 9 |
validate_password.number_count | No limitation | At least 1 9 |
validate_password.policy | No limitation | Can only be MEDIUM or STRONG 9 |
validate_password.special_char_count | No limitation | At least 1 9 |
wait_timeout | No limitation | Read-only 10 |
- Configuring data placement is not supported on TiDB Cloud Serverless.↩
- Configuring resource groups is not supported on TiDB Cloud Serverless.↩
- TiDB Cloud Serverless does not support downloading the file exported by
PLAN REPLAYERthrough${tidb-server-status-port}as in the example. Instead, TiDB Cloud Serverless generates a presigned URL for you to download the file. Note that this URL remains valid for 10 hours after generation.↩ - The feature is unavailable in Security Enhanced Mode (SEM).↩
- Drainer and Pump are not supported on TiDB Cloud.↩
- Plugin is not supported on TiDB Cloud Serverless.↩
- To perform Back up and Restore operations on TiDB Cloud Serverless, you can use the TiDB Cloud console instead.↩
- To track Slow Query on TiDB Cloud Serverless, you can use the TiDB Cloud console instead.↩
- To perform Statement Analysis on TiDB Cloud Serverless, you can use the TiDB Cloud console instead.↩
- The variable is read-only on TiDB Cloud Serverless.↩
- TiDB Cloud Serverless enforces strong password policy.↩
- Not supported. Enabling
require_secure_transportfor TiDB Cloud Dedicated clusters will result in SQL client connection failures.↩