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Limited SQL Features on TiDB Cloud
Learn about the limited SQL features on TiDB Cloud.

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-Hosted and TiDB Dedicated/Serverless. This document describes the limitations of SQL features on TiDB Cloud. We are constantly filling in the feature gaps between TiDB Self-Hosted and TiDB 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 Dedicated TiDB 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 Dedicated TiDB 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 Dedicated TiDB 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 Serverless.
ADMIN SHOW TELEMETRY Not supported 4 Not supported 4
ADMIN SHOW SLOW Supported Not supported 5
ADMIN PLUGINS ENABLE Supported Not supported 6
ADMIN PLUGINS DISABLE Supported Not supported 6
ALTER INSTANCE RELOAD TLS Supported TiDB 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 6
SHOW PUMP STATUS Not supported 7 Not supported 7
SHUTDOWN Not supported 4 Not supported 4

Functions and operators

Function and operator TiDB Dedicated TiDB 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 Dedicated TiDB 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 8
information_schema CLUSTER_STATEMENTS_SUMMARY_EVICTED Supported Not supported 8
information_schema CLUSTER_STATEMENTS_SUMMARY_HISTORY Supported Not supported 8
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 8
information_schema STATEMENTS_SUMMARY_EVICTED Supported Not supported 8
information_schema STATEMENTS_SUMMARY_HISTORY Supported Not supported 8
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 TIFLASH_SEGMENTS Supported Not supported 1
information_schema TIFLASH_TABLES 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
mysql tidb_ttl_job_history Supported Not supported 9
mysql tidb_ttl_table_status Supported Not supported 9
mysql tidb_ttl_task Supported Not supported 9

System variables

Variable TiDB Dedicated TiDB 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 6
plugin_load No limitation Not supported 6
require_secure_transport Not supported 11 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 9
tidb_ttl_delete_rate_limit No limitation Read-only 9
tidb_ttl_delete_worker_count No limitation Read-only 9
tidb_ttl_job_enable No limitation Read-only 9
tidb_ttl_job_schedule_window_end_time No limitation Read-only 9
tidb_ttl_job_schedule_window_start_time No limitation Read-only 9
tidb_ttl_running_tasks No limitation Read-only 9
tidb_ttl_scan_batch_size No limitation Read-only 9
tidb_ttl_scan_worker_count No limitation Read-only 9
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 12
validate_password.length No limitation At least 8 12
validate_password.mixed_case_count No limitation At least 1 12
validate_password.number_count No limitation At least 1 12
validate_password.policy No limitation Can only be MEDIUM or STRONG 12
validate_password.special_char_count No limitation At least 1 12
wait_timeout No limitation Read-only 10

Footnotes

  1. Configuring data placement is not supported on TiDB Serverless. 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

  2. Configuring resource groups is not supported on TiDB Serverless. 2 3 4 5 6 7

  3. To perform Back up and Restore operations on TiDB Serverless, you can use the TiDB Cloud console instead. 2 3 4 5

  4. The feature is unavailable in Security Enhanced Mode (SEM). 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114

  5. To track Slow Query on TiDB Serverless, you can use the TiDB Cloud console instead. 2 3

  6. Plugin is not supported on TiDB Serverless. 2 3 4 5

  7. Drainer and Pump are not supported on TiDB Cloud. 2 3 4 5 6 7 8

  8. To perform Statement Analysis on TiDB Serverless, you can use the TiDB Cloud console instead. 2 3 4 5 6

  9. Time to live (TTL) is currently unavailable on TiDB Serverless. 2 3 4 5 6 7 8 9 10 11 12

  10. The variable is read-only on TiDB Serverless. 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

  11. Not supported. Enabling require_secure_transport for TiDB Dedicated clusters will result in SQL client connection failures.

  12. TiDB Serverless enforces strong password policy. 2 3 4 5 6