ينشئ QUOTA يمكن إسنادها إلى مستخدم أو دور.
الصيغة:
CREATE QUOTA [IF NOT EXISTS | OR REPLACE] name [ON CLUSTER cluster_name]
[IN access_storage_type]
[KEYED BY {user_name | ip_address | forwarded_ip_address | client_key | client_key,user_name | client_key,ip_address | normalized_query_hash} | NOT KEYED]
[IPV4_PREFIX_BITS number]
[IPV6_PREFIX_BITS number]
[FOR [RANDOMIZED] INTERVAL number {second | minute | hour | day | week | month | quarter | year}
{MAX { {queries | query_selects | query_inserts | errors | result_rows | result_bytes | read_rows | read_bytes | written_bytes | execution_time | failed_sequential_authentications | queries_per_normalized_hash} = number } [,...] |
NO LIMITS | TRACKING ONLY} [,...]]
[TO {role [,...] | ALL | ALL EXCEPT role [,...]}]
user_name, ip_address, forwarded_ip_address, client_key, client_key, user_name, client_key, ip_address, و normalized_query_hash تتوافق مع الحقول في جدول system.quotas.
لا يمكن استخدام الخيارين IPV4_PREFIX_BITS و IPV6_PREFIX_BITS إلا عندما تكون KEYED BY هي ip_address أو forwarded_ip_address. وهما يتوافقان مع الحقل في جدول system.quotas.
المعاملات queries, query_selects, query_inserts, errors, result_rows, result_bytes, read_rows, read_bytes, written_bytes, execution_time, failed_sequential_authentications, queries_per_normalized_hash تتوافق مع الحقول في جدول system.quotas_usage.
تتيح عبارة ON CLUSTER إنشاء quotas على cluster، راجع Distributed DDL.
أمثلة
قيِّد الحد الأقصى لعدد الاستعلامات للمستخدم الحالي إلى 123 استعلامًا ضمن قيد مدته 15 شهرًا:
CREATE QUOTA qA FOR INTERVAL 15 month MAX queries = 123 TO CURRENT_USER;
CREATE QUOTA qB FOR INTERVAL 30 minute MAX execution_time = 0.5, FOR INTERVAL 5 quarter MAX queries = 321, errors = 10 TO default;
CREATE QUOTA qC KEYED BY normalized_query_hash FOR INTERVAL 1 hour MAX queries = 100 TO default;
CREATE QUOTA qD FOR INTERVAL 1 hour MAX queries_per_normalized_hash = 50 TO default;
آخر تعديل في ٢٥ يونيو ٢٠٢٦
