This topic describes the limits of the alerting feature in Simple Log Service.
Alerting (New)
Category | Limit | Description |
Alerting and monitoring | Maximum number of alert rules | Each project supports a maximum of 100 alert rules. If you require a higher usage quota, submit a ticket. A single Project can be scaled out to a maximum of 200. |
General limits on query and analysis operations | For more information, see Query and analysis. | |
Concurrency limits on query and analysis operations | If you run many query and analysis operations concurrently in a project, such as using an SDK, and have many alert rules, the number of concurrent queries may exceed the project limit. This can cause monitoring to fail. When you create an alert rule, set Dedicated SQL to Automatic to support higher concurrency. When you use Dedicated SQL, make sure that the destination project has enough Dedicated SQL CUs. To create an alert rule, see Create an alert rule. To enable Dedicated SQL, see High-performance and high-accuracy query and analysis (Dedicated SQL). | |
Query and analysis syntax limits | Only query statements, analytic statements that use SQL syntax, and statements that use both SQL and Prometheus Query Language (PromQL) syntax are supported. Phrase query statements and query and analysis statements that use Scan mode are not supported. Note You can create alerts that use phrase query statements or query and analysis statements in Scan mode (Structured Process Language (SPL) syntax). However, these alerts may fail or produce unexpected results at runtime. | |
Single query and analysis result |
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Number of combined query and analysis operations | 1 to 3. | |
Field value length | If a field value exceeds 1,024 characters, only the first 1,024 characters are used for analysis. | |
Time range for query and analysis | The time span for each query and analysis statement cannot exceed 24 hours. | |
Resource data update latency | Resource data updates can take up to 15 minutes to take effect. | |
Alert management | Alert policy change delay | The minimum change delay is 15 seconds. Even if you set a smaller value, checks are performed at 15-second intervals. |
Policy matching conditions | In configurations such as alert policies and action policies, you can use project names, alert rule IDs, alert names, severity levels, and short tags or annotations as conditions.
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Number of transactions | A maximum of 1,000 transactions are retained for 30 days. If this limit is exceeded, the oldest transactional data is automatically overwritten. | |
Transaction comments | You can add a maximum of 10 comments to each transaction. If this limit is exceeded, older comments are automatically overwritten. | |
Policy configuration update latency | Updates to alert-related policy configurations, such as alert policies, action policies, content templates, users, user groups, and on-call groups, typically take effect within approximately 1 minute. | |
Notification management | Notification channels | The limits for each notification channel are listed below. If you exceed these limits, you may not receive alert notifications. If you do not receive an alert notification, you can view related errors in the Global Alert Troubleshooting Center. For more information, see Global Alert Troubleshooting Center.
For more information, see Notification channels. |
Notification content | Each notification channel has a content length limit. To prevent delivery failures, the system may truncate oversized content. However, content truncation does not guarantee content integrity or successful delivery. The success of the delivery depends on the truncated content and the capabilities of the notification channel. For example, a notification may fail if the truncated content results in invalid Markdown or HTML. For plain text content, such as text messages and voice calls, truncation does not typically cause delivery failures. To prevent delivery failures due to oversized content, configure content templates according to the limits of each notification channel. The limits are as follows (a Chinese character, an English letter, a digit, or a punctuation mark is counted as one character): Note If a field value exceeds 1,024 characters, only the first 1,024 characters are used.
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Content template configuration | An incorrect content template configuration can cause template rendering to fail and return an error message. If you receive an alert notification that contains an error message such as | |
Content template variables | The content length is limited to 2 KB. Any content that exceeds this limit is truncated. |
Alerting (Old)
| Limit | Description |
| Combined Query | You can associate 1 to 3 queries. |
| String | If a log field is longer than 1,024 characters, Simple Log Service truncates the field to the first 1,024 characters for calculation. |
| Conditional expression | The following limits apply to conditional expressions:
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| Query interval | The time span for each query statement cannot exceed 24 hours. |
| Voice call alert | If a voice call is not answered, it is not redialed. A text message notification is sent instead. A charge is incurred for each voice call attempt, regardless of whether it is answered. The fallback text message does not incur extra fees. |