The cache analytics feature can analyze backup files of ApsaraDB for Redis and find big keys in your instances. This feature allows you to view the information about an instance, such as the memory usage, distribution, and expiration time of keys. You can optimize your instances based on the analytic results. This feature helps you resolve issues such as insufficient memory and performance degradation that are caused by the skewed distribution of keys.

Prerequisites

In this example, an ApsaraDB for Redis instance of Community Edition or Enhanced Edition (Performance-enhanced instances) is used.

Procedure

  1. Log on to the ApsaraDB for Redis console.
  2. On the top of the page, select the region where the instance is deployed.
  3. On the Instance List page, click the Instance ID of the instance.
  4. In the left-side navigation pane, choose CloudDBA > Cache analysis.
    By default, the analytic results of the last day are displayed on the Cache analysis tab. You can specify another time range based on your requirements.
  5. On the Cache analysis tab, click Immediate Analysis.
    Cache analytics
  6. In the dialog box that appears, specify the node and analysis method.
    Specify the node and analysis method
    Parameter Description
    Select an analysis node Select the ID of the node on which you want to perform cache analytics.
    Note You can select an instance or a node. If you select an instance that contains more than eight nodes, the system analyzes only the top eight nodes with the highest memory usage.
    Analysis Method The method that you use to analyze the cache. Valid values: Use the previous backup file and Create a new backup and use the latest backup for analysis.
  7. Click OK.
    The system performs cache analytics and displays the analysis status. You can click Refresh to update the analysis status.
  8. Find the completed analysis task and click Details in the Actions column to view the details about the analytic results.
    Note If you select a cluster instance or a read/write splitting instance from the Select an analysis node drop-down list, you can view the information about related nodes and select a node in the Details section of the Details page.
    • Basic information: displays basic information about an instance such as the basic attributes and cache analytics method. Basic information
    • Related node: displays the memory usage and statistics about keys on each node of the instance. Result 1
    • Details: displays the details about an instance or a node, such as the memory usage, distribution of keys, memory usage and distribution of elements in keys, distribution of key expiration time, and ranking of big keys. Cache analytics details

FAQ

Q: Why do I fail to perform cache analytics?
Figure 1. Cache analytics failure
Cache analytics failure

A: Bloom filter-related API operations, such as BF.ADD, on existing instances of ApsaraDB for Redis 4.0 are only for internal use. In addition, newly purchased instances of ApsaraDB for Redis 4.0 and major versions later than 4.0 no longer support Bloom filter-related API operations. Therefore, if you call Bloom filter-related API operations, you fail to perform cache analytics and unknown errors may occur. We recommend that you change the instance to ApsaraDB for Redis Enhanced Edition (Tair) (Performance-enhanced instances) that supports the optimized Bloom filter.