1. 29 Oct, 2024 1 commit
    • Moti Cohen's avatar
      Add KEYSIZES section to INFO (#13592) · 2ec78d26
      Moti Cohen authored
      This PR adds a new section to the `INFO` command output, called
      `keysizes`. This section provides detailed statistics on the
      distribution of key sizes for each data type (strings, lists, sets,
      hashes and zsets) within the dataset. The distribution is tracked using
      a base-2 logarithmic histogram.
      
      # Motivation
      Currently, Redis lacks a built-in feature to track key sizes and item
      sizes per data type at a granular level. Understanding the distribution
      of key sizes is critical for monitoring memory usage and optimizing
      performance, particularly in large datasets. This enhancement will allow
      users to inspect the size distribution of keys directly from the `INFO`
      command, assisting with performance analysis and capacity planning.
      
      # Changes
      New Section in `INFO` Command: A new section called `keysizes` has been
      added to the `INFO` command output. This section reports a per-database,
      per-type histogram of key sizes. It provides insights into how many keys
      fall into specific size ranges (represented in powers of 2).
      
      **Example output:**
      ```
      127.0.0.1:6379> INFO keysizes
      # Keysizes
      db0_distrib_strings_sizes:1=19,2=655,512=100899,1K=31,2K=29,4K=23,8K=16,16K=3,32K=2
      db0_distrib_lists_items:1=5784492,32=3558,64=1047,128=676,256=533,512=218,4K=1,8K=42
      db0_distrib_sets_items:1=735564=50612,8=21462,64=1365,128=974,2K=292,4K=154,8K=89,
      db0_distrib_hashes_items:2=1,4=544,32=141169,64=207329,128=4349,256=136226,1K=1
      ```
      ## Future Use Cases:
      The key size distribution is collected per slot as well, laying the
      groundwork for future enhancements related to Redis Cluster.
      2ec78d26