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Health Checks

Use Health Checks to review the MySQL system, storage-engine, memory, query, and log metrics that Releem evaluates. Review a check together with its current value and recent workload before deciding whether further investigation or a configuration change is needed.

Releem groups these metrics into four blocks: System, MyISAM/InnoDB, Memory, and Queries/Logs. A check is a diagnostic signal; it does not by itself identify the cause of a problem or guarantee a performance outcome.

Releem Health Checks block

System Block​

The System block shows essential system-level metrics for reviewing the overall state of your server.

  • CPU Utilization: Measures the percentage of CPU capacity being used.
  • Memory Utilization: Monitors the percentage of memory usage on the server.
  • Disk Space Usage: Tracks the amount of disk space being used and helps identify potential storage issues.
  • Database Connection Utilization: Monitors the percentage of connections used out of the total available connections.

MyISAM/InnoDB Block​

The MyISAM/InnoDB block focuses on specific storage engines and their related metrics.

  • MyISAM Cache Hit Rate: Measures the efficiency of the MyISAM key cache.
  • MyISAM Key Write Ratio: Monitors the ratio of key writes to key write requests for MyISAM tables.
  • InnoDB Cache Hit Rate: Assesses the effectiveness of the InnoDB buffer pool.
  • InnoDB Log File Size: Monitors the size of the InnoDB log files as an input to performance review.

Memory Block​

The Memory block checks metrics related to memory usage and allocation.

  • Thread Cache Hit Rate: Evaluates the effectiveness of the thread cache.
  • Thread Cache Ratio: Monitors the ratio of threads created to connections.
  • Table Cache Hit Rate: Measures the efficiency of the table cache.

Queries/Logs Block​

The Queries/Logs block examines metrics associated with queries and logs.

  • Sort Merge Passes Ratio: Measures the ratio of merge passes to sorts performed.
  • Temporary Disk Data: Monitors the amount of temporary data written to disk during query execution.
  • QCache Fragmentation: Tracks the fragmentation level of the query cache.
  • Flushing Logs: Tracks the frequency of log flushing, which can impact server performance.

Use these metrics to decide where to investigate further. Review a check with other server and workload evidence before acting on a Releem recommendation. A Health Check does not by itself prove the cause of a problem or guarantee that a change will improve performance.