29.12.22.6 The health_system_memory Table

System memory status information.

mysql> select * from performance_schema.health_system_memory\G
*************************** 1. row ***************************
      TIMESTAMP: 2026-09-30 10:10:34
   TOTAL_MEMORY: 8022503424
      AVAILABLE: 6198218752
    USE_PERCENT: 22.74
    MEMORY_FREE: 5191847936
MEMORY_FS_CACHE: 1232797696
     SWAP_TOTAL: 4236242944
      SWAP_FREE: 4236242944
*************************** 2. row ***************************
      TIMESTAMP: 2026-09-30 10:11:34
   TOTAL_MEMORY: 8022503424
      AVAILABLE: 4651024384
    USE_PERCENT: 42.03
    MEMORY_FREE: 2669998080
MEMORY_FS_CACHE: 2169552896
     SWAP_TOTAL: 4236242944
      SWAP_FREE: 4236242944
*************************** 3. row ***************************
      TIMESTAMP: 2026-09-30 10:12:34
   TOTAL_MEMORY: 8022503424
      AVAILABLE: 3765616640
    USE_PERCENT: 53.06
    MEMORY_FREE: 1466445824
MEMORY_FS_CACHE: 2514419712
     SWAP_TOTAL: 4236242944
      SWAP_FREE: 4236242944
*************************** 4. row ***************************
....

The health_system_memory table has the following columns:

• TIMESTAMP: The time the data sample in this row was collected.

• TOTAL_MEMORY: The total amount of memory for the system, in bytes.

• AVAILABLE: Estimated memory available for starting new applications without swapping, in bytes.

• USE_PERCENT: The percentage of memory in use. Calculated as (TOTAL_MEMORY-AVAILABLE)/TOTAL_MEMORY * 100.

• MEMORY_FREE: The amount of unused memory.

• MEMORY_FS_CACHE: Filesystem page cache.

• SWAP_TOTAL: Total amount of physical swap memory.

• SWAP_FREE: Total amount of swap memory free. Memory which has been evicted from RAM and is temporarily on disk.