29.12.22.13 The system_process_stats Table

Per-thread statistics of the MySQL server process. The first row is an aggregate for all threads in the process.

mysql> select * from performance_schema.system_process_stats limit 5\G
*************************** 1. row ***************************
         TIMESTAMP: 2026-10-01 10:07:58
               PID: 2505
      PROCESS_NAME: mysqld
               TID: 2505
       THREAD_NAME: mysqld
             STATE: S
          UTIME_MS: 170
          STIME_MS: 330
         CUTIME_MS: 0
         CSTIME_MS: 0
       NUM_THREADS: 42
       VSIZE_BYTES: 3110608896
         RSS_BYTES: 499580928
      RSSLIM_BYTES: 18446744073709551615
         PROCESSOR: 5
DELAYACCT_BLKIO_MS: 0
     GUEST_TIME_MS: 0
    CGUEST_TIME_MS: 0
        READ_BYTES: 85598208
       WRITE_BYTES: 352256
*************************** 2. row ***************************
         TIMESTAMP: 2026-10-01 10:07:58
               PID: 2505
      PROCESS_NAME: mysqld
               TID: 2508
       THREAD_NAME: ib_io_ibuf
             STATE: S
          UTIME_MS: 790
          STIME_MS: 1550
         CUTIME_MS: 0
         CSTIME_MS: 0
       NUM_THREADS: NULL
       VSIZE_BYTES: NULL
         RSS_BYTES: NULL
      RSSLIM_BYTES: NULL
         PROCESSOR: 2
DELAYACCT_BLKIO_MS: 0
     GUEST_TIME_MS: 0
    CGUEST_TIME_MS: 0
        READ_BYTES: 0
       WRITE_BYTES: 0
*************************** 3. row ***************************
         TIMESTAMP: 2026-10-01 10:07:58
               PID: 2505
      PROCESS_NAME: mysqld
               TID: 2509
       THREAD_NAME: ib_io_rd-1
             STATE: S
          UTIME_MS: 760
          STIME_MS: 1600
         CUTIME_MS: 0
         CSTIME_MS: 0
       NUM_THREADS: NULL
       VSIZE_BYTES: NULL
         RSS_BYTES: NULL
      RSSLIM_BYTES: NULL
         PROCESSOR: 2
DELAYACCT_BLKIO_MS: 0
     GUEST_TIME_MS: 0
    CGUEST_TIME_MS: 0
        READ_BYTES: 0
       WRITE_BYTES: 0
*************************** 4. row ***************************

The system_process_stats table has the following columns:

• TIMESTAMP: Time when the measurement was taken.

• PID: The process ID.

• PROCESS_NAME: The filename of the executable.

• TID: The thread ID.

• THREAD_NAME: Instrumented thread name.

• STATE: One of the following thread states:

  • R: Running.

  • S: Sleeping in an interruptible wait.

  • D: Waiting in uninterruptible disk sleep.

  • Z: Zombie.

  • T: Stopped on a signal or trace stopped.

  • W: Paging.

  • X: Dead.

  • K: Wakekill.

  • W: Waking.

  • P: Parked.

• UTIME_MS: Process time in user mode, in milliseconds.

• STIME_MS: Process time in kernel mode, in milliseconds.

• CUTIME_MS: Process children time in user mode, in milliseconds.

• CSTIME_MS: Process children time in kernel mode, in milliseconds.

• NUM_THREADS: Number of threads in this process.

• VSIZE_BYTES: Virtual memory size in bytes

• RSS_BYTES: Resident Set Size: number of bytes the process has in real memory

• RSSLIM_BYTES: Limit in bytes on the RSS of the process

• PROCESSOR: CPU number last executed on

• DELAYACCT_BLKIO_MS: Aggregated block I/O delays, in milliseconds.

• GUEST_TIME_MS: Guest time of the process, in milliseconds.

• CGUEST_TIME_MS: Guest time of the process's children, in milliseconds.

• READ_BYTES: Number of bytes that this process fetched from the storage layer.

• WRITE_BYTES: Number of bytes that this process sent to the storage layer.