30.4.5.17 The ps_thread_trx_info() Function

Returns a JSON object containing information about a given thread. The information includes the current transaction, and the statements it has already executed, derived from the Performance Schema events_transactions_current and events_statements_history tables. (The consumers for those tables must be enabled to obtain full data in the JSON object.)

If the output exceeds the truncation length (65535 by default), a JSON error object is returned, such as:

{ "error": "Trx info truncated: Row 6 was cut by GROUP_CONCAT()" }

Similar error objects are returned for other warnings and exceptions raised during function execution.

Parameters

• in_thread_id BIGINT UNSIGNED: The thread ID for which to return transaction information. The value should match the THREAD_ID column from some Performance Schema threads table row.

Configuration Options

ps_thread_trx_info() operation can be modified using the following configuration options or their corresponding user-defined variables (see Section 30.4.2.1, “The sys_config Table”):

• ps_thread_trx_info.max_length, @sys.ps_thread_trx_info.max_length

  The maximum length of the output. The default is 65535.

Return Value

A LONGTEXT value.

Example

mysql> SELECT sys.ps_thread_trx_info(48)\G
*************************** 1. row ***************************
sys.ps_thread_trx_info(48): [
  {
    "time": "790.70 us",
    "state": "COMMITTED",
    "mode": "READ WRITE",
    "autocommitted": "NO",
    "gtid": "AUTOMATIC",
    "isolation": "REPEATABLE READ",
    "statements_executed": [
      {
        "sql_text": "INSERT INTO info VALUES (1, \'foo\')",
        "time": "471.02 us",
        "schema": "trx",
        "rows_examined": 0,
        "rows_affected": 1,
        "rows_sent": 0,
        "tmp_tables": 0,
        "tmp_disk_tables": 0,
        "sort_rows": 0,
        "sort_merge_passes": 0
      },
      {
        "sql_text": "COMMIT",
        "time": "254.42 us",
        "schema": "trx",
        "rows_examined": 0,
        "rows_affected": 0,
        "rows_sent": 0,
        "tmp_tables": 0,
        "tmp_disk_tables": 0,
        "sort_rows": 0,
        "sort_merge_passes": 0
      }
    ]
  },
  {
    "time": "426.20 us",
    "state": "COMMITTED",
    "mode": "READ WRITE",
    "autocommitted": "NO",
    "gtid": "AUTOMATIC",
    "isolation": "REPEATABLE READ",
    "statements_executed": [
      {
        "sql_text": "INSERT INTO info VALUES (2, \'bar\')",
        "time": "107.33 us",
        "schema": "trx",
        "rows_examined": 0,
        "rows_affected": 1,
        "rows_sent": 0,
        "tmp_tables": 0,
        "tmp_disk_tables": 0,
        "sort_rows": 0,
        "sort_merge_passes": 0
      },
      {
        "sql_text": "COMMIT",
        "time": "213.23 us",
        "schema": "trx",
        "rows_examined": 0,
        "rows_affected": 0,
        "rows_sent": 0,
        "tmp_tables": 0,
        "tmp_disk_tables": 0,
        "sort_rows": 0,
        "sort_merge_passes": 0
      }
    ]
  }
]