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Tracking System and User Time Spent on Transactions

You can track the amount of System or User time spent on transactions:

  • System time is the time that is spent for system activities: time spent while acquiring locks, "get/put" operations, preparing, committing, etc.

  • User time is the time that is spent for user activities (calculations, etc.) that are run on a client node as part of a transaction. User time is the total time minus the system time.

You can configure logging to include information about transactions that exceed a threshold execution timeout. You can also configure logging to include a random sampling of some percentage of all completed transactions. These thresholds are set via Related JMX Parameters and JVM Options.

The log records for long-running transactions look like this:

[2019-08-09 13:39:49,130][WARN ][sys-stripe-1-#101%client%]
[root] Long transaction time dump [startTime=13:39:47.970, totalTime=1160, systemTime=157,
userTime=1003, cacheOperationsTime=141, prepareTime=15, commitTime=0, tx=GridNearTxLocal [...]]

Log records with a random sampling of completed transactions look like this:

[2019-08-09 13:39:54,079][INFO ][sys-stripe-2-#102%client%]
[root] Transaction time dump [startTime=13:39:54.063, totalTime=15, systemTime=6,
userTime=9, cacheOperationsTime=2, prepareTime=3, commitTime=0, tx=GridNearTxLocal [...]]

Also, Ignite logging can be configured so that some transactions can be skipped in order to not overflow the log, through a process called Log Throttling. In those cases, information about log throttling looks like this:

[2019-08-09 13:39:55,109][INFO ][sys-stripe-0-#100%client%][root]
Transaction time dumps skipped because of log throttling: 2

JMX parameters and JVM options used to control the system and user time tracking behavior:

Long-Running Query Threshold

JVM option: IGNITE_LONG_TRANSACTION_TIME_DUMP_THRESHOLD

JMX parameter: TransactionsMXBean.longTransactionTimeDumpThreshold

Threshold timeout in milliseconds for long transactions. If a transaction exceeds it, it will be dumped in the log with information about how much time it spent in system time and user time. Default value is 0. No information about system/user time of long transactions is dumped to the log if this parameter is not set.

Sampling Percentage

JVM option: IGNITE_TRANSACTION_TIME_DUMP_SAMPLES_COEFFICIENT

JMX parameter: TransactionsMXBean.transactionTimeDumpSamplesCoefficient

This is the coefficient for samples of completed transactions that will be dumped to the log. Must be a float value between 0.0 and 1.0 inclusive. Default value is 0.0.

JVM option: IGNITE_TRANSACTION_TIME_DUMP_SAMPLES_PER_SECOND_LIMIT

JMX parameter: TransactionsMXBean.transactionTimeDumpSamplesPerSecondLimit

The limit of samples of completed transactions that will be dumped to the log per second, if IGNITE_TRANSACTION_TIME_DUMP_SAMPLES_COEFFICIENT is above 0.0. Must be an integer value greater than 0. Default value is 5.

Log throttling and information about skipped transactions are tied to the limit set by TransactionsMXBean.transactionTimeDumpSamplesPerSecondLimit. For example, say you have 100 transactions per second, and you want to sample just a part of them, maybe 50%. So you set the percentage to 0.5 via TransactionsMXBean.transactionTimeDumpSamplesCoefficient. Now 50 transactions per second will be sampled in the log.

Now suppose you realize you don’t need to see that many, so you set the limit to 15 via TransactionsMXBean.transactionTimeDumpSamplesPerSecondLimit. Now the log will show a maximum of 15 transactions per second, and also that 35 were skipped because of log throttling.

New metrics used to monitor system and user time for a single node:

  • TransactionMetricsMxBean.totalNodeSystemTime: Total transactions system time on node.

  • TransactionMetricsMxBean.totalNodeUserTime: Total transactions user time on node.

  • TransactionMetricsMxBean.nodeSystemTimeHistogram: Transactions system times on node represented via histogram.

  • TransactionMetricsMxBean.nodeUserTimeHistogram: Transactions user times on node represented via histogram.

Histogram metrics are exported as JSON strings, and typically look like this:

{
  "bounds":
    [1,2,4,8,16,25,50,75,100,250,500,750,1000,3000,5000,10000,25000,60000],
  "values":
    [
      {"fromExclusive":0,"toInclusive":1,"value":0},
      {"fromExclusive":1,"toInclusive":2,"value":0},
      {"fromExclusive":2,"toInclusive":4,"value":0},
      {"fromExclusive":4,"toInclusive":8,"value":0},
      {"fromExclusive":8,"toInclusive":16,"value":0},
      {"fromExclusive":16,"toInclusive":25,"value":0},
      {"fromExclusive":25,"toInclusive":50,"value":0},
      {"fromExclusive":50,"toInclusive":75,"value":2},
      {"fromExclusive":75,"toInclusive":100,"value":0},
      {"fromExclusive":100,"toInclusive":250,"value":0},
      {"fromExclusive":250,"toInclusive":500,"value":0},
      {"fromExclusive":500,"toInclusive":750,"value":0},
      {"fromExclusive":750,"toInclusive":1000,"value":0},
      {"fromExclusive":1000,"toInclusive":3000,"value":1},
      {"fromExclusive":3000,"toInclusive":5000,"value":0},
      {"fromExclusive":5000,"toInclusive":10000,"value":0},
      {"fromExclusive":10000,"toInclusive":25000,"value":0},
      {"fromExclusive":25000,"toInclusive":60000,"value":0},
      {"fromExclusive":60000,"value":0}
    ]
}

For information about JSON histograms, see Working with Histograms.

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Last updated on Apr 02, 2026