# TrackerImpl config

**URL:** <https://forum.canton.network/t/trackerimpl-config/372>\
**Category:** App Development\
**Tags:** sandbox\
**Created:** [May 6, 2020, 2:49pm UTC](https://forum.canton.network/t/trackerimpl-config/372 "2020-05-06T14:49:38Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![shaynefletcher](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/shaynefletcher/32/567_2.png) [@shaynefletcher](https://forum.canton.network/u/shaynefletcher)\
**Post date:** [May 6, 2020, 2:49pm UTC](https://forum.canton.network/t/trackerimpl-config/372/1 "2020-05-06T14:49:38Z")

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I’m a newbie that got dropped into trying to quickly muster some support for questions coming out of a production upgrade.

The file `sandbox/src/main/scala/com/digitalasset/platform/apiserver/services/tracking/TrackerImpl.scala` defines an object `TrackerImpl`.

(1) What role does this object play?  
(2) It appears to host a couple of fixed size input queues where the size is determined by configuration constants:

```scala
 final case class Configuration(
      ledgerId: LedgerId,
      inputBufferSize: Int,
      maxCommandsInFlight: Int,
      limitMaxCommandsInFlight: Boolean,
      retentionPeriod: FiniteDuration,
      // TODO(RA): this should be updated dynamically from the ledger configuration
      maxDeduplicationTime: java.time.Duration,
  )

```

I presume this all relates to ledger configuration. Are these constants configurable from the ledger command line? How does one manipulate them?

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<div class="post-metadata">

**Author:** ![stefanobaghino-da](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/stefanobaghino-da/32/7057_2.png) [@stefanobaghino-da](https://forum.canton.network/u/stefanobaghino-da)\
**Post date:** [May 6, 2020, 3:05pm UTC](https://forum.canton.network/t/trackerimpl-config/372/2 "2020-05-06T15:05:42Z")

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`daml sandbox --help` probably puts it best. 😃

```haskell
--max-commands-in-flight <value>
The maximum number of unconfirmed commands in flight in CommandService.

```

The default should be 256.

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<div class="post-metadata">

**Author:** ![shaynefletcher](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/shaynefletcher/32/567_2.png) [@shaynefletcher](https://forum.canton.network/u/shaynefletcher)\
**Post date:** [May 6, 2020, 3:07pm UTC](https://forum.canton.network/t/trackerimpl-config/372/3 "2020-05-06T15:07:29Z")

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Yes, but in fact it is the `inputBufferSize: Int,` one I have an interest in. I did of course look at the help 😉

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<div class="post-metadata">

**Author:** ![stefanobaghino-da](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/stefanobaghino-da/32/7057_2.png) [@stefanobaghino-da](https://forum.canton.network/u/stefanobaghino-da)\
**Post date:** [May 6, 2020, 3:35pm UTC](https://forum.canton.network/t/trackerimpl-config/372/4 "2020-05-06T15:35:34Z")

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That is not configurable via the CLI.

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<div class="post-metadata">

**Author:** ![shaynefletcher](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/shaynefletcher/32/567_2.png) [@shaynefletcher](https://forum.canton.network/u/shaynefletcher)\
**Post date:** [May 6, 2020, 5:19pm UTC](https://forum.canton.network/t/trackerimpl-config/372/5 "2020-05-06T17:19:27Z")

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Rather suspected it wasn’t. Should it be? Perhaps it’s intimately related to other parameters from which it can thus be deduced in which case no I guess?

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<div class="post-metadata">

**Author:** ![stefanobaghino-da](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/stefanobaghino-da/32/7057_2.png) [@stefanobaghino-da](https://forum.canton.network/u/stefanobaghino-da)\
**Post date:** [May 6, 2020, 5:22pm UTC](https://forum.canton.network/t/trackerimpl-config/372/6 "2020-05-06T17:22:37Z")

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I agree it should be configurable. Perhaps if you have further points we can merge [this discussion](https://discuss.daml.com/t/tuning-commandconfiguration-settings/377) in this other thread where this point popped up. 🙂

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<div class="post-metadata">

**Author:** ![shaynefletcher](https://yyz2.discourse-cdn.com/flex034/user_avatar/forum.canton.network/shaynefletcher/32/567_2.png) [@shaynefletcher](https://forum.canton.network/u/shaynefletcher)\
**Post date:** [May 6, 2020, 5:23pm UTC](https://forum.canton.network/t/trackerimpl-config/372/7 "2020-05-06T17:23:39Z")

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I’m satisfied and happy for this thread to be merged. Thank-you!