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Error message

Configuration contains {actual} histogram leaves, which exceeds the maximum of {max}
Example: Configuration contains 78 histogram leaves, which exceeds the maximum of 64

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When this error occurs

The platform caps the total number of histogram-enabled primitive columns at 64 per configuration. This limit applies across both the dataset and Rosetta Stone namespaces combined. Every primitive leaf (string, integer, float, boolean, timestamp) that resolves to having the histogram stat enabled counts toward this limit. Object and array columns themselves do not count — only their primitive children do. This error is raised before saving the configuration, so no resources are wasted on an overly broad histogram setup.

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Common causes

  1. Broad defaults with histogram enabled — if defaults include histogram and the dataset has many columns, every compatible column gets a histogram automatically.
  2. Large nested objects — an object with many primitive properties, each inheriting histogram from defaults or scope, can quickly exhaust the limit.
  3. Both namespaces enabled — histograms on dataset columns plus Rosetta Stone attributes add up.

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Example: request that triggers this error

Given a dataset with 50 primitive columns and 20 Rosetta Stone attributes (all primitive): 
{
  "defaults": {
    "enabled_stats": ["value_count", "null_value_count", "histogram"]
  },
  "refresh": { "trigger": "manual" }
}
This enables histogram on all 70 primitive leaves (50 dataset + 20 Rosetta Stone), exceeding the limit of 64.

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How to fix

Reduce the number of histogram-enabled leaves below 64. Several strategies:

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Option A: Remove histogram from defaults, enable per-field

Move histogram out of defaults and enable it only on the fields that matter: 
{
  "defaults": {
    "enabled_stats": ["value_count", "null_value_count"]
  },
  "refresh": { "trigger": "manual" },
  "dataset": {
    "fields": [
      {
        "field_name": "price",
        "enabled_stats": ["value_count", "null_value_count", "histogram"]
      },
      {
        "field_name": "age",
        "enabled_stats": ["value_count", "null_value_count", "histogram"]
      }
    ]
  }
}

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Option B: Keep histogram in defaults, disable for one namespace

If you want histograms on dataset columns but not Rosetta Stone attributes: 
{
  "defaults": {
    "enabled_stats": ["value_count", "null_value_count", "histogram"]
  },
  "refresh": { "trigger": "manual" },
  "rosetta_stone": {
    "scope": {
      "enabled_stats": ["value_count", "null_value_count"]
    }
  }
}
The Rosetta Stone scope replaces the inherited stat set with one that excludes histogram.

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Option C: Disable histogram on specific high-cardinality fields

Override individual fields to drop histogram while keeping defaults broad: 
{
  "defaults": {
    "enabled_stats": ["value_count", "null_value_count", "histogram"]
  },
  "refresh": { "trigger": "manual" },
  "dataset": {
    "fields": [
      {
        "field_name": "raw_payload",
        "enabled_stats": ["value_count", "null_value_count"]
      },
      {
        "field_name": "metadata",
        "self": {
          "enabled_stats": ["null_value_count"]
        }
      }
    ]
  }
}
Fields listed with enabled_stats that exclude histogram no longer count toward the limit. Unlisted fields still inherit from defaults.

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Counting rules

  • Only primitive types count: StringType, LongType, DoubleType, BooleanType, TimestampTzType
  • Array items are excluded from the count (they are filtered at execution time)
  • Object and array columns themselves do not count — only their primitive children
  • The count spans both the dataset and rosetta_stone namespaces