Summarizing indexes in Amazon OpenSearch Service with index rollups

Index rollups in Amazon OpenSearch Service let you reduce storage costs by periodically rolling up old data into summarized indexes.

You pick the fields that interest you and use an index rollup to create a new index with only those fields aggregated into coarser time buckets. You can store months or years of historical data at a fraction of the cost with the same query performance.

Index rollups requires OpenSearch or Elasticsearch 7.9 or later.

Creating an index rollup job

To get started, choose Index Management in OpenSearch Dashboards. Select Rollup Jobs and choose Create rollup job.

Step 1: Set up indexes

Set up the source and target indexes. The source index is the one that you want to roll up. The target index is where the index rollup results are saved.

After you create an index rollup job, you can’t change your index selections.

Step 2: Define aggregations and metrics

Select the attributes with the aggregations (terms and histograms) and metrics (avg, sum, max, min, and value count) that you want to roll up. Make sure you don’t add a lot of highly granular attributes, because you won’t save much space.

Step 3: Specify schedules

Specify a schedule to roll up your indexes as it’s being ingested. The index rollup job is enabled by default.

Step 4: Review and create

Review your configuration and select Create.

Step 5: Search the target index

You can use the standard _search API to search the target index. You can’t access the internal structure of the data in the target index because the plugin automatically rewrites the query in the background to suit the target index. This is to make sure you can use the same query for the source and target index.

To query the target index, set size to 0:

GET target_index/_search
{
  "size": 0,
  "query": {
    "match_all": {}
  },
  "aggs": {
    "avg_cpu": {
      "avg": {
        "field": "cpu_usage"
      }
    }
  }
}