Query object storage

Altertable can query data that already lives in Amazon S3, Cloudflare R2, Google Cloud Storage, or another S3-compatible bucket. Map the files once, then use the same SQL engine and query interfaces you use for Altertable catalogs.

Object storage queries run in place. Altertable reads mapped files from the connected bucket.

What you can query

Query mapped tables

After you map object storage, query the exposed tables with fully qualified names:

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SELECT
  event_name,
  count(*) AS event_count
FROM bucket_exports.main.events
WHERE event_date >= DATE '2026-01-01'
GROUP BY event_name
ORDER BY event_count DESC;

Mapped object-storage tables can be joined with Altertable-managed catalogs and other external catalogs:

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SELECT
  customers.segment,
  count(*) AS events
FROM bucket_exports.main.events
JOIN analytics.main.customers
  ON events.customer_id = customers.customer_id
GROUP BY customers.segment;

Query from any Altertable interface

Use object-storage tables from:

• SQL explorer for interactive analysis.
• HTTP API for applications and services.
• DuckDB for local analysis and file joins.
• Postgres adapter and Arrow Flight SQL adapter for BI tools.
• MCP tools and Ask Agent for agentic exploration.

Query performance

For large object-storage datasets, prefer columnar formats such as Parquet or Iceberg, keep partitions predictable, and filter on partition columns when possible. Altertable can query CSV and JSON files, but columnar formats usually scan less data and return results faster.