Storage Policy

note

Storage policies are available in QuestDB Enterprise only.

A storage policy automates the lifecycle of table partitions. It defines when partitions are converted to Parquet and when local copies are dropped. Converting a partition to Parquet removes its native files and serves reads directly from the Parquet file. This replaces the need for manual partition management or external scheduling.

info

Storage policies currently operate locally only. Parquet files are not automatically uploaded to object storage, so the TO REMOTE and DROP REMOTE clauses are reserved syntax — they are rejected at SQL parse time with 'TO REMOTE' is not supported yet and 'DROP REMOTE' is not supported yet. Accordingly, the to_remote and drop_remote columns in the storage_policies view are always blank in the current release; they are kept for forward compatibility. Object storage integration will be added in a future release.

Requirements

Storage policies require:

• A designated timestamp column
• Partitioning enabled
• QuestDB Enterprise

How it works

A storage policy consists of up to four TTL settings. Each setting controls a stage in the partition lifecycle:

Setting	Description
TO PARQUET	Convert the partition from native binary format to Parquet. The native files are removed and reads are served from the Parquet file
TO REMOTE	Reserved. Will upload the Parquet file to object storage when remote upload is supported
DROP LOCAL	Remove all local data (native or Parquet)
DROP REMOTE	Reserved. Will remove the Parquet file from object storage when remote upload is supported

All settings are optional. Use only the ones relevant to your use case. All TTL values must be positive; 0 is rejected.

Partition lifecycle

As time passes, each partition progresses through the stages defined by the policy:

                       TO PARQUET                 DROP LOCAL
   [Native] ───────────────┬──────────────────────────┬───────
                           │                          │
                           ▼                          ▼
                    Parquet only (local)         Data removed

TTL evaluation

Storage policy TTLs follow the same evaluation rules as TTL. A partition becomes eligible for a lifecycle action when its entire time range falls outside the TTL window:

eligible when: partition_end_time < reference_time - TTL

This rule is applied independently for each stage's TTL. A partition can be eligible for TO PARQUET long before it is eligible for DROP LOCAL (or, one day, the reserved TO REMOTE and DROP REMOTE stages). Each stage uses its own TTL in the formula above; the stages share only the reference time and the ordering constraints.

The reference time is min(wall_clock_time, latest_timestamp) by default — the same formula used by TTL. The cairo.ttl.use.wall.clock setting applies to storage policies as well: setting it to false removes the wall-clock cap for both TTL and storage policy evaluation. See TTL § Reference time for the rationale and the data-loss hazard of disabling the cap.

QuestDB checks storage policies periodically (every 15 minutes by default) and processes eligible partitions automatically.

Storage policy vs TTL

Storage policies replace TTL in QuestDB Enterprise. If you are already familiar with TTL, this comparison is the fastest way in:

	TTL	Storage Policy
Availability	Open source	Enterprise only
Action	Drops partitions entirely	Graduated lifecycle (convert, then drop)
Parquet conversion	No	Yes (automatic local conversion)
Granularity	Single retention window	Up to four independent TTL stages

In QuestDB Enterprise, CREATE TABLE ... TTL and ALTER TABLE SET TTL are deprecated. Use storage policies instead:

-- Instead of:
-- ALTER TABLE trades SET TTL 30 DAYS;

-- Use:
ALTER TABLE trades SET STORAGE POLICY(DROP LOCAL 30d);

note

If a table already has a TTL set, you must clear it with ALTER TABLE SET TTL 0 before setting a storage policy. SET TTL 0 is the only SET TTL value Enterprise accepts; any non-zero value is rejected with TTL settings are deprecated, please, create a storage policy instead.

Setting a storage policy

At table creation

CREATE TABLE trades (
    ts TIMESTAMP,
    symbol SYMBOL,
    price DOUBLE
) TIMESTAMP(ts) PARTITION BY DAY
    STORAGE POLICY(TO PARQUET 3d, DROP LOCAL 1M)
    WAL;

On existing tables

ALTER TABLE trades SET STORAGE POLICY(
    TO PARQUET 3 DAYS,
    DROP LOCAL 1 MONTH
);

Only the specified settings are changed. Omitted settings remain unchanged.

For full syntax details, see ALTER TABLE SET STORAGE POLICY.

TTL duration format

Storage policy TTLs accept the same duration formats as TTL:

Unit	Long form	Short form
Hours	1 HOUR / 2 HOURS	1h
Days	1 DAY / 3 DAYS	1d / 3d
Weeks	1 WEEK / 2 WEEKS	1W / 2W
Months	1 MONTH / 6 MONTHS	1M / 6M
Years	1 YEAR / 2 YEARS	1Y / 2Y

Ordering constraint

The stages form a partial order, not a single chain. A drop stage may not fire before the write stage it depends on:

TO PARQUET <= DROP LOCAL
TO REMOTE  <= DROP LOCAL <= DROP REMOTE

TO PARQUET and TO REMOTE are independent — neither has to precede the other. If TO REMOTE fires before TO PARQUET, both the native and Parquet copies are written locally and reads continue to be served from the native format until TO PARQUET removes the native files. All TTL values must be positive — 0 is rejected.

Disabling and enabling

Temporarily suspend a storage policy without removing it:

ALTER TABLE trades DISABLE STORAGE POLICY;

Re-enable it later:

ALTER TABLE trades ENABLE STORAGE POLICY;

Both ENABLE and DISABLE require a policy to exist on the table; the statement returns an error otherwise.

Removing a storage policy

To permanently remove a storage policy from a table:

ALTER TABLE trades DROP STORAGE POLICY;

Checking storage policies

Query the storage_policies system view to see all active policies:

SELECT * FROM storage_policies;

table_dir_name	to_parquet	to_remote	drop_local	drop_remote	status	last_updated
trades~12	72h		1m		A	2025-01-15T10:30:00.000000Z

• TTL values are rendered in just two units: h for hours and m for months. Hour-, day-, and week-based durations are normalized to hours when stored, so a 3 DAYS TTL appears as 72h and 1 WEEK appears as 168h. Month-based durations keep the lowercase m suffix — 1m in this view means one month, not one minute; QuestDB's duration shorthand has no unit for minutes
• Status A means active; D means disabled (see Disabling and enabling)
• Unset stages appear blank. to_remote and drop_remote are always blank in the current release because TO REMOTE and DROP REMOTE are rejected at SQL parse time with 'TO REMOTE' is not supported yet and 'DROP REMOTE' is not supported yet; the columns are kept for forward compatibility

For the full column reference and types, see storage_policies.

Replication

Storage policy definitions are persisted in WAL-backed system tables, so the policy itself is replicated to every instance in the cluster. Enforcement runs independently on each instance — Parquet files are produced locally and are not replicated.

This means the primary and its replicas can temporarily disagree on which partitions have been converted to Parquet or dropped, depending on when each node's storage policy check interval last fired. The state converges as each instance processes its own queue. See Replication overview for details.

Configuration

Storage policy behavior can be tuned in server.conf. Time-based properties accept values with unit suffixes (e.g., 15m, 30s, 1h) or raw microsecond values:

Property	Default	Description
storage.policy.check.interval	15m (15 min)	How often QuestDB scans for partitions to process
storage.policy.retry.interval	1m (1 min)	Retry interval for failed tasks
storage.policy.max.reschedule.count	20	Maximum retries before abandoning a task
storage.policy.writer.wait.timeout	30s (30 sec)	Timeout for acquiring the table writer
storage.policy.worker.count	2	Number of storage policy worker threads (0 disables the feature)
storage.policy.worker.affinity	-1 (no affinity)	CPU affinity for each worker thread (comma-separated list)
storage.policy.worker.sleep.timeout	100ms	Sleep duration when worker has no tasks

Permissions

Storage policy operations require specific permissions in QuestDB Enterprise:

Operation	Required permission
SET STORAGE POLICY	SET STORAGE POLICY
DROP STORAGE POLICY	REMOVE STORAGE POLICY
ENABLE STORAGE POLICY	ENABLE STORAGE POLICY
DISABLE STORAGE POLICY	DISABLE STORAGE POLICY

Grant permissions using standard RBAC syntax:

GRANT SET STORAGE POLICY ON trades TO analyst;
GRANT REMOVE STORAGE POLICY ON trades TO admin;

End-to-end example

A complete lifecycle on a single table, from creation through verification, modification, inspection of the generated DDL, temporary suspension, and permanent removal:

1. Create the table with a storage policy

CREATE TABLE trades (
    ts TIMESTAMP,
    symbol SYMBOL,
    price DOUBLE
) TIMESTAMP(ts) PARTITION BY DAY
    STORAGE POLICY(TO PARQUET 3d, DROP LOCAL 1M)
    WAL;

2. Verify via the system view

SELECT table_dir_name, to_parquet, drop_local, status
FROM storage_policies
WHERE table_dir_name LIKE 'trades%';

table_dir_name	to_parquet	drop_local	status
trades~12	72h	1m	A

3. Modify one stage (others remain unchanged)

ALTER TABLE trades SET STORAGE POLICY(TO PARQUET 1d);

4. Inspect the current DDL

SHOW CREATE TABLE trades;

CREATE TABLE 'trades' (
    ts TIMESTAMP,
    symbol SYMBOL CAPACITY 256 CACHE,
    price DOUBLE
) timestamp(ts) PARTITION BY DAY
STORAGE POLICY(TO PARQUET 1 DAY) WAL;

5. Temporarily suspend the policy (e.g. during a backfill)

ALTER TABLE trades DISABLE STORAGE POLICY;
-- status in storage_policies changes to 'D'

6. Re-enable and, later, drop it for good

ALTER TABLE trades ENABLE STORAGE POLICY;
ALTER TABLE trades DROP STORAGE POLICY;
-- row disappears from storage_policies

Guidelines

Use case	Suggested policy	Rationale
Real-time metrics	TO PARQUET 1d, DROP LOCAL 30d	Keep recent data fast, drop old data automatically
Trading data	TO PARQUET 7d	Keep Parquet locally for long-term queries
IoT telemetry	TO PARQUET 1d, DROP LOCAL 90d	High volume, convert early to save disk before dropping the data
Aggregated views	TO PARQUET 30d	Low volume, keep locally in Parquet

Tips:

• Start with TO PARQUET to reduce local disk usage while keeping data queryable in Parquet format
• Use DROP LOCAL with care as it permanently removes data from the local disk
• TTL values should be significantly larger than the partition interval