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. TO PARQUET and DROP LOCAL are the enforced stages. TO REMOTE is accepted and stored but not yet enforced, so setting it has no effect for now: no upload to object storage happens yet. DROP REMOTE is not yet supported and is rejected at SQL parse time with 'DROP REMOTE' is not supported yet. In the storage_policies view the drop_remote column is therefore always 0h, and to_remote reads 0h unless you set a TO REMOTE value (which is stored but has no effect yet). 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`	Accepted and stored but not yet enforced; no upload happens yet. Reserved for future object storage upload
`DROP LOCAL`	Remove all local data (native or Parquet)
`DROP REMOTE`	Not yet supported. Rejected at parse time with `'DROP REMOTE' is not supported yet`. Reserved for future object storage removal

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, once remote upload is enforced, the 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 5 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, use storage policies instead of TTL. On a regular table, ALTER TABLE SET TTL with a non-zero value is rejected, while CREATE TABLE ... TTL is accepted only for backward compatibility and is translated into a STORAGE POLICY(DROP LOCAL ...):

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

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

note

A table can carry a TTL only if it was created in QuestDB Open Source and later upgraded to Enterprise. Clear that legacy TTL with ALTER TABLE SET TTL 0 before setting a storage policy; otherwise SET STORAGE POLICY is rejected with Cannot set storage policy, please, remove TTL settings. On Enterprise tables SET TTL 0 is the only accepted SET TTL value; any non-zero value is rejected with TTL is not supported on Enterprise tables; use 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
);

SET STORAGE POLICY replaces the policy in full: every stage you omit is cleared, not preserved. To keep a stage, restate it in the same statement.

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. Once remote upload is enforced, a TO REMOTE that runs before TO PARQUET would keep both the native and Parquet copies on local disk, with reads 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 policies and their status:

SELECT * FROM storage_policies;

table_dir_name	to_parquet	to_remote	drop_local	drop_remote	status	last_updated
trades~12	72h	0h	1m	0h	A	2025-01-15T10:30:00.000000Z

TTL values are rendered in two units: h for hours and m for months. Hour-, day-, and week-based durations are stored as hours, so a 3 DAYS TTL appears as 72h and 1 WEEK as 168h. Month- and year-based durations are stored as months, so 1 MONTH appears as 1m and 1 YEAR as 12m. In this view m means months, not minutes; QuestDB's duration shorthand has no unit for minutes
Status A means active; D means disabled (see Disabling and enabling)
An unset stage renders as 0h, not blank. Because DROP REMOTE is rejected at parse time, drop_remote is always 0h; to_remote reads 0h unless a TO REMOTE value is set (stored, but not yet enforced)

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., 5m, 1h, 100ms) or raw microsecond values:

Property	Default	Description
`storage.policy.check.interval`	`5m` (5 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.worker.count`	`4`	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

See Storage policy configuration for the complete list, including the remaining worker-pool tuning properties.

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. Replace the policy (omitted stages are cleared)

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;

The DROP LOCAL 1 MONTH stage from step 1 is gone: step 3 restated only TO PARQUET, and SET STORAGE POLICY replaces the whole policy rather than merging into it.

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

Requirements​

How it works​

Partition lifecycle​

TTL evaluation​

Storage policy vs TTL​

Setting a storage policy​

At table creation​

On existing tables​

TTL duration format​

Ordering constraint​

Disabling and enabling​

Removing a storage policy​

Checking storage policies​

Replication​

Configuration​

Permissions​

End-to-end example​

Guidelines​