# data_sync_retry

> data_sync_retry — Whether to continue running after a failure to sync data files. Observed in PG9.4–19 Beta 3; its last measured boot default is off in PG19 Beta 3, with postmaster context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA.
---

> [!NOTE]
> **Fact — official short description:** “Whether to continue running after a failure to sync data files.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `bool` | Upstream pg_settings type |
| Context | `postmaster` | Requires a server restart |
| Unit | — | Raw unit |
| Range | — | Raw limits in the last observed version |
| Enum values | — | — for non-enum types |
| Category | Error Handling | Upstream classification |
| Latest boot value | `off` | off |
{.fields meta="-"}

## Lifecycle {#lifecycle}

| Fact | Value |
| --- | --- |
| First observed | PG9.4 |
| Present in | PG9.4–19 Beta 3 |
| Removed in | No |
| Introduction commit | [`f1ff5f51d249`](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=f1ff5f51d2490817c2b3bba202f4e2c73a846389) — PANIC on fsync() failure. |
| Commit date | 2018-11-19 |
| Discussion | [thread 1](https://postgr.es/m/20180427222842.in2e4mibx45zdth5%40alap3.anarazel.de) |

## Default history {#default-history}

| Versions | Raw `boot_val` | Unit | Human value |
| --- | --- | --- | --- |
| PG9.4–19 Beta 3 | `off` | — | off |
{.full-width caption="Measured PG9.0–19 Beta 3 boot defaults"}

## How it works {#mechanism}

Whether to continue running after a failure to sync data files. The value is fixed when the server starts, so changing it requires a restart.

After a data-file fsync failure, the default behavior treats shared buffers as potentially inconsistent and raises PANIC so crash recovery re-establishes state. Continuing can lose knowledge of dirty pages and is intended only for platforms whose kernel semantics make retry safe.

Monitor and change data_sync_retry together with restart_after_crash, recovery_init_sync_method, fsync. Validate on the relevant server role and real workload, then use its postmaster context to choose session change, reload, or restart; a historical boot default is not the current effective value.

## Tuning advice {#tuning-advice}

> [!TIP]
> **Advice.** These are workload-specific starting points and must be validated with measurements.

| Workload | Guidance |
| --- | --- |
| OLTP | Change data_sync_retry only from an explicit failure model and measured evidence. Validate in a session/test environment, deploy according to its context, and retain a rollback value. |
| OLAP | Test separately under long queries, batch jobs, and peak concurrency rather than copying OLTP assumptions to analytical nodes. |
| Small nodes | Keep the default without a concrete problem; small systems should not trade global compatibility or failure semantics for a marginal gain. |
{.full-width}

## Pigsty {#pigsty}

Values use the fixed 8-vCPU, 32-GiB, 100-GiB SSD fixture and render the current Pigsty templates for PG19 Beta 3; this does not assert current Pigsty support for that historical or beta release.

| Template | Effective value | Versus upstream boot | Source expression |
| --- | --- | --- | --- |
| OLTP | Unmodified | — | — |
| OLAP | Unmodified | — | — |
| CRIT | Unmodified | — | — |
| TINY | Unmodified | — | — |
{.full-width}

> [!CAUTION]
> **Advice — pending human review.** Fact from the current Pigsty template projection: OLTP: PG9.4–19 Beta 3 unmodified; OLAP: PG9.4–19 Beta 3 unmodified; CRIT: PG9.4–19 Beta 3 unmodified; TINY: PG9.4–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

## Common pitfalls {#common-pitfalls}

- Enabling it on a platform where fsync failure loses dirty-page knowledge.
- Treating an I/O error as transient without replacing or fencing bad storage.
- Optimizing availability at the expense of silent corruption.
- Confusing the boot default of data_sync_retry with its current effective value.
- Ignoring its postmaster context when deciding when it takes effect.

## Related parameters {#related-parameters}

[`restart_after_crash`](/parameters/restart-after-crash/) · [`recovery_init_sync_method`](/parameters/recovery-init-sync-method/) · [`fsync`](/parameters/fsync/) · [`full_page_writes`](/parameters/full-page-writes/) · [`exit_on_error`](/parameters/exit-on-error/)

## References {#references}

- [PostgreSQL 19 Beta 3 — data_sync_retry](https://www.postgresql.org/docs/19/runtime-config-error-handling.html#GUC-DATA-SYNC-RETRY)
- [PostgreSQL 19 release notes](https://www.postgresql.org/docs/19/release-19.html)
- [Machine-readable GUC export](/data/guc.jsonl)