# ssl_min_protocol_version

> ssl_min_protocol_version is the PostgreSQL setting that defines the minimum SSL/TLS protocol version to use.
---

> [!NOTE]
> **Fact — official short description:** “Sets the minimum SSL/TLS protocol version to use.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `enum` | Upstream pg_settings type |
| Context | `sighup` | Takes effect after configuration reload |
| Unit | — | Raw unit |
| Range | — | Raw limits in the last observed version |
| Enum values | `TLSv1`, `TLSv1.1`, `TLSv1.2`, `TLSv1.3` | — for non-enum types |
| Category | Connections and Authentication / SSL | Upstream classification |
| Latest boot value | `TLSv1.2` | TLSv1.2 |
{.fields meta="-"}

## Lifecycle {#lifecycle}

| Fact | Value |
| --- | --- |
| First observed | PG12 |
| Present in | PG12–19 Beta 3 |
| Removed in | No |
| Introduction commit | [`e73e67c71959`](https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=e73e67c719593c1c16139cc6c516d8379f22f182) — Add settings to control SSL/TLS protocol version |
| Commit date | 2018-11-20 |
| Discussion | [thread 1](https://www.postgresql.org/message-id/flat/1822da87-b862-041a-9fc2-d0310c3da173@2ndquadrant.com) |

## Default history {#default-history}

| Versions | Raw `boot_val` | Unit | Human value |
| --- | --- | --- | --- |
| PG12 | `TLSv1` | — | TLSv1 |
| PG13–19 Beta 3 | `TLSv1.2` | — | TLSv1.2 |
{.full-width caption="Measured PG9.0–19 Beta 3 boot defaults"}

## How it works {#mechanism}

ssl_min_protocol_version sets the minimum SSL/TLS protocol version to use. Connections negotiating below the floor are rejected; the upstream default moved from TLSv1 in PostgreSQL 12 to TLSv1.2 in PostgreSQL 13.

ssl_min_protocol_version is a SIGHUP-context setting: a configuration reload activates the new server value without a restart; subsequent operations that consult it use the refreshed value. Existing TLS sessions are not renegotiated.

It participates in the TLS context used for new handshakes. ssl enables transport, pg_hba.conf decides which connection classes require it, and the certificate, key, CA, revocation, protocol, and cipher settings must form one valid policy.

## Tuning advice {#tuning-advice}

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

| Workload | Guidance |
| --- | --- |
| OLTP | Treat ssl_min_protocol_version as transport-security policy rather than a performance knob. Follow the organization's TLS baseline and test certificate rotation, reload, and every client class. |
| OLAP | Use the same TLS floor for analytical traffic; benchmark only after correctness because bulk transfer may expose CPU cost but is not a reason to accept obsolete protocols. |
| Small nodes | Keep ssl_min_protocol_version simple and secure, using managed certificates and library defaults reviewed for the installed OpenSSL version. Rehearse renewal before expiry. |
{.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: PG12–19 Beta 3 unmodified; OLAP: PG12–19 Beta 3 unmodified; CRIT: PG12–19 Beta 3 unmodified; TINY: PG12–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

## Common pitfalls {#common-pitfalls}

- Editing ssl_min_protocol_version without reloading configuration and verifying the effective value and subsequent behavior.
- Updating only one TLS file or policy knob and leaving an invalid chain, unreadable key, or incompatible protocol set.
- Assuming a reload renegotiates existing sessions; TLS policy changes affect new handshakes.
- Changing ssl_min_protocol_version globally without a rollback plan and a client or operational compatibility test.

## Related parameters {#related-parameters}

[`ssl_ciphers`](/parameters/ssl-ciphers/) · [`ssl_tls13_ciphers`](/parameters/ssl-tls13-ciphers/) · [`ssl_max_protocol_version`](/parameters/ssl-max-protocol-version/) · [`ssl_prefer_server_ciphers`](/parameters/ssl-prefer-server-ciphers/) · [`ssl_groups`](/parameters/ssl-groups/)

## References {#references}

- [PostgreSQL 19 Beta 3 — ssl_min_protocol_version](https://www.postgresql.org/docs/19/runtime-config-connection.html#GUC-SSL-MIN-PROTOCOL-VERSION)
- [PostgreSQL 19 release notes](https://www.postgresql.org/docs/19/release-19.html)
- [Machine-readable GUC export](/data/guc.jsonl)