# dynamic_library_path

> dynamic_library_path is the PostgreSQL setting that defines the path for dynamically loadable modules.
---

> [!NOTE]
> **Fact — official short description:** “Sets the path for dynamically loadable modules.”

## Identity {#identity}

| Field | Value | Meaning |
| --- | --- | --- |
| Type | `string` | Upstream pg_settings type |
| Context | `superuser` | Settable at runtime by a superuser |
| Unit | — | Raw unit |
| Range | — | Raw limits in the last observed version |
| Enum values | — | — for non-enum types |
| Category | Client Connection Defaults / Other Defaults | Upstream classification |
| Latest boot value | `$libdir` | $libdir |
{.fields meta="-"}

## Lifecycle {#lifecycle}

| Fact | Value |
| --- | --- |
| First observed | PG9.0 (research boundary) |
| Present in | PG9.0–19 Beta 3 |
| Removed in | No |
| Introduction commit | Not asserted: predates the PG9.0 research boundary |
| Commit date | — |
| Discussion | — |

## Default history {#default-history}

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

## How it works {#mechanism}

dynamic_library_path sets the path for dynamically loadable modules. If a dynamically loadable module needs to be opened and the specified name does not have a directory component (i.e., the name does not contain a slash), the system will search this path for the specified file. The search is used only for module names without a directory component; $libdir points at PostgreSQL's version-specific library directory.

dynamic_library_path is a SUPERUSER-context setting. Superuser or a role granted the appropriate SET privilege can change it for a session, while ALTER ROLE or ALTER DATABASE can establish a default for future sessions.

Library discovery and preloading interact with installed binary versions, extension control files, server or backend startup, and the module's own GUCs.

## Tuning advice {#tuning-advice}

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

| Workload | Guidance |
| --- | --- |
| OLTP | Keep dynamic_library_path restricted to administrator-controlled, version-matched directories and retain $libdir. Use absolute module paths only when deployment and rollback manage them explicitly. |
| OLAP | Add a search directory only for a reviewed analytical extension package present identically on every failover target. |
| Small nodes | Keep $libdir. Expanding the native-code search path provides no capacity gain and increases packaging and trust risk. |
{.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: PG9.0–19 Beta 3 unmodified; OLAP: PG9.0–19 Beta 3 unmodified; CRIT: PG9.0–19 Beta 3 unmodified; TINY: PG9.0–19 Beta 3 unmodified. No Pigsty-specific rationale is inferred from an absent override.

## Common pitfalls {#common-pitfalls}

- Changing dynamic_library_path in one session and assuming role defaults, database defaults, or other pooled sessions changed with it.
- Naming a missing or ABI-incompatible module and causing connection failure or a server that cannot start.
- Treating a search or preload path as harmless even though it defines which native code the server trusts.
- Changing dynamic_library_path globally without a rollback plan and a client or operational compatibility test.

## Related parameters {#related-parameters}

[`shared_preload_libraries`](/parameters/shared-preload-libraries/) · [`session_preload_libraries`](/parameters/session-preload-libraries/) · [`local_preload_libraries`](/parameters/local-preload-libraries/) · [`jit_provider`](/parameters/jit-provider/) · [`extension_control_path`](/parameters/extension-control-path/)

## References {#references}

- [PostgreSQL 19 Beta 3 — dynamic_library_path](https://www.postgresql.org/docs/19/runtime-config-client.html#GUC-DYNAMIC-LIBRARY-PATH)
- [PostgreSQL 19 release notes](https://www.postgresql.org/docs/19/release-19.html)
- [Machine-readable GUC export](/data/guc.jsonl)