# IvorySQL

> PostgreSQL fork with oracle (grammar) compatibility
---

[IvorySQL](https://www.ivorysql.org/) is an open-source “Oracle-compatible” PostgreSQL kernel, developed by [**HighGo**](https://www.highgo.com/), licensed under Apache 2.0.

The Oracle compatibility here refers to compatibility at the PL/SQL, syntax, built-in functions, data types, system views, MERGE, and GUC parameter levels.
It’s not a wire protocol compatibility like [**Babelfish**](/docs/pgsql/kernel/babelfish), [**openHalo**](/docs/pgsql/kernel/openhalo/), or [**FerretDB**](/docs/ferret/) that allows using the original client drivers.
Users still need to use PostgreSQL client tools to access IvorySQL, but can use Oracle-compatible syntax.

Currently, IvorySQL’s latest version **5.0** maintains compatibility with PostgreSQL's latest minor version 18.0,
and provides binary RPM/DEB packages for mainstream Linux distributions. Pigsty offers the option to replace the native PostgreSQL with the IvorySQL kernel in PG RDS.

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## Quick Start

Use the standard procedure to [**install**](/docs/install/start) Pigsty with the [`ivory`](https://github.com/pgsty/pigsty/blob/v3.7.0/conf/ivory.yml) configuration template:

```bash
curl -fsSL https://repo.pigsty.io/get | bash -s v3.7.0; cd ~/pigsty;
./configure -c ivory     # Use IvorySQL configuration template
./install.yml            # Run installation playbook
```

For production deployments, you should edit the auto-generated `pigsty.yml` configuration file to modify parameters like passwords before executing `./install.yml` for deployment.

The latest IvorySQL 5.0 is equivalent to PostgreSQL 18.0 Any client tool compatible with PostgreSQL’s wire protocol can access IvorySQL clusters.

By default, you can use a PostgreSQL client to access through the alternative `1521` port, which enables Oracle compatibility mode by default.


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## Configuration Instructions

To use the IvorySQL kernel in Pigsty, modify the following four configuration parameters:

- [`pg_mode`](/docs/pgsql/param/#pg_mode): Use `ivory` compatibility mode
- [`repo_extra_packages`](/docs/pgsql/param/#pg_mode): Download `ivorysql` packages
- [`pg_packages`](/docs/pgsql/param/#pg_mode): Install `ivorysql` packages
- [`pg_libs`](/docs/pgsql/param/#pg_mode): Load Oracle syntax compatibility extensions

It's that simple — just add these four lines to the global variables in the configuration file, and Pigsty will replace the native PostgreSQL kernel with IvorySQL:

```yaml
pg_mode: ivory                           # IvorySQL compatibility mode, uses IvorySQL binaries
pg_packages: [ ivorysql, pgsql-common ]  # Install ivorysql, replacing pgsql-main kernel
pg_libs: 'liboracle_parser, pg_stat_statements, auto_explain'  # Load Oracle compatibility extensions
repo_extra_packages: [ ivorysql ]        # Download ivorysql packages
```

IvorySQL also provides a series of [new GUC parameters](https://docs.ivorysql.org/en/ivorysql-doc/v5.0) that can be specified in [`pg_parameters`](/docs/pgsql/param/#pg_parameters).

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## Extensions

Most of the **PGSQL** modules’ [**extension**](/docs/pgsql/extension/) (non-SQL classes) cannot be used directly on the IvorySQL kernel.
If you need to use them, you need to recompile and install from source code for the new kernel.

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## Caveats

- The IvorySQL software package is located in the `pigsty-infra` repository, not in `pigsty-pgsql` or `pigsty-ivory` repositories.
- Pigsty does not assume any warranty for using the IvorySQL kernel, and any issues or requests should be addressed to the manufacturer.