Getting started with the PostgreSQL sink

The PostgreSQL integration is used to mirror onchain data to a PostgreSQL database. Data is automatically inserted as it's produced by the chain, and it's invalidated in case of chain reorganizations.

• This integration can be used to populate SQL tables with data from one or more networks and smart contracts.
• Easily integrate with AI libraries such as Langchain.
• Change how tables are joined or queried without re-indexing.

apibara plugins install sink-postgres

This integration provides two modes:

• default mode: insert immutable data into the table. For example, a list of Transfer events.
• entity mode: insert mutable data into the table. Rows represent the state of entities at a specific block. For example, account balances.

Refer to each mode documentation to learn more about the required table schema and options.

Table schema

Apibara doesn't manage the target table schema for you, you need to create it using your favorite tool. The two modes require different table schemas, so refer to their documentation to learn more.

Two (or more) indexers, one table

You can have two or more indexers write data to the same table by leveraging the invalidate option. This option adds additional conditions to the invalidation query so that each indexer handles its rows only.

The following example shows an indexer that manages Transfer events, but only for the "ETH" token. Notice how data returned by the transform function has an additional "token_symbol" column. Without this column, the indexer would "forget" about data it wrote.

export const config = {
  // ...your config
  sinkType: "postgres",
  sinkOptions: {
    tableName: "transfers",
    invalidate: [{ column: "token_symbol", value: "ETH" }],
  },
};

export default function transform(block) {
  return [
    {
      ...myData,
      token_symbol: "ETH",
    },
  ];
}

TLS

Apibara supports different TLS modes to connect to your database. Refer to the options page to learn more.