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postgres.ts
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postgres.ts
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import pg, { PoolConfig, Pool } from "pg";
import {
ListKeyOptions,
RecordManagerInterface,
UpdateOptions,
} from "./base.js";
export type PostgresRecordManagerOptions = {
postgresConnectionOptions: PoolConfig;
tableName?: string;
};
export class PostgresRecordManager implements RecordManagerInterface {
lc_namespace = ["langchain", "recordmanagers", "postgres"];
pool: Pool;
tableName: string;
namespace: string;
constructor(namespace: string, config: PostgresRecordManagerOptions) {
const { postgresConnectionOptions, tableName } = config;
this.namespace = namespace;
this.pool = new pg.Pool(postgresConnectionOptions);
this.tableName = tableName || "upsertion_records";
}
async createSchema(): Promise<void> {
try {
await this.pool.query(`
CREATE TABLE IF NOT EXISTS "${this.tableName}" (
uuid UUID PRIMARY KEY DEFAULT gen_random_uuid(),
key TEXT NOT NULL,
namespace TEXT NOT NULL,
updated_at Double PRECISION NOT NULL,
group_id TEXT,
UNIQUE (key, namespace)
);
CREATE INDEX IF NOT EXISTS updated_at_index ON "${this.tableName}" (updated_at);
CREATE INDEX IF NOT EXISTS key_index ON "${this.tableName}" (key);
CREATE INDEX IF NOT EXISTS namespace_index ON "${this.tableName}" (namespace);
CREATE INDEX IF NOT EXISTS group_id_index ON "${this.tableName}" (group_id);`);
// eslint-disable-next-line @typescript-eslint/no-explicit-any
} catch (e: any) {
// This error indicates that the table already exists
// Due to asynchronous nature of the code, it is possible that
// the table is created between the time we check if it exists
// and the time we try to create it. It can be safely ignored.
if ("code" in e && e.code === "23505") {
return;
}
throw e;
}
}
async getTime(): Promise<number> {
const res = await this.pool.query(
"SELECT EXTRACT(EPOCH FROM CURRENT_TIMESTAMP)"
);
return Number.parseFloat(res.rows[0].extract);
}
/**
* Generates the SQL placeholders for a specific row at the provided index.
*
* @param index - The index of the row for which placeholders need to be generated.
* @param numOfColumns - The number of columns we are inserting data into.
* @returns The SQL placeholders for the row values.
*/
private generatePlaceholderForRowAt(
index: number,
numOfColumns: number
): string {
const placeholders = [];
for (let i = 0; i < numOfColumns; i += 1) {
placeholders.push(`$${index * numOfColumns + i + 1}`);
}
return `(${placeholders.join(", ")})`;
}
async update(keys: string[], updateOptions?: UpdateOptions): Promise<void> {
if (keys.length === 0) {
return;
}
const updatedAt = await this.getTime();
const { timeAtLeast, groupIds: _groupIds } = updateOptions ?? {};
if (timeAtLeast && updatedAt < timeAtLeast) {
throw new Error(
`Time sync issue with database ${updatedAt} < ${timeAtLeast}`
);
}
const groupIds = _groupIds ?? keys.map(() => null);
if (groupIds.length !== keys.length) {
throw new Error(
`Number of keys (${keys.length}) does not match number of group_ids ${groupIds.length})`
);
}
const recordsToUpsert = keys.map((key, i) => [
key,
this.namespace,
updatedAt,
groupIds[i],
]);
const valuesPlaceholders = recordsToUpsert
.map((_, j) =>
this.generatePlaceholderForRowAt(j, recordsToUpsert[0].length)
)
.join(", ");
const query = `INSERT INTO "${this.tableName}" (key, namespace, updated_at, group_id) VALUES ${valuesPlaceholders} ON CONFLICT (key, namespace) DO UPDATE SET updated_at = EXCLUDED.updated_at;`;
await this.pool.query(query, recordsToUpsert.flat());
}
async exists(keys: string[]): Promise<boolean[]> {
if (keys.length === 0) {
return [];
}
const startIndex = 2;
const arrayPlaceholders = keys
.map((_, i) => `$${i + startIndex}`)
.join(", ");
const query = `
SELECT k, (key is not null) ex from unnest(ARRAY[${arrayPlaceholders}]) k left join "${this.tableName}" on k=key and namespace = $1;
`;
const res = await this.pool.query(query, [this.namespace, ...keys.flat()]);
return res.rows.map((row: { ex: boolean }) => row.ex);
}
async listKeys(options?: ListKeyOptions): Promise<string[]> {
const { before, after, limit, groupIds } = options ?? {};
let query = `SELECT key FROM "${this.tableName}" WHERE namespace = $1`;
const values: (string | number | (string | null)[])[] = [this.namespace];
let index = 2;
if (before) {
values.push(before);
query += ` AND updated_at < $${index}`;
index += 1;
}
if (after) {
values.push(after);
query += ` AND updated_at > $${index}`;
index += 1;
}
if (limit) {
values.push(limit);
query += ` LIMIT $${index}`;
index += 1;
}
if (groupIds) {
values.push(groupIds);
query += ` AND group_id = ANY($${index})`;
index += 1;
}
query += ";";
const res = await this.pool.query(query, values);
return res.rows.map((row: { key: string }) => row.key);
}
async deleteKeys(keys: string[]): Promise<void> {
if (keys.length === 0) {
return;
}
const query = `DELETE FROM "${this.tableName}" WHERE namespace = $1 AND key = ANY($2);`;
await this.pool.query(query, [this.namespace, keys]);
}
/**
* Terminates the connection pool.
* @returns {Promise<void>}
*/
async end(): Promise<void> {
await this.pool.end();
}
}