src/factories/createPool.ts

@@ -1,4 +1,5 @@
 import {
+  Client as PgClient,
   Pool as PgPool,
 } from 'pg';
 import {
@@ -57,18 +58,23 @@ export const createPool = async (
     throw new Error('Unexpected state.');
   }
 
-  // This pool is only used to initialize the client.
-  const setupPool: PgPool = new Pool({
-    ...poolConfiguration,
-    max: 1,
+  const setupClient = new PgClient({
+    database: poolConfiguration.database,
+    host: poolConfiguration.host,
+    password: poolConfiguration.password,
+    port: poolConfiguration.port,
+    ssl: poolConfiguration.ssl,
+    user: poolConfiguration.user,
   });
 
+  await setupClient.connect();
+
   const getTypeParser = await createTypeOverrides(
-    setupPool,
+    setupClient,
     clientConfiguration.typeParsers,
   );
 
-  await setupPool.end();
+  await setupClient.end();
 
   const pool: PgPool = new Pool({
     ...poolConfiguration,

src/routines/createTypeOverrides.ts

@@ -1,5 +1,5 @@
 import {
-  type Pool as PgPool,
+  type Client as PgClient,
 } from 'pg';
 import {
   getTypeParser,
@@ -18,23 +18,19 @@ type PostgresType = {
 };
 
 export const createTypeOverrides = async (
-  pool: PgPool,
+  pool: PgClient,
   typeParsers: readonly TypeParser[],
 ) => {
   const typeNames = typeParsers.map((typeParser) => {
     return typeParser.name;
   });
 
-  const connection = await pool.connect();
-
   const postgresTypes: PostgresType[] = (
-    await connection.query('SELECT oid, typarray, typname FROM pg_type WHERE typname = ANY($1::text[])', [
+    await pool.query('SELECT oid, typarray, typname FROM pg_type WHERE typname = ANY($1::text[])', [
       typeNames,
     ])
   ).rows;
 
-  connection.release(true);
-
   const parsers = {};
 
   for (const typeParser of typeParsers) {