multi target DATA_SOURCE_NAME has issues on a port != 5432

I consistently have problems using DATA_SOURCE_NAME with more than one URI if the ports are not standard.

I understand from this sentences:

Also, you can set a list of sources to scrape different instances from the one exporter setup. Just define a comma separated string.

sudo -u postgres DATA_SOURCE_NAME="port=5432,port=6432" postgres_exporter

What I did is to set this variable:

DATA_SOURCE_NAME="postgresql://postgres:xxx@10.1.201.11:5434/postgres?sslmode=disable,postgresql://postgres:xxx@10.1.201.11:5432/postgres?sslmode=disable"

just for readability I'll write it this way:

DB1=10.1.201.11:5434
DB2=10.1.201.11:5432
OPTS=postgres?sslmode=disable
DATA_SOURCE_NAME="postgresql://postgres:xxx@$DB1$OPTS,postgresql://postgres:xxx@$DB1$OPTS"

What did you do?

I tested each database alone, and it worked.

As long as DB1 and DB2 use port 5432 the exporter works and I get rows for each target (clearly on different servers). If I use other ports (5434, 5435...) I get an error:

# wget -O - localhost:9187/metrics
--2022-01-26 23:47:17--  http://localhost:9187/metrics
Resolving localhost (localhost)... 127.0.0.1
Connecting to localhost (localhost)|127.0.0.1|:9187... connected.
HTTP request sent, awaiting response... 500 Internal Server Error
2022-01-26 23:47:17 ERROR 500: Internal Server Error.

What did you expect to see?
I expect it to work correctly on any port...

Environment

I did the tests with PostgreSQL 14 on Ubuntu 20.04 using binary 0.10.0

# uname -srm
Linux 5.4.0-80-generic x86_64

# postgres_exporter --version
postgres_exporter, version 0.10.0 (branch: HEAD, revision: 57719ba53cac428769aaf3c4c0bb742df3cfca98)
  build user:       root@4dcb2c7f1315
  build date:       20210709-11:49:20
  go version:       go1.16.5
  platform:         linux/amd64

• postgres_exporter flags:

not using any flags

I initially verified the same behaviour working in kubernetes.

Start by reproducing the issue in postgres_exporter with DATA_SOURCE_NAME containing multiple PostgreSQL URIs that use both standard and nonstandard ports, then request localhost:9187/metrics. Trace the multi-target parsing and connection path to identify why nonstandard ports produce HTTP 500; done means metrics work for every configured port.