How to support extended query protocol (Parse, Describe, Bind, Execute)?

[Ace002]

Hi! 👋

I’m building a custom PostgreSQL wire-compatible proxy using psql-wire, and it works perfectly with psql or other simple clients.

However, I’m running into trouble when trying to support Prisma (prisma reference), which relies on the extended query protocol. When Prisma connects, the connection dies silently — no error, no panic, and nothing gets logged. After some digging, I noticed Prisma sends:

• Parse
• Describe
• Bind
• Execute

I can't find documentation or hooks in psql-wire to handle these message types. I saw there’s no WithDescribe or similar extension points — only NewStatement for simple Query.

Questions:

• Does psql-wire support the extended query protocol (Parse, Describe, Bind, Execute)?
• If not yet supported, is there a clean way to hook into or override the message dispatch behavior?
• Is there an upstream plan to support it?

Thanks in advance! 🙏

Loving how simple psql-wire is to work with — hoping to extend it just enough to make it work with Prisma as well.

[jeroenrinzema]

Hi @Ace002, we do support the extended protocol there might be a bug in the protocol causing Prisma to receive a unexpected message from the PSQL wire protocol. Would you be able to share a small sample project with me allowing us to replicate the issue?

[jeroenrinzema]

Hi @Ace002, I think I have found the bug(s). I noticed that in the mock response, you’re trying to return a string within the int column. To fix this, you could simply return an int.
https://github.com/Ace002/poc-prisma-psql-wire/blob/e39ccd9179c0ab44f04b1314a917fd856e389729/psql_wire_app/handlers/handler.go#L53

The second issue is related to the OID types. You’ve assigned the OID type _text to both columns, which represents an array of text within PostgreSQL. To fix this, simply use the oid.T_text type instead.
https://github.com/Ace002/poc-prisma-psql-wire/blob/e39ccd9179c0ab44f04b1314a917fd856e389729/psql_wire_app/handlers/handler.go#L28

I managed to run your PoC locally after making these changes. Thanks for providing a detailed PoC and instructions on how to run it!

[Ace002]

Hi @jeroenrinzema , thanks for your time on trying my PoC. Is Ace002/poc-prisma-psql-wire#1 the same as what you mean? since when I tried to run the docker compose in psql_wire_app, it returns error like the following

psql_client_test-1    | ERROR:  write row failed: unable to encode 123 into text format for _numeric (OID 1231): cannot find encode plan
psql_wire_server-1  | 2025/08/28 05:19:00 ERROR an unexpected error got returned while serving a client connection err="read tcp 172.26.0.2:5432->[192.168.65.1:55552](http://192.168.65.1:55552/): use of closed network connection"

Am I doing something wrong?

Thanks!

[jeroenrinzema]

@Ace002 did you update the values your writing back to the client as well? I think the value 123 is still a string please try changing it to a int.

[Ace002]

@jeroenrinzema isn't the one that you mean reflect in this diff?
https://github.com/Ace002/poc-prisma-psql-wire/pull/1/files#diff-3b93e254b99101609702c5134be050f94db7493777de09b1ef4da01f10e2cf2eR53

[Ace002]

Hello @jeroenrinzema , sorry for tagging you back, do you have any updates regarding to this? Thanks!