Unable to set Codec to Custom Type (pguint)

• asyncpg version: 0.20.0
• PostgreSQL version: 12.2
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: No, N/A, N/A
• Python version: 3.8.0
• Platform: Linux 64bit (Ubuntu 18.04)
• Do you use pgbouncer?: No
• Did you install asyncpg with pip?: Yes
• If you built asyncpg locally, which version of Cython did you use?: N/A
• Can the issue be reproduced under both asyncio and
  uvloop?: That's actually what I'm using.

I am using the user extension pguint (there's a pg11&12 branch) and it's installed fine. I'm trying to load ~100GB of article data onto my database, so I'm using the binary copy functions.

I created a binary encoder and decoder:

await con.set_type_codec( 'uint1', encoder=lambda x: struct.pack('!B',x), decoder=lambda x: struct.unpack('!B',x), format='binary')

But when I try to use it, I get:

Caught Insert Error.  UID:2419 EX: no binary input function available for type uint1

as my error. I tried delving into the source of this project but wasn't able to glean much. Does this error mean that the postgres extension itself is missing the required function on its end?

As a side note: I wrote a correct encoder/decoder (both text and binary) for the tsvector type, I want to submit a pull request but have no idea where I should put the new code, want to point me in the right direction?

also, should I be including the postgres varlena header in my binary encoding function outputs? or does your code do that?

从 set_type_codec 和报告中描述的二进制 COPY 函数开始，在 PostgreSQL 12.2、asyncpg 0.20.0、Python 3.8 和 uvloop 环境下复现 uint1 失败。检查 pguint 的二进制输入行为以及关于 varlena 标头的问题。确定原因和受支持的指导，并明确 tsvector codec 贡献应放在哪里，即表示完成。