Thread

1. Size limit for NOTIFY payload

   sulfinu@gmail.com — 2024-12-16T08:01:14Z

   Hello,
   
   according to the documentation
   <https://www.postgresql.org/docs/current/sql-notify.html>, the payload
   given in a NOTIFY statement must not exceed a certain limit *in bytes*. But
   the payload is a character string, therefore the limit remains unclear.
   
   What's the character encoding of the NOTIFY payload, is it the default
   database encoding?
   
   Thanks.
   

2. Re: Size limit for NOTIFY payload

   Tom Lane <tgl@sss.pgh.pa.us> — 2024-12-18T16:29:20Z

   sulfinu@gmail.com writes:
   > What's the character encoding of the NOTIFY payload, is it the default
   > database encoding?
   
   It's whatever encoding your database uses; NOTIFY doesn't do any
   transcoding.
   
   (We'd have to think harder about that if NOTIFY messages could cross
   database boundaries ... but they don't today.)
   
   			regards, tom lane
   
   
   
   

3. Re: Size limit for NOTIFY payload

   sulfinu@gmail.com — 2024-12-19T09:00:18Z

   Well, as I said, that's a *text* value with a *byte* limit. The
   documentation should definitely mention something like *"with the default
   database encoding"*.
   
   În mie., 18 dec. 2024 la 18:29, Tom Lane <tgl@sss.pgh.pa.us> a scris:
   
   > sulfinu@gmail.com writes:
   > > What's the character encoding of the NOTIFY payload, is it the default
   > > database encoding?
   >
   > It's whatever encoding your database uses; NOTIFY doesn't do any
   > transcoding.
   >
   > (We'd have to think harder about that if NOTIFY messages could cross
   > database boundaries ... but they don't today.)
   >
   >                         regards, tom lane
   >
   

4. Re: Size limit for NOTIFY payload

   Greg Sabino Mullane <htamfids@gmail.com> — 2024-12-20T14:16:30Z

   On Fri, Dec 20, 2024 at 5:53 AM <sulfinu@gmail.com> wrote:
   
   > Well, as I said, that's a *text* value with a *byte* limit. The
   > documentation should definitely mention something like *"with the default
   > database encoding"*.
   >
   
   I'm not sure why you think adding such wordage is needed. Bytes is bytes.
   Your application should be checking the number of bytes in the string sent
   to NOTIFY.
   
   On a related note, if you find yourself approaching the payload limits, you
   might want to rethink the way you are using LISTEN/NOTIFY.
   
   Cheers,
   Greg