Commits on Aug 17, 2023

1. Fix FATAL in function client_proto(): bad client state: 6/7 …

   The cancel request protocol is very simple:
   1. Clients send a cancel key
   2. Server cancels the query running on the matching backend
   3. The server closes the socket to indicate the cancel request was
      handled
   
   At no point after sending the cancel key the client is required to send
   any data, and if it does it won't get a response anyway because the
   server would close the connection. So most clients don't, specifically
   all libpq based client don't.
   
   The Go client however, sends a Terminate ('X') packet before closing the
   cancel socket from its own side (usually due to a 10 second timeout).
   This would cause a crash in PgBouncer, because PgBouncer would still
   listen on the client socket, but on receiving any data we wouldreport a
   fatal error. This PR fixes that fatal error by stopping to listen on the
   client socket once we've received the cancel key (i.e. when we change
   the client state to CL_WAITING_CANCEL).
   
   I was able to reproduce both of the errors reported by @raymasson and
   confirmed that after this change the errors would not occur again.
   
   Reproducing this with libpq based clients is not possible, except when
   manually attaching to the client using `gdb` and manually running `send`
   on the cancel request its socket. So no test is added, since our test
   suite uses psycopg which uses libpq under the hood.
   
   Fixes pgbouncer#904
   
   Related to pgbouncer#717

   

   JelteF committed Aug 17, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for 4757046
   • Browse repository at this point

   Copy the full SHA

   4757046 View commit details

   Browse the repository at this point in the history