C client library

• Non-blocking query execution
  • int PQsetnonblocking(PGconn *conn, int arg) - set a connection to be non-blocking
  • int PQsendQuery(PGconn *conn,const char *query) - send (buffer) a query
  • int PQflush(PGconn *conn) - attempt to flush buffer
  • PQconsumeInput(PGconn *conn) - read data from connection into underlying buffer
  • int PQisBusy(PGconn *conn) - is the query still being processed?
  • int PQrequestCancel(PGconn *conn) - cancel a running query
  • PGresult *PQgetResult(PGconn *conn)
    • Return usual result handle
    • Only call once !PQisBusy() to avoid blocking
    
    
  • Usage:
    • Call PQsetnonblocking();
    • Call PQsendQuery();
    • Do other stuff
    • PQconsumeInput() / PQisBusy() loop; select()
    • Process results, when ready
    
    
  • Useful applications: high-throughput applications, computationally intensive applicaitons

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