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112 lines
2.5 KiB
C
112 lines
2.5 KiB
C
/*
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* testlibpq2.c
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* Test of the asynchronous notification interface
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*
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populate a database with the following:
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CREATE TABLE TBL1 (i int4);
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CREATE TABLE TBL2 (i int4);
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CREATE RULE r1 AS ON INSERT TO TBL1 DO [INSERT INTO TBL2 values (new.i); NOTIFY TBL2];
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* Then start up this program
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* After the program has begun, do
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INSERT INTO TBL1 values (10);
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*
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "libpq-fe.h"
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static void
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exit_nicely(PGconn *conn)
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{
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PQfinish(conn);
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exit(1);
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}
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int
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main()
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{
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char *pghost,
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*pgport,
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*pgoptions,
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*pgtty;
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char *dbName;
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/*
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* int nFields; int i, j;
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*/
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PGconn *conn;
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PGresult *res;
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PGnotify *notify;
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/*
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* begin, by setting the parameters for a backend connection if the
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* parameters are null, then the system will try to use reasonable
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* defaults by looking up environment variables or, failing that,
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* using hardwired constants
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*/
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pghost = NULL; /* host name of the backend server */
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pgport = NULL; /* port of the backend server */
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pgoptions = NULL; /* special options to start up the backend
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* server */
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pgtty = NULL; /* debugging tty for the backend server */
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dbName = getenv("USER"); /* change this to the name of your test
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* database */
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/* make a connection to the database */
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conn = PQsetdb(pghost, pgport, pgoptions, pgtty, dbName);
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/* check to see that the backend connection was successfully made */
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if (PQstatus(conn) == CONNECTION_BAD)
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{
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fprintf(stderr, "Connection to database '%s' failed.\n", dbName);
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fprintf(stderr, "%s", PQerrorMessage(conn));
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exit_nicely(conn);
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}
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res = PQexec(conn, "LISTEN TBL2");
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if (PQresultStatus(res) != PGRES_COMMAND_OK)
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{
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fprintf(stderr, "LISTEN command failed\n");
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PQclear(res);
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exit_nicely(conn);
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}
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/*
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* should PQclear PGresult whenever it is no longer needed to avoid
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* memory leaks
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*/
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PQclear(res);
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while (1)
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{
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/* async notification only come back as a result of a query */
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/* we can send empty queries */
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res = PQexec(conn, " ");
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/* printf("res->status = %s\n", PQresStatus(PQresultStatus(res))); */
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/* check for asynchronous returns */
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notify = PQnotifies(conn);
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if (notify)
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{
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fprintf(stderr,
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"ASYNC NOTIFY of '%s' from backend pid '%d' received\n",
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notify->relname, notify->be_pid);
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free(notify);
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break;
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}
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PQclear(res);
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}
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/* close the connection to the database and cleanup */
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PQfinish(conn);
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return 0; /* Though PQfinish(conn1) has called
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* exit(1) */
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}
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