89 lines
2.3 KiB
C
89 lines
2.3 KiB
C
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/*
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* This program is based on
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* src/test/examples/testlibpq.c (example 33.1)
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* from section 33.21 of the PostgreSQL documentation
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* (https://www.postgresql.org/docs/13/libpq-example.html)
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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 <time.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(int argc, char **argv)
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{
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const char *conninfo;
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PGconn *conn;
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PGresult *res;
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int nFields;
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int i,
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j;
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struct timespec ts0, ts1, ts2, ts3, ts4;
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/*
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* If the user supplies a parameter on the command line, use it as the
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* conninfo string; otherwise default to setting dbname=postgres and using
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* environment variables or defaults for all other connection parameters.
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*/
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if (argc > 1)
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conninfo = argv[1];
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else
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conninfo = "";
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clock_gettime(CLOCK_MONOTONIC, &ts0);
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/* Make a connection to the database */
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conn = PQconnectdb(conninfo);
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/* Check to see that the backend connection was successfully made */
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if (PQstatus(conn) != CONNECTION_OK)
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{
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fprintf(stderr, "Connection to database failed: %s",
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PQerrorMessage(conn));
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exit_nicely(conn);
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}
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clock_gettime(CLOCK_MONOTONIC, &ts1);
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res = PQexec(conn, "select current_timestamp");
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if (PQresultStatus(res) != PGRES_TUPLES_OK)
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{
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fprintf(stderr, "Select command failed: %s", PQerrorMessage(conn));
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PQclear(res);
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exit_nicely(conn);
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}
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/* first, print out the attribute names */
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nFields = PQnfields(res);
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for (i = 0; i < nFields; i++)
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printf("%-15s", PQfname(res, i));
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printf("\n\n");
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/* next, print out the rows */
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for (i = 0; i < PQntuples(res); i++)
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{
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for (j = 0; j < nFields; j++)
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printf("%-15s", PQgetvalue(res, i, j));
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printf("\n");
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}
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PQclear(res);
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clock_gettime(CLOCK_MONOTONIC, &ts2);
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/* close the connection to the database and cleanup */
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PQfinish(conn);
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clock_gettime(CLOCK_MONOTONIC, &ts3);
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printf("%f connect\n", (ts1.tv_sec - ts0.tv_sec) + (ts1.tv_nsec - ts0.tv_nsec) * 1E-9);
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printf("%f session\n", (ts3.tv_sec - ts0.tv_sec) + (ts3.tv_nsec - ts0.tv_nsec) * 1E-9);
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return 0;
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}
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