/* CheckConnection
*
* Verify that we still have a good connection to the backend, and if not,
* see if it can be restored.
*
* Returns true if either the connection was still there, or it could be
* restored successfully; false otherwise. If, however, there was no
* connection and the session is non-interactive, this will exit the program
* with a code of EXIT_BADCONN.
*/
static bool
CheckConnection(void)
{
bool OK;
OK = ConnectionUp();
if (!OK)
{
if (!pset.cur_cmd_interactive)
{
psql_error("connection to server was lost\n");
exit(EXIT_BADCONN);
}
fputs(_("The connection to the server was lost. Attempting reset: "), stderr);
PQreset(pset.db);
OK = ConnectionUp();
if (!OK)
{
fputs(_("Failed.\n"), stderr);
PQfinish(pset.db);
pset.db = NULL;
ResetCancelConn();
UnsyncVariables();
}
else
fputs(_("Succeeded.\n"), stderr);
}
return OK;
}
/*
* SendQuery: send the query string to the backend
* (and print out results)
*
* Note: This is the "front door" way to send a query. That is, use it to
* send queries actually entered by the user. These queries will be subject to
* single step mode.
* To send "back door" queries (generated by slash commands, etc.) in a
* controlled way, use PSQLexec().
*
* Returns true if the query executed successfully, false otherwise.
*/
bool
SendQuery(const char *query)
{
PGresult *results;
PGTransactionStatusType transaction_status;
double elapsed_msec = 0;
bool OK = false;
bool on_error_rollback_savepoint = false;
static bool on_error_rollback_warning = false;
if (!pset.db)
{
psql_error("You are currently not connected to a database.\n");
goto sendquery_cleanup;
}
if (pset.singlestep)
{
char buf[3];
printf(_("***(Single step mode: verify command)*******************************************\n"
"%s\n"
"***(press return to proceed or enter x and return to cancel)********************\n"),
query);
fflush(stdout);
if (fgets(buf, sizeof(buf), stdin) != NULL)
if (buf[0] == 'x')
goto sendquery_cleanup;
}
else if (pset.echo == PSQL_ECHO_QUERIES)
{
puts(query);
fflush(stdout);
}
if (pset.logfile)
{
fprintf(pset.logfile,
_("********* QUERY **********\n"
"%s\n"
"**************************\n\n"), query);
fflush(pset.logfile);
}
SetCancelConn();
transaction_status = PQtransactionStatus(pset.db);
if (transaction_status == PQTRANS_IDLE &&
!pset.autocommit &&
!command_no_begin(query))
{
results = PQexec(pset.db, "BEGIN");
if (PQresultStatus(results) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
PQclear(results);
ResetCancelConn();
goto sendquery_cleanup;
}
PQclear(results);
transaction_status = PQtransactionStatus(pset.db);
}
if (transaction_status == PQTRANS_INTRANS &&
pset.on_error_rollback != PSQL_ERROR_ROLLBACK_OFF &&
(pset.cur_cmd_interactive ||
pset.on_error_rollback == PSQL_ERROR_ROLLBACK_ON))
{
if (on_error_rollback_warning == false && pset.sversion < 80000)
{
psql_error("The server (version %d.%d) does not support savepoints for ON_ERROR_ROLLBACK.\n",
pset.sversion / 10000, (pset.sversion / 100) % 100);
on_error_rollback_warning = true;
}
else
{
results = PQexec(pset.db, "SAVEPOINT pg_psql_temporary_savepoint");
if (PQresultStatus(results) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
PQclear(results);
ResetCancelConn();
goto sendquery_cleanup;
}
PQclear(results);
on_error_rollback_savepoint = true;
}
}
if (pset.fetch_count <= 0 || !is_select_command(query))
{
/* Default fetch-it-all-and-print mode */
instr_time before,
after;
if (pset.timing)
INSTR_TIME_SET_CURRENT(before);
results = PQexec(pset.db, query);
/* these operations are included in the timing result: */
ResetCancelConn();
OK = ProcessResult(&results);
if (pset.timing)
{
INSTR_TIME_SET_CURRENT(after);
INSTR_TIME_SUBTRACT(after, before);
elapsed_msec = INSTR_TIME_GET_MILLISEC(after);
}
/* but printing results isn't: */
if (OK && results)
OK = PrintQueryResults(results);
}
else
{
/* Fetch-in-segments mode */
OK = ExecQueryUsingCursor(query, &elapsed_msec);
ResetCancelConn();
results = NULL; /* PQclear(NULL) does nothing */
}
if (!OK && pset.echo == PSQL_ECHO_ERRORS)
psql_error("STATEMENT: %s\n", query);
/* If we made a temporary savepoint, possibly release/rollback */
if (on_error_rollback_savepoint)
{
const char *svptcmd = NULL;
transaction_status = PQtransactionStatus(pset.db);
switch (transaction_status)
{
case PQTRANS_INERROR:
/* We always rollback on an error */
svptcmd = "ROLLBACK TO pg_psql_temporary_savepoint";
break;
case PQTRANS_IDLE:
/* If they are no longer in a transaction, then do nothing */
break;
case PQTRANS_INTRANS:
/*
* Do nothing if they are messing with savepoints themselves:
* If the user did RELEASE or ROLLBACK, our savepoint is gone.
* If they issued a SAVEPOINT, releasing ours would remove
* theirs.
*/
if (results &&
(strcmp(PQcmdStatus(results), "SAVEPOINT") == 0 ||
strcmp(PQcmdStatus(results), "RELEASE") == 0 ||
strcmp(PQcmdStatus(results), "ROLLBACK") == 0))
svptcmd = NULL;
else
svptcmd = "RELEASE pg_psql_temporary_savepoint";
break;
case PQTRANS_ACTIVE:
case PQTRANS_UNKNOWN:
default:
OK = false;
/* PQTRANS_UNKNOWN is expected given a broken connection. */
if (transaction_status != PQTRANS_UNKNOWN || ConnectionUp())
psql_error("unexpected transaction status (%d)\n",
transaction_status);
break;
}
if (svptcmd)
{
PGresult *svptres;
svptres = PQexec(pset.db, svptcmd);
if (PQresultStatus(svptres) != PGRES_COMMAND_OK)
{
psql_error("%s", PQerrorMessage(pset.db));
PQclear(svptres);
OK = false;
PQclear(results);
ResetCancelConn();
goto sendquery_cleanup;
}
PQclear(svptres);
}
}
PQclear(results);
/* Possible microtiming output */
if (pset.timing)
printf(_("Time: %.3f ms\n"), elapsed_msec);
/* check for events that may occur during query execution */
if (pset.encoding != PQclientEncoding(pset.db) &&
PQclientEncoding(pset.db) >= 0)
{
/* track effects of SET CLIENT_ENCODING */
pset.encoding = PQclientEncoding(pset.db);
pset.popt.topt.encoding = pset.encoding;
SetVariable(pset.vars, "ENCODING",
pg_encoding_to_char(pset.encoding));
}
PrintNotifications();
/* perform cleanup that should occur after any attempted query */
sendquery_cleanup:
/* reset \g's output-to-filename trigger */
if (pset.gfname)
{
free(pset.gfname);
pset.gfname = NULL;
}
/* reset \gset trigger */
if (pset.gset_prefix)
{
free(pset.gset_prefix);
pset.gset_prefix = NULL;
}
return OK;
}
