Function PostgresMain

src/backend/tcop/postgres.c:4994–6200

---------------------------------------------------------------- * PostgresMain * postgres main loop -- all backends, interactive or otherwise start here * * argc/argv are the command line arguments to be used. (When being forked * by the postmaster, these are not the original argv array of the process.) * dbname is the name of the database to connect to, or NULL if the database * name

 * ----------------------------------------------------------------
 */
void
PostgresMain(int argc, char *argv[],
			 const char *dbname,
			 const char *username)
{
	int			firstchar;
	StringInfoData input_message;
	sigjmp_buf	local_sigjmp_buf;
	volatile bool send_ready_for_query = true;
	bool		idle_in_transaction_timeout_enabled = false;
	bool		idle_session_timeout_enabled = false;

	/*
	 * CDB: Catch program error signals.
	 *
	 * Save our main thread-id for comparison during signals.
	 */
	main_tid = pthread_self();

	/* Initialize startup process environment if necessary. */
	if (!IsUnderPostmaster)
		InitStandaloneProcess(argv[0]);

#ifndef WIN32
	PostmasterPriority = getpriority(PRIO_PROCESS, 0);
#endif

	set_ps_display("startup");

	SetProcessingMode(InitProcessing);

	/*
	 * Set default values for command-line options.
	 */
	EchoQuery = false;

	if (!IsUnderPostmaster)
		InitializeGUCOptions();

	/*
	 * Parse command-line options.
	 */
	process_postgres_switches(argc, argv, PGC_POSTMASTER, &dbname);

	/* Must have gotten a database name, or have a default (the username) */
	if (dbname == NULL)
	{
		dbname = username;
		if (dbname == NULL)
			ereport(FATAL,
					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
					 errmsg("%s: no database nor user name specified",
							progname)));
	}

	/* Acquire configuration parameters, unless inherited from postmaster */
	if (!IsUnderPostmaster)
	{