Function GenerateRecoveryConfig

src/fe_utils/recovery_gen.c:24–110

* Write recovery configuration contents into a fresh PQExpBuffer, and * return it. */

 * return it.
 */
PQExpBuffer
GenerateRecoveryConfig(PGconn *pgconn, char *replication_slot)
{
	PQconninfoOption *connOptions;
	PQExpBufferData conninfo_buf;
	char	   *escaped;
	PQExpBuffer contents;

	Assert(pgconn != NULL);

	contents = createPQExpBuffer();
	if (!contents)
	{
		pg_log_error("out of memory");
		exit(1);
	}

	/*
	 * In PostgreSQL 12 and newer versions, standby_mode is gone, replaced by
	 * standby.signal to trigger a standby state at recovery.
	 */
	if (PQserverVersion(pgconn) < MINIMUM_VERSION_FOR_RECOVERY_GUC)
		appendPQExpBufferStr(contents, "standby_mode = 'on'\n");

	connOptions = PQconninfo(pgconn);
	if (connOptions == NULL)
	{
		pg_log_error("out of memory");
		exit(1);
	}

	initPQExpBuffer(&conninfo_buf);
	for (PQconninfoOption *opt = connOptions; opt && opt->keyword; opt++)
	{
		/* Omit empty settings and those libpqwalreceiver overrides. */
		if (strcmp(opt->keyword, "replication") == 0 ||
			strcmp(opt->keyword, "dbname") == 0 ||
			strcmp(opt->keyword, "fallback_application_name") == 0 ||
			(opt->val == NULL) ||
			(opt->val != NULL && opt->val[0] == '\0'))
			continue;

		/* Separate key-value pairs with spaces */
		if (conninfo_buf.len != 0)
			appendPQExpBufferChar(&conninfo_buf, ' ');

		/*
		 * Write "keyword=value" pieces, the value string is escaped and/or
		 * quoted if necessary.
		 */
		appendPQExpBuffer(&conninfo_buf, "%s=", opt->keyword);
		appendConnStrVal(&conninfo_buf, opt->val);
	}
	if (PQExpBufferDataBroken(conninfo_buf))
	{
		pg_log_error("out of memory");
		exit(1);
	}