Function write_syslogger_file_binary

src/backend/postmaster/syslogger.c:1738–1766

* Write binary data to the currently open logfile * * On Windows the data arriving in the pipe already has CR/LF newlines, * so we must send it to the file without further translation. * * This is exported so that elog.c can call it when MyBackendType is B_LOGGER. * This allows the syslogger process to record elog messages of its own, * even though its stderr does not point at the syslog pi

 * even though its stderr does not point at the syslog pipe.
 */
void write_syslogger_file_binary(const char *buffer, int count, int destination)
{
	FILE	   *logfile;

	/*
	 * If we're told to write to csvlogFile, but it's not open, dump the data
	 * to syslogFile (which is always open) instead.  This can happen if CSV
	 * output is enabled after postmaster start and we've been unable to open
	 * csvlogFile.  There are also race conditions during a parameter change
	 * whereby backends might send us CSV output before we open csvlogFile or
	 * after we close it.  Writing CSV-formatted output to the regular log
	 * file isn't great, but it beats dropping log output on the floor.
	 *
	 * Think not to improve this by trying to open csvlogFile on-the-fly.  Any
	 * failure in that would lead to recursion.
	 *
	 * The following logic is a little different from GP7.
	 * We follow the upstream pattern. Use ternary operator to set the `logfile`
	 * variable to csvlogFile or syslogFile in different situations.
	 * Thus we can write to it directly without if-else sentences.
	 * We need to ensure that everytime we call write_syslogger_file_binary, the
	 * destination should always be LOG_DESTINATION_CSVLOG
	 * or LOG_DESTINATION_STDERR.
	 */
	logfile = (destination == LOG_DESTINATION_CSVLOG &&
			   csvlogFile != NULL) ? csvlogFile : syslogFile;

	write_binary_to_file(buffer, count, logfile);
}
/*
 * Write text to the currently open logfile
 *