diff options
Diffstat (limited to 'src/backend/utils/error/elog.c')
| -rw-r--r-- | src/backend/utils/error/elog.c | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c index f0b3b1feb06..7122b59b96a 100644 --- a/src/backend/utils/error/elog.c +++ b/src/backend/utils/error/elog.c @@ -1747,10 +1747,12 @@ write_eventlog(int level, const char *line, int len) static void write_console(const char *line, int len) { + int rc; + #ifdef WIN32 /* - * WriteConsoleW() will fail of stdout is redirected, so just fall through + * WriteConsoleW() will fail if stdout is redirected, so just fall through * to writing unconverted to the logfile in this case. * * Since we palloc the structure required for conversion, also fall @@ -1788,13 +1790,18 @@ write_console(const char *line, int len) #else /* - * Conversion on non-win32 platform is not implemented yet. It requires + * Conversion on non-win32 platforms is not implemented yet. It requires * non-throw version of pg_do_encoding_conversion(), that converts * unconvertable characters to '?' without errors. */ #endif - write(fileno(stderr), line, len); + /* + * We ignore any error from write() here. We have no useful way to report + * it ... certainly whining on stderr isn't likely to be productive. + */ + rc = write(fileno(stderr), line, len); + (void) rc; } /* @@ -2457,13 +2464,30 @@ send_message_to_server_log(ErrorData *edata) /* * Send data to the syslogger using the chunked protocol + * + * Note: when there are multiple backends writing into the syslogger pipe, + * it's critical that each write go into the pipe indivisibly, and not + * get interleaved with data from other processes. Fortunately, the POSIX + * spec requires that writes to pipes be atomic so long as they are not + * more than PIPE_BUF bytes long. So we divide long messages into chunks + * that are no more than that length, and send one chunk per write() call. + * The collector process knows how to reassemble the chunks. + * + * Because of the atomic write requirement, there are only two possible + * results from write() here: -1 for failure, or the requested number of + * bytes. There is not really anything we can do about a failure; retry would + * probably be an infinite loop, and we can't even report the error usefully. + * (There is noplace else we could send it!) So we might as well just ignore + * the result from write(). However, on some platforms you get a compiler + * warning from ignoring write()'s result, so do a little dance with casting + * rc to void to shut up the compiler. */ static void write_pipe_chunks(char *data, int len, int dest) { PipeProtoChunk p; - int fd = fileno(stderr); + int rc; Assert(len > 0); @@ -2476,7 +2500,8 @@ write_pipe_chunks(char *data, int len, int dest) p.proto.is_last = (dest == LOG_DESTINATION_CSVLOG ? 'F' : 'f'); p.proto.len = PIPE_MAX_PAYLOAD; memcpy(p.proto.data, data, PIPE_MAX_PAYLOAD); - write(fd, &p, PIPE_HEADER_SIZE + PIPE_MAX_PAYLOAD); + rc = write(fd, &p, PIPE_HEADER_SIZE + PIPE_MAX_PAYLOAD); + (void) rc; data += PIPE_MAX_PAYLOAD; len -= PIPE_MAX_PAYLOAD; } @@ -2485,7 +2510,8 @@ write_pipe_chunks(char *data, int len, int dest) p.proto.is_last = (dest == LOG_DESTINATION_CSVLOG ? 'T' : 't'); p.proto.len = len; memcpy(p.proto.data, data, len); - write(fd, &p, PIPE_HEADER_SIZE + len); + rc = write(fd, &p, PIPE_HEADER_SIZE + len); + (void) rc; } |