truncate-first-time.patch

diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index bbf725dfbc5aa58a5b43f15998e2c0424906ecfb..bfef707050a82f7842b1e2da550efcfa4882ec82 100644
*** a/src/backend/postmaster/postmaster.c
--- b/src/backend/postmaster/postmaster.c
*************** typedef struct
*** 441,446 ****
--- 441,447 ----
  	pid_t		PostmasterPid;
  	TimestampTz PgStartTime;
  	TimestampTz PgReloadTime;
+ 	pg_time_t	first_syslogger_file_time;
  	bool		redirection_done;
  	bool		IsBinaryUpgrade;
  	int			max_safe_fds;
*************** MaxLivePostmasterChildren(void)
*** 4701,4707 ****
  
  /*
   * The following need to be available to the save/restore_backend_variables
!  * functions
   */
  extern slock_t *ShmemLock;
  extern LWLock *LWLockArray;
--- 4702,4708 ----
  
  /*
   * The following need to be available to the save/restore_backend_variables
!  * functions.  They are marked NON_EXEC_STATIC in their home modules.
   */
  extern slock_t *ShmemLock;
  extern LWLock *LWLockArray;
*************** extern slock_t *ProcStructLock;
*** 4709,4714 ****
--- 4710,4716 ----
  extern PGPROC *AuxiliaryProcs;
  extern PMSignalData *PMSignalState;
  extern pgsocket pgStatSock;
+ extern pg_time_t first_syslogger_file_time;
  
  #ifndef WIN32
  #define write_inheritable_socket(dest, src, childpid) ((*(dest) = (src)), true)
*************** save_backend_variables(BackendParameters
*** 4761,4766 ****
--- 4763,4769 ----
  	param->PostmasterPid = PostmasterPid;
  	param->PgStartTime = PgStartTime;
  	param->PgReloadTime = PgReloadTime;
+ 	param->first_syslogger_file_time = first_syslogger_file_time;
  
  	param->redirection_done = redirection_done;
  	param->IsBinaryUpgrade = IsBinaryUpgrade;
*************** restore_backend_variables(BackendParamet
*** 4985,4990 ****
--- 4988,4994 ----
  	PostmasterPid = param->PostmasterPid;
  	PgStartTime = param->PgStartTime;
  	PgReloadTime = param->PgReloadTime;
+ 	first_syslogger_file_time = param->first_syslogger_file_time;
  
  	redirection_done = param->redirection_done;
  	IsBinaryUpgrade = param->IsBinaryUpgrade;
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 919cc49fa945f27642f8723fefec486cc6657478..0febf64d87f2b337b70e4c9e49d4399b6aa03c0e 100644
*** a/src/backend/postmaster/syslogger.c
--- b/src/backend/postmaster/syslogger.c
***************
*** 2,8 ****
   *
   * syslogger.c
   *
!  * The system logger (syslogger) is new in Postgres 8.0. It catches all
   * stderr output from the postmaster, backends, and other subprocesses
   * by redirecting to a pipe, and writes it to a set of logfiles.
   * It's possible to have size and age limits for the logfile configured
--- 2,8 ----
   *
   * syslogger.c
   *
!  * The system logger (syslogger) appeared in Postgres 8.0. It catches all
   * stderr output from the postmaster, backends, and other subprocesses
   * by redirecting to a pipe, and writes it to a set of logfiles.
   * It's possible to have size and age limits for the logfile configured
*************** static bool pipe_eof_seen = false;
*** 91,96 ****
--- 91,97 ----
  static bool rotation_disabled = false;
  static FILE *syslogFile = NULL;
  static FILE *csvlogFile = NULL;
+ NON_EXEC_STATIC pg_time_t first_syslogger_file_time = 0;
  static char *last_file_name = NULL;
  static char *last_csv_file_name = NULL;
  static Latch sysLoggerLatch;
*************** SysLoggerMain(int argc, char *argv[])
*** 291,296 ****
--- 292,304 ----
  		elog(FATAL, "could not create syslogger data transfer thread: %m");
  #endif   /* WIN32 */
  
+ 	/*
+ 	 * Remember active logfile's name.  We recompute this from the reference
+ 	 * time because passing down just the pg_time_t is a lot cheaper than
+ 	 * passing a whole file path in the EXEC_BACKEND case.
+ 	 */
+ 	last_file_name = logfile_getname(first_syslogger_file_time, NULL);
+ 
  	/* remember active logfile parameters */
  	currentLogDir = pstrdup(Log_directory);
  	currentLogFilename = pstrdup(Log_filename);
*************** SysLogger_Start(void)
*** 560,568 ****
  
  	/*
  	 * The initial logfile is created right in the postmaster, to verify that
! 	 * the Log_directory is writable.
  	 */
! 	filename = logfile_getname(time(NULL), NULL);
  
  	syslogFile = logfile_open(filename, "a", false);
  
--- 568,585 ----
  
  	/*
  	 * The initial logfile is created right in the postmaster, to verify that
! 	 * the Log_directory is writable.  We save the reference time so that
! 	 * the syslogger child process can recompute this file name.
! 	 *
! 	 * It might look a bit strange to re-do this during a syslogger restart,
! 	 * but we must do so since the postmaster closed syslogFile after the
! 	 * previous fork (and remembering that old file wouldn't be right anyway).
! 	 * Note we always append here, we won't overwrite any existing file.  This
! 	 * is consistent with the normal rules, because by definition this is not
! 	 * a time-based rotation.
  	 */
! 	first_syslogger_file_time = time(NULL);
! 	filename = logfile_getname(first_syslogger_file_time, NULL);
  
  	syslogFile = logfile_open(filename, "a", false);
  
*************** pipeThread(void *arg)
*** 1046,1053 ****
  #endif   /* WIN32 */
  
  /*
!  * open the csv log file - we do this opportunistically, because
   * we don't know if CSV logging will be wanted.
   */
  static void
  open_csvlogfile(void)
--- 1063,1074 ----
  #endif   /* WIN32 */
  
  /*
!  * Open the csv log file - we do this opportunistically, because
   * we don't know if CSV logging will be wanted.
+  *
+  * This is only used the first time we open the csv log in a given syslogger
+  * process, not during rotations.  As with opening the main log file, we
+  * always append in this situation.
   */
  static void
  open_csvlogfile(void)
*************** open_csvlogfile(void)
*** 1058,1064 ****
  
  	csvlogFile = logfile_open(filename, "a", false);
  
! 	pfree(filename);
  }
  
  /*
--- 1079,1088 ----
  
  	csvlogFile = logfile_open(filename, "a", false);
  
! 	if (last_csv_file_name != NULL)		/* probably shouldn't happen */
! 		pfree(last_csv_file_name);
! 
! 	last_csv_file_name = filename;
  }
  
  /*
*************** logfile_rotate(bool time_based_rotation,
*** 1137,1150 ****
  	 * elapsed time and not something else, and (c) the computed file name is
  	 * different from what we were previously logging into.
  	 *
! 	 * Note: during the first rotation after forking off from the postmaster,
! 	 * last_file_name will be NULL.  (We don't bother to set it in the
! 	 * postmaster because it ain't gonna work in the EXEC_BACKEND case.) So we
! 	 * will always append in that situation, even though truncating would
! 	 * usually be safe.
! 	 *
! 	 * For consistency, we treat CSV logs the same even though they aren't
! 	 * opened in the postmaster.
  	 */
  	if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
  	{
--- 1161,1167 ----
  	 * elapsed time and not something else, and (c) the computed file name is
  	 * different from what we were previously logging into.
  	 *
! 	 * Note: last_file_name should never be NULL here, but if it is, append.
  	 */
  	if (time_based_rotation || (size_rotation_for & LOG_DESTINATION_STDERR))
  	{