Reduce unnecessary PANIC to ERROR, improve a couple of comments.

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 6a656a3dbbd9bef429e0af8c762bbd09b0e8283a..42a4befba1ea04d69edb39bc16f7366056f33bf7 100644 (file)
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.309 2008/05/14 14:02:57 mha Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.310 2008/05/16 19:15:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -67,6 +67,7 @@ bool          XLogArchiveMode = false;
 char      *XLogArchiveCommand = NULL;
 bool           fullPageWrites = true;
 bool           log_checkpoints = false;
+int            sync_method = DEFAULT_SYNC_METHOD;
 
 #ifdef WAL_DEBUG
 bool           XLOG_DEBUG = false;
@@ -88,8 +89,6 @@ bool          XLOG_DEBUG = false;
 /*
  * GUC support
  */
-int            sync_method = DEFAULT_SYNC_METHOD;
-
 const struct config_enum_entry sync_method_options[] = {
        {"fsync", SYNC_METHOD_FSYNC},
 #ifdef HAVE_FSYNC_WRITETHROUGH
@@ -1613,7 +1612,8 @@ XLogWrite(XLogwrtRqst WriteRqst, bool flexible, bool xlog_switch)
                 * have no open file or the wrong one.  However, we do not need to
                 * fsync more than one file.
                 */
-               if (sync_method != SYNC_METHOD_OPEN && sync_method != SYNC_METHOD_OPEN_DSYNC)
+               if (sync_method != SYNC_METHOD_OPEN &&
+                       sync_method != SYNC_METHOD_OPEN_DSYNC)
                {
                        if (openLogFile >= 0 &&
                                !XLByteInPrevSeg(LogwrtResult.Write, openLogId, openLogSeg))
@@ -6340,10 +6340,10 @@ get_sync_bit(int method)
        switch (method)
        {
                /*
-                * Values for these sync options are defined even if they are not
-                * supported on the current platform. They are not included in
-                * the enum option array, and therefor will never be set if the
-                * platform doesn't support it.
+                * enum values for all sync options are defined even if they are not
+                * supported on the current platform.  But if not, they are not
+                * included in the enum option array, and therefore will never be seen
+                * here.
                 */
                case SYNC_METHOD_FSYNC:
                case SYNC_METHOD_FSYNC_WRITETHROUGH:
@@ -6358,12 +6358,8 @@ get_sync_bit(int method)
                        return OPEN_DATASYNC_FLAG;
 #endif
                default:
-                       /* 
-                        * This "can never happen", since the available values in
-                        * new_sync_method are controlled by the available enum
-                        * options.
-                        */
-                       elog(PANIC, "unrecognized wal_sync_method: %d", method);
+                       /* can't happen (unless we are out of sync with option array) */
+                       elog(ERROR, "unrecognized wal_sync_method: %d", method);
                        return 0; /* silence warning */
        }
 }
@@ -6392,7 +6388,7 @@ assign_xlog_sync_method(int new_sync_method, bool doit, GucSource source)
                                                (errcode_for_file_access(),
                                                 errmsg("could not fsync log file %u, segment %u: %m",
                                                                openLogId, openLogSeg)));
-                       if (get_sync_bit(sync_method)  != get_sync_bit(new_sync_method))
+                       if (get_sync_bit(sync_method) != get_sync_bit(new_sync_method))
                                XLogFileClose();
                }
        }