A new option for maria_chk: --zerofill-keep-lsn. This will be used

by ma_test_recovery.pl when it happens that Recovery does not recreate
pages exactly as they were at first run: this option will help us
verify that the differences are in unimportant page pieces (those pieces
will be zeroed by --zerofill-keep-lsn, but not the important LSNs).


include/myisamchk.h:
  new zerofill flag for maria_chk
storage/maria/ma_check.c:
  If T_ZEROFILL_KEEP_LSN, we don't zero out LSNs of data/index pages.
  Then the table is not movable. We still mark it zerofilled, it helps
  to know what was last done to the table.
storage/maria/maria_chk.c:
  New option --zerofill-keep-lsn

2 files changed, 45 insertions, 13 deletions

diff --git a/storage/maria/ma_check.c b/storage/maria/ma_check.c
index b9873b37db5..7921af857be 100644
--- a/storage/maria/ma_check.c
+++ b/storage/maria/ma_check.c
@@ -2952,7 +2952,8 @@ static my_bool maria_zerofill_index(HA_CHECK *param, MARIA_HA *info,
   my_off_t pos;
   my_off_t key_file_length= share->state.state.key_file_length;
   uint block_size= share->block_size;
-  my_bool transactional= share->base.born_transactional;
+  my_bool zero_lsn= share->base.born_transactional &&
+    !(param->testflag & T_ZEROFILL_KEEP_LSN);
   DBUG_ENTER("maria_zerofill_index");
 
   if (!(param->testflag & T_SILENT))
@@ -2979,7 +2980,7 @@ static my_bool maria_zerofill_index(HA_CHECK *param, MARIA_HA *info,
                             llstr(pos, llbuff), my_errno);
       DBUG_RETURN(1);
     }
-    if (transactional)
+    if (zero_lsn)
       bzero(buff, LSN_SIZE);
     length= _ma_get_page_used(share, buff);
     /* Skip mailformed blocks */
@@ -3021,6 +3022,7 @@ static my_bool maria_zerofill_data(HA_CHECK *param, MARIA_HA *info,
   pgcache_page_no_t page;
   uint block_size= share->block_size;
   MARIA_FILE_BITMAP *bitmap= &share->bitmap;
+  my_bool zero_lsn= !(param->testflag & T_ZEROFILL_KEEP_LSN);
   DBUG_ENTER("maria_zerofill_data");
 
   /* This works only with BLOCK_RECORD files */
@@ -3055,16 +3057,23 @@ static my_bool maria_zerofill_data(HA_CHECK *param, MARIA_HA *info,
     page_type= buff[PAGE_TYPE_OFFSET] & PAGE_TYPE_MASK;
     switch ((enum en_page_type) page_type) {
     case UNALLOCATED_PAGE:
-      bzero(buff, block_size);
+      if (zero_lsn)
+        bzero(buff, block_size);
+      else
+        bzero(buff + LSN_SIZE, block_size - LSN_SIZE);
       break;
     case BLOB_PAGE:
       if (_ma_bitmap_get_page_bits(info, bitmap, page) == 0)
       {
         /* Unallocated page */
-        bzero(buff, block_size);
+        if (zero_lsn)
+          bzero(buff, block_size);
+        else
+          bzero(buff + LSN_SIZE, block_size - LSN_SIZE);
       }
       else
-        bzero(buff, LSN_SIZE);
+        if (zero_lsn)
+          bzero(buff, LSN_SIZE);
       break;
     case HEAD_PAGE:
     case TAIL_PAGE:
@@ -3073,7 +3082,8 @@ static my_bool maria_zerofill_data(HA_CHECK *param, MARIA_HA *info,
       uint offset, dir_start;
       uchar *dir;
 
-      bzero(buff, LSN_SIZE);
+      if (zero_lsn)
+        bzero(buff, LSN_SIZE);
       if (max_entry != 0)
       {
         dir= dir_entry_pos(buff, block_size, max_entry - 1);
@@ -3123,7 +3133,8 @@ err:
 
 int maria_zerofill(HA_CHECK *param, MARIA_HA *info, const char *name)
 {
-  my_bool error, reenable_logging;
+  my_bool error, reenable_logging,
+    zero_lsn= !(param->testflag & T_ZEROFILL_KEEP_LSN);
   DBUG_ENTER("maria_zerofill");
   if ((reenable_logging= info->s->now_transactional))
     _ma_tmp_disable_logging_for_table(info, 0);
@@ -3132,11 +3143,12 @@ int maria_zerofill(HA_CHECK *param, MARIA_HA *info, const char *name)
                 _ma_set_uuid(info, 0))))
   {
     /*
-      Mark that table is movable and that we have done zerofill of data and
-      index
+      Mark that we have done zerofill of data and index. If we zeroed pages'
+      LSN, table is movable.
     */
-    info->s->state.changed&= ~(STATE_NOT_ZEROFILLED | STATE_NOT_MOVABLE |
-                               STATE_MOVED);
+    info->s->state.changed&= ~STATE_NOT_ZEROFILLED;
+    if (zero_lsn)
+      info->s->state.changed&= ~(STATE_NOT_MOVABLE | STATE_MOVED);
     /* Ensure state are flushed to disk */
     info->update= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
   }
diff --git a/storage/maria/maria_chk.c b/storage/maria/maria_chk.c
index 69d833e49fb..e51a243a5a0 100644
--- a/storage/maria/maria_chk.c
+++ b/storage/maria/maria_chk.c
@@ -183,7 +183,7 @@ enum options_mc {
   OPT_SORT_KEY_BLOCKS, OPT_DECODE_BITS, OPT_FT_MIN_WORD_LEN,
   OPT_FT_MAX_WORD_LEN, OPT_FT_STOPWORD_FILE,
   OPT_MAX_RECORD_LENGTH, OPT_AUTO_CLOSE, OPT_STATS_METHOD, OPT_TRANSACTION_LOG,
-  OPT_SKIP_SAFEMALLOC
+  OPT_SKIP_SAFEMALLOC, OPT_ZEROFILL_KEEP_LSN
 };
 
 static struct my_option my_long_options[] =
@@ -375,6 +375,12 @@ static struct my_option my_long_options[] =
   { "zerofill", 'z',
     "Fill empty space in data and index files with zeroes",
     0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
+#ifdef IDENTICAL_PAGES_AFTER_RECOVERY
+  { "zerofill-keep-lsn", OPT_ZEROFILL_KEEP_LSN,
+    "Like --zerofill but does not zero out LSN of data/index pages;"
+    " used only for testing and debugging",
+#endif
+    0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0},
   { 0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
 };
 
@@ -505,7 +511,13 @@ static void usage(void)
 		      (It may be VERY slow to do a sort the first time!).\n\
   -b,  --block-search=#\n\
                       Find a record, a block at given offset belongs to.\n\
-  -z,  --zerofill     Fill empty space in data and index files with zeroes.");
+  -z,  --zerofill     Fill empty space in data and index files with zeroes"
+#ifdef IDENTICAL_PAGES_AFTER_RECOVERY
+"\n\
+  --zerofill-keep-lsn Like --zerofill but does not zero out LSN of\n\
+                      data/index pages; used only for testing and debugging"
+#endif
+       ".");
 
   print_defaults("my", load_default_groups);
   my_print_variables(my_long_options);
@@ -778,6 +790,14 @@ get_one_option(int optid,
     else
       check_param.testflag|= T_ZEROFILL;
     break;
+#ifdef IDENTICAL_PAGES_AFTER_RECOVERY
+  case OPT_ZEROFILL_KEEP_LSN:
+    if (argument == disabled_my_option)
+      check_param.testflag&= ~(T_ZEROFILL_KEEP_LSN | T_ZEROFILL);
+    else
+      check_param.testflag|= (T_ZEROFILL_KEEP_LSN | T_ZEROFILL);
+    break;
+#endif
   case 'H':
     my_print_help(my_long_options);
     exit(0);