bk commit into 4.1 tree (svoj:1.2502) BUG#17917

[Sergey Vojtovich]

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ChangeSet
  1.2502 06/04/11 19:37:16 svoj@april.(none) +1 -0
  BUG#17917 - SELECT from compressed MyISAM table crashes MySQL server
  
  Retrieving data from compressed MyISAM table which is bigger than 4G on 32-bit box
  with mmap() support results in server crash.
  
  mmap() accepts length of bytes to be mapped in second param, which is 32-bit
  size_t. But we pass data_file_length, which is 64-bit my_off_t. As a result only
  first data_file_length % 4G were mapped.
  
  Also, according to FreeBSD manual, this parameter is limited to 2Gb.
  
  This fix adds additional condition for mmap() usage, that is use mmap() for
  compressed table which size is no more than 2G.

  myisam/mi_extra.c
    1.43 06/04/11 19:37:13 svoj@april.(none) +2 -1
    Use mmap() for comressed table which size is no more than 2G.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	svoj
# Host:	april.(none)
# Root:	/home/svoj/devel/mysql/BUG17917/mysql-4.1

--- 1.42/myisam/mi_extra.c	2005-08-31 22:08:52 +05:00
+++ 1.43/myisam/mi_extra.c	2006-04-11 19:37:13 +05:00
@@ -94,7 +94,8 @@
       break;
     }
 #if defined(HAVE_MMAP) && defined(HAVE_MADVISE)
-    if ((share->options & HA_OPTION_COMPRESS_RECORD))
+    if ((share->options & HA_OPTION_COMPRESS_RECORD) &&
+        share->state.state.data_file_length <= 2147483647)
     {
       pthread_mutex_lock(&share->intern_lock);
       if (_mi_memmap_file(info))