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MDEV-9021: MYSQLD SEGFAULTS WHEN BUILT USING --WITH-MAX-INDEXES=128

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The bitmap implementation defines two template Bitmap classes. One
optimized for 64-bit (default) wide bitmaps while the other is used for
all other widths.

In order to optimize the computations, Bitmap<64> class has defined its
own member functions for bitmap operations, the other one, however,
relies on mysys' bitmap implementation (mysys/my_bitmap.c).

Issue 1:
In case of non 64-bit Bitmap class, intersect() wrongly reset the
received bitmap while initialising a new local bitmap structure
(bitmap_init() clears the bitmap buffer) thus, the received bitmap was
getting cleared.

Fixed by initializing the local bitmap structure by using a temporary
buffer and later copying the received bitmap to the initialised bitmap
structure.

Issue 2:
The non 64-bit Bitmap class had the Iterator missing which caused
compilation failure.

Also added a cmake variable to hold the MAX_INDEXES value when supplied
from the command prompt. (eg. cmake .. -DMAX_INDEXES=128U). Checks have
been put in place to trigger build failure if MAX_INDEXES value is
greater than 128.

Test modifications:
* Introduced include/have_max_indexes_[64|128].inc to facilitate
skipping of tests for which the output differs with different
MAX_INDEXES.

* Introduced include/max_indexes.inc which would get modified by cmake
to reflect the MAX_INDEXES value used to build the server. This file
simply sets an mtr variable '$max_indexes' to show the MAX_INDEXES
value, which will then be consumed by the above introduced include file.

* Some tests (portions), dependent on MAX_INDEXES value, have been moved
to separate test files.
This commit is contained in:
Nirbhay Choubey
2015-11-06 14:38:03 -05:00
parent d6b430c91b
commit 7ec6558503
28 changed files with 3079 additions and 1157 deletions
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44
sql/sql_bitmap.h
View File

@ -51,8 +51,27 @@ public:
void intersect(Bitmap& map2) { bitmap_intersect(&map, &map2.map); }
void intersect(ulonglong map2buff)
{
// Use a spearate temporary buffer, as bitmap_init() clears all the bits.
ulonglong buf2;
MY_BITMAP map2;
my_bitmap_init(&map2, (uint32 *)&map2buff, sizeof(ulonglong)*8, 0);
my_bitmap_init(&map2, (uint32 *) &buf2, sizeof(ulonglong) * 8, 0);
// Store the original bits.
if (sizeof(ulonglong) >= 8)
{
int8store(const_cast<uchar *>(static_cast<uchar *>
(static_cast<void *>(&buf2))),
map2buff);
}
else
{
DBUG_ASSERT(sizeof(buffer) >= 4);
int4store(const_cast<uchar *>(static_cast<uchar *>
(static_cast<void *>(&buf2))),
static_cast<uint32>(map2buff));
}
bitmap_intersect(&map, &map2);
}
/* Use highest bit for all bits above sizeof(ulonglong)*8. */
@ -93,14 +112,33 @@ public:
ulonglong to_ulonglong() const
{
if (sizeof(buffer) >= 8)
return uint8korr(buffer);
return uint8korr(static_cast<const uchar *>
(static_cast<const void *>(buffer)));
DBUG_ASSERT(sizeof(buffer) >= 4);
return (ulonglong) uint4korr(buffer);
return (ulonglong)
uint4korr(static_cast<const uchar *>
(static_cast<const void *>(buffer)));
}
uint bits_set()
{
return bitmap_bits_set(&map);
}
class Iterator
{
Bitmap &map;
uint no;
public:
Iterator(Bitmap<default_width> &map2): map(map2), no(0) {}
int operator++(int) {
if (no == default_width) return BITMAP_END;
while (!map.is_set(no))
{
if ((++no) == default_width) return BITMAP_END;
}
return no ++;
}
enum { BITMAP_END= default_width };
};
};
/* An iterator to quickly walk over bits in unlonglong bitmap. */