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Fixed that packed transid can be compared byte per byte and we get them in increasing order

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The old way to store the length prefix was (256 - length); This is now changed to (length -249)
Fixed also that some defines to have a MARIA_ prefix

storage/maria/ma_control_file.c:
  Added comment
storage/maria/ma_key.c:
  Added MARIA_ prefix to some defines
  Changed how packed transid length was stored
storage/maria/ma_open.c:
  Added MARIA_ prefix to some defines
storage/maria/maria_def.h:
  Added MARIA_ prefix to some defines
  Changed how packed transid length was stored
This commit is contained in:
Michael Widenius 2008-11-04 12:54:04 +02:00
parent cc684c3475
commit e4febda89e
4 changed files with 42 additions and 16 deletions
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8
storage/maria/ma_control_file.c
View file

@ -185,8 +185,12 @@ static CONTROL_FILE_ERROR create_control_file(const char *name,
files around (indeed it could be that the control file alone was deleted
or not restored, and we should not go on with life at this point).
TODO: For now we trust (this is alpha version), but for beta if would
be great to verify.
Things should still be relatively safe as if someone tries to use
an old table with a new control file the different uuid:s between
the files will cause ma_open() to generate an HA_ERR_OLD_FILE
error. When used from mysqld this will cause the table to be open
in repair mode which will remove all dependencies between the
table and the old control file.
We could have a tool which can rebuild the control file, by reading the
directory of logs, finding the newest log, reading it to find last

33
storage/maria/ma_key.c
View file

@ -61,7 +61,7 @@ static int _ma_put_key_in_record(MARIA_HA *info,uint keynr,uchar *record);
if trid < 256-12
one byte
else
one byte prefix (256-length_of_trid_in_bytes) followed by data
one byte prefix length_of_trid_in_bytes + 249 followed by data
in high-byte-first order
Prefix bytes 244 to 249 are reserved for negative transid, that can be used
@ -69,6 +69,25 @@ static int _ma_put_key_in_record(MARIA_HA *info,uint keynr,uchar *record);
We have to store transid in high-byte-first order to be able to do a
fast byte-per-byte comparision of them without packing them up.
For example, assuming we the following data:
key_data: 1 (4 byte integer)
pointer_to_row: 2 << 8 + 3 = 515 (page 2, row 3)
table_create_transid 1000 Defined at create table time
transid 1010 Transaction that created row
delete_transid 2011 Transaction that deleted row
In addition we assume the table is created with a data pointer length
of 4 bytes (this is automatically calculated based on the medium
length of rows and the given max number of rows)
The binary data for the key would then look like this in hex:
00 00 00 01 Key data (1 stored high byte first)
00 00 00 47 (515 << 1) + 1 ; The last 1 is marker that key cont.
15 ((1000-1010) << 1) + 1 ; The last 1 is marker that key cont.
FB 07 E6 length byte and ((2011 - 1000) << 1) = 07 E6
*/
uint transid_store_packed(MARIA_HA *info, uchar *to, ulonglong trid)
@ -76,7 +95,7 @@ uint transid_store_packed(MARIA_HA *info, uchar *to, ulonglong trid)
uchar *start;
uint length;
uchar buff[8];
DBUG_ASSERT(trid < (LL(1) << (MAX_PACK_TRANSID_SIZE*8)));
DBUG_ASSERT(trid < (LL(1) << (MARIA_MAX_PACK_TRANSID_SIZE*8)));
DBUG_ASSERT(trid >= info->s->state.create_trid);
trid= (trid - info->s->state.create_trid) << 1;
@ -84,7 +103,7 @@ uint transid_store_packed(MARIA_HA *info, uchar *to, ulonglong trid)
/* Mark that key contains transid */
to[-1]|= 1;
if (trid < MIN_TRANSID_PACK_PREFIX)
if (trid < MARIA_MIN_TRANSID_PACK_OFFSET)
{
to[0]= (uchar) trid;
return 1;
@ -100,7 +119,8 @@ uint transid_store_packed(MARIA_HA *info, uchar *to, ulonglong trid)
} while (trid);
length= (uint) (to - buff);
start[0]= (uchar) (256 - length); /* Store length prefix */
/* Store length prefix */
start[0]= (uchar) (length + MARIA_TRANSID_PACK_OFFSET);
start++;
/* Copy things in high-byte-first order to output buffer */
do
@ -127,12 +147,13 @@ ulonglong transid_get_packed(MARIA_SHARE *share, const uchar *from)
ulonglong value;
uint length;
if (from[0] < MIN_TRANSID_PACK_PREFIX)
if (from[0] < MARIA_MIN_TRANSID_PACK_OFFSET)
value= (ulonglong) from[0];
else
{
value= 0;
for (length= (uint) (256 - from[0]), value= (ulonglong) from[1], from+=2;
for (length= (uint) (from[0] - MARIA_TRANSID_PACK_OFFSET),
value= (ulonglong) from[1], from+=2;
--length ;
from++)
value= (value << 8) + ((ulonglong) *from);

2
storage/maria/ma_open.c
View file

@ -449,7 +449,7 @@ MARIA_HA *maria_open(const char *name, int mode, uint open_flags)
/* Ensure we have space in the key buffer for transaction id's */
if (share->base.born_transactional)
share->base.max_key_length= ALIGN_SIZE(share->base.max_key_length +
MAX_PACK_TRANSID_SIZE);
MARIA_MAX_PACK_TRANSID_SIZE);
/*
If page cache is not initialized, then assume we will create the

15
storage/maria/maria_def.h
View file

@ -146,14 +146,15 @@ typedef struct st_maria_state_info
#define MARIA_KEYDEF_SIZE (2+ 5*2)
#define MARIA_UNIQUEDEF_SIZE (2+1+1)
#define HA_KEYSEG_SIZE (6+ 2*2 + 4*2)
#define MARIA_MAX_KEY_BUFF (HA_MAX_KEY_BUFF + MAX_PACK_TRANSID_SIZE)
#define MARIA_MAX_KEY_BUFF (HA_MAX_KEY_BUFF + MARIA_MAX_PACK_TRANSID_SIZE)
#define MARIA_COLUMNDEF_SIZE (2*7+1+1+4)
#define MARIA_BASE_INFO_SIZE (MY_UUID_SIZE + 5*8 + 6*4 + 11*2 + 6 + 5*2 + 1 + 16)
#define MARIA_INDEX_BLOCK_MARGIN 16 /* Safety margin for .MYI tables */
/* Internal management bytes needed to store 2 keys on an index page */
#define MAX_PACK_TRANSID_SIZE (TRANSID_SIZE+1)
#define MIN_TRANSID_PACK_PREFIX (256-TRANSID_SIZE*2)
#define MARIA_INDEX_OVERHEAD_SIZE (MAX_PACK_TRANSID_SIZE * 2)
/* Internal management bytes needed to store 2 transid/key on an index page */
#define MARIA_MAX_PACK_TRANSID_SIZE (TRANSID_SIZE+1)
#define MARIA_TRANSID_PACK_OFFSET (256- TRANSID_SIZE - 1)
#define MARIA_MIN_TRANSID_PACK_OFFSET (MARIA_TRANSID_PACK_OFFSET-TRANSID_SIZE)
#define MARIA_INDEX_OVERHEAD_SIZE (MARIA_MAX_PACK_TRANSID_SIZE * 2)
#define MARIA_DELETE_KEY_NR 255 /* keynr for deleted blocks */
/*
@ -941,8 +942,8 @@ extern my_bool _ma_compact_keypage(MARIA_HA *info, MARIA_KEYDEF *keyinfo,
extern uint transid_store_packed(MARIA_HA *info, uchar *to, ulonglong trid);
extern ulonglong transid_get_packed(MARIA_SHARE *share, const uchar *from);
#define transid_packed_length(data) \
((data)[0] < MIN_TRANSID_PACK_PREFIX ? 1 : \
(uint) (257 - (uchar) (data)[0]))
((data)[0] < MARIA_MIN_TRANSID_PACK_OFFSET ? 1 : \
(uint) ((uchar) (data)[0]) - (MARIA_TRANSID_PACK_OFFSET - 1))
#define key_has_transid(key) (*(key) & 1)
extern MARIA_KEY *_ma_make_key(MARIA_HA *info, MARIA_KEY *int_key, uint keynr,