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mariadb/storage/myisam/mi_key.c
Igor Babaev 658128af43 MDEV-16188 Use in-memory PK filters built from range index scans 
This patch contains a full implementation of the optimization
that allows to use in-memory rowid / primary filters built for range  
conditions over indexes. In many cases usage of such filters reduce  
the number of disk seeks spent for fetching table rows.

In this implementation the choice of what possible filter to be applied  
(if any) is made purely on cost-based considerations.

This implementation re-achitectured the partial implementation of
the feature pushed by Galina Shalygina in the commit
8d5a11122c.

Besides this patch contains a better implementation of the generic  
handler function handler::multi_range_read_info_const() that
takes into account gaps between ranges when calculating the cost of
range index scans. It also contains some corrections of the
implementation of the handler function records_in_range() for MyISAM.

This patch supports the feature for InnoDB and MyISAM.
2019-02-03 14:56:12 -08:00

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/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/* Functions to handle keys */
#include "myisamdef.h"
#include "m_ctype.h"
#include "sp_defs.h"
#ifdef HAVE_IEEEFP_H
#include <ieeefp.h>
#endif
#define CHECK_KEYS /* Enable safety checks */
#define FIX_LENGTH(cs, pos, length, char_length) \
do { \
if (length > char_length) \
char_length= my_charpos(cs, pos, pos+length, char_length); \
set_if_smaller(char_length,length); \
} while(0)
static int _mi_put_key_in_record(MI_INFO *info,uint keynr,
my_bool unpack_blobs, uchar *record);
/*
Make a intern key from a record
SYNOPSIS
_mi_make_key()
info MyiSAM handler
keynr key number
key Store created key here
record Record
filepos Position to record in the data file
RETURN
Length of key
*/
uint _mi_make_key(register MI_INFO *info, uint keynr, uchar *key,
const uchar *record, my_off_t filepos)
{
uchar *pos;
uchar *start;
reg1 HA_KEYSEG *keyseg;
my_bool is_ft= info->s->keyinfo[keynr].flag & HA_FULLTEXT;
DBUG_ENTER("_mi_make_key");
if (info->s->keyinfo[keynr].flag & HA_SPATIAL)
{
/*
TODO: nulls processing
*/
#ifdef HAVE_SPATIAL
DBUG_RETURN(sp_make_key(info,keynr,key,record,filepos));
#else
DBUG_ASSERT(0); /* mi_open should check that this never happens*/
#endif
}
start=key;
for (keyseg=info->s->keyinfo[keynr].seg ; keyseg->type ;keyseg++)
{
enum ha_base_keytype type=(enum ha_base_keytype) keyseg->type;
size_t length=keyseg->length;
size_t char_length;
CHARSET_INFO *cs=keyseg->charset;
if (keyseg->null_bit)
{
if (record[keyseg->null_pos] & keyseg->null_bit)
{
*key++= 0; /* NULL in key */
continue;
}
*key++=1; /* Not NULL */
}
char_length= ((!is_ft && cs && cs->mbmaxlen > 1) ? length/cs->mbmaxlen :
length);
pos= (uchar*) record+keyseg->start;
if (type == HA_KEYTYPE_BIT)
{
if (keyseg->bit_length)
{
uchar bits= get_rec_bits((uchar*) record + keyseg->bit_pos,
keyseg->bit_start, keyseg->bit_length);
*key++= bits;
length--;
}
memcpy((uchar*) key, pos, length);
key+= length;
continue;
}
if (keyseg->flag & HA_SPACE_PACK)
{
if (type != HA_KEYTYPE_NUM)
{
length= cs->cset->lengthsp(cs, (char*) pos, length);
}
else
{
uchar *end= pos + length;
while (pos < end && pos[0] == ' ')
pos++;
length=(size_t) (end-pos);
}
FIX_LENGTH(cs, pos, length, char_length);
store_key_length_inc(key,char_length);
memcpy(key, pos,char_length);
key+=char_length;
continue;
}
if (keyseg->flag & HA_VAR_LENGTH_PART)
{
uint pack_length= (keyseg->bit_start == 1 ? 1 : 2);
uint tmp_length= (pack_length == 1 ? (uint) *(uchar*) pos :
uint2korr(pos));
pos+= pack_length; /* Skip VARCHAR length */
set_if_smaller(length,tmp_length);
FIX_LENGTH(cs, pos, length, char_length);
store_key_length_inc(key,char_length);
memcpy(key, pos, char_length);
key+= char_length;
continue;
}
else if (keyseg->flag & HA_BLOB_PART)
{
uint tmp_length=_mi_calc_blob_length(keyseg->bit_start,pos);
memcpy(&pos,pos+keyseg->bit_start,sizeof(char*));
set_if_smaller(length,tmp_length);
FIX_LENGTH(cs, pos, length, char_length);
store_key_length_inc(key,char_length);
memcpy(key, pos, char_length);
key+= char_length;
continue;
}
else if (keyseg->flag & HA_SWAP_KEY)
{ /* Numerical column */
if (type == HA_KEYTYPE_FLOAT)
{
float nr;
float4get(nr,pos);
if (isnan(nr))
{
/* Replace NAN with zero */
bzero(key,length);
key+=length;
continue;
}
}
else if (type == HA_KEYTYPE_DOUBLE)
{
double nr;
float8get(nr,pos);
if (isnan(nr))
{
bzero(key,length);
key+=length;
continue;
}
}
pos+=length;
while (length--)
{
*key++ = *--pos;
}
continue;
}
FIX_LENGTH(cs, pos, length, char_length);
memcpy((uchar*) key, pos, char_length);
if (length > char_length)
cs->cset->fill(cs, (char*) key+char_length, length-char_length, ' ');
key+= length;
}
_mi_dpointer(info,key,filepos);
DBUG_PRINT("exit",("keynr: %d",keynr));
DBUG_DUMP("key",(uchar*) start,(uint) (key-start)+keyseg->length);
DBUG_EXECUTE("key",
_mi_print_key(DBUG_FILE,info->s->keyinfo[keynr].seg,start,
(uint) (key-start)););
DBUG_RETURN((uint) (key-start)); /* Return keylength */
} /* _mi_make_key */
/*
Pack a key to intern format from given format (c_rkey)
SYNOPSIS
_mi_pack_key()
info MyISAM handler
uint keynr key number
key Store packed key here
old Not packed key
keypart_map bitmap of used keyparts
last_used_keyseg out parameter. May be NULL
RETURN
length of packed key
last_use_keyseg Store pointer to the keyseg after the last used one
*/
uint _mi_pack_key(register MI_INFO *info, uint keynr, uchar *key, uchar *old,
key_part_map keypart_map, HA_KEYSEG **last_used_keyseg)
{
uchar *start_key=key;
HA_KEYSEG *keyseg;
my_bool is_ft= info->s->keyinfo[keynr].flag & HA_FULLTEXT;
DBUG_ENTER("_mi_pack_key");
/* "one part" rtree key is 2*SPDIMS part key in MyISAM */
if (info->s->keyinfo[keynr].key_alg == HA_KEY_ALG_RTREE)
keypart_map= (((key_part_map)1) << (2*SPDIMS)) - 1;
/* only key prefixes are supported */
DBUG_ASSERT(((keypart_map+1) & keypart_map) == 0);
for (keyseg= info->s->keyinfo[keynr].seg ; keyseg->type && keypart_map;
old+= keyseg->length, keyseg++)
{
enum ha_base_keytype type= (enum ha_base_keytype) keyseg->type;
size_t length= keyseg->length;
size_t char_length;
uchar *pos;
CHARSET_INFO *cs=keyseg->charset;
keypart_map>>= 1;
if (keyseg->null_bit)
{
if (!(*key++= (char) 1-*old++)) /* Copy null marker */
{
if (keyseg->flag & (HA_VAR_LENGTH_PART | HA_BLOB_PART))
old+= 2;
continue; /* Found NULL */
}
}
char_length= (!is_ft && cs && cs->mbmaxlen > 1) ? length/cs->mbmaxlen : length;
pos=old;
if (keyseg->flag & HA_SPACE_PACK)
{
if (type == HA_KEYTYPE_NUM)
{
uchar *end= pos + length;
while (pos < end && pos[0] == ' ')
pos++;
length= (size_t)(end - pos);
}
else if (type != HA_KEYTYPE_BINARY)
{
length= cs->cset->lengthsp(cs, (char*) pos, length);
}
FIX_LENGTH(cs, pos, length, char_length);
store_key_length_inc(key,char_length);
memcpy(key,pos,char_length);
key+= char_length;
continue;
}
else if (keyseg->flag & (HA_VAR_LENGTH_PART | HA_BLOB_PART))
{
/* Length of key-part used with mi_rkey() always 2 */
uint tmp_length=uint2korr(pos);
pos+=2;
set_if_smaller(length,tmp_length); /* Safety */
FIX_LENGTH(cs, pos, length, char_length);
store_key_length_inc(key,char_length);
old+=2; /* Skip length */
memcpy(key, pos, char_length);
key+= char_length;
continue;
}
else if (keyseg->flag & HA_SWAP_KEY)
{ /* Numerical column */
pos+=length;
while (length--)
*key++ = *--pos;
continue;
}
FIX_LENGTH(cs, pos, length, char_length);
memcpy((uchar*) key, pos, char_length);
if (length > char_length)
cs->cset->fill(cs, (char*) key+char_length, length-char_length, ' ');
key+= length;
}
if (last_used_keyseg)
*last_used_keyseg= keyseg;
DBUG_RETURN((uint) (key-start_key));
} /* _mi_pack_key */
/*
Store found key in record
SYNOPSIS
_mi_put_key_in_record()
info MyISAM handler
keynr Key number that was used
unpack_blobs TRUE <=> Unpack blob columns
FALSE <=> Skip them. This is used by index condition
pushdown check function
record Store key here
Last read key is in info->lastkey
NOTES
Used when only-keyread is wanted
RETURN
0 ok
1 error
*/
static int _mi_put_key_in_record(register MI_INFO *info, uint keynr,
my_bool unpack_blobs, uchar *record)
{
reg2 uchar *key;
uchar *pos,*key_end;
reg1 HA_KEYSEG *keyseg;
uchar *blob_ptr;
DBUG_ENTER("_mi_put_key_in_record");
blob_ptr= (uchar*) info->lastkey2; /* Place to put blob parts */
key=(uchar*) info->lastkey; /* KEy that was read */
key_end=key+info->lastkey_length;
for (keyseg=info->s->keyinfo[keynr].seg ; keyseg->type ;keyseg++)
{
if (keyseg->null_bit)
{
if (!*key++)
{
record[keyseg->null_pos]|= keyseg->null_bit;
continue;
}
record[keyseg->null_pos]&= ~keyseg->null_bit;
}
if (keyseg->type == HA_KEYTYPE_BIT)
{
uint length= keyseg->length;
if (keyseg->bit_length)
{
uchar bits= *key++;
set_rec_bits(bits, record + keyseg->bit_pos, keyseg->bit_start,
keyseg->bit_length);
length--;
}
else
{
clr_rec_bits(record + keyseg->bit_pos, keyseg->bit_start,
keyseg->bit_length);
}
memcpy(record + keyseg->start, (uchar*) key, length);
key+= length;
continue;
}
if (keyseg->flag & HA_SPACE_PACK)
{
uint length;
get_key_length(length,key);
#ifdef CHECK_KEYS
if (length > keyseg->length || key+length > key_end)
goto err;
#endif
pos= record+keyseg->start;
if (keyseg->type != (int) HA_KEYTYPE_NUM)
{
memcpy(pos,key,(size_t) length);
keyseg->charset->cset->fill(keyseg->charset,
(char*) pos + length,
keyseg->length - length,
' ');
}
else
{
bfill(pos,keyseg->length-length,' ');
memcpy(pos+keyseg->length-length,key,(size_t) length);
}
key+=length;
continue;
}
if (keyseg->flag & HA_VAR_LENGTH_PART)
{
uint length;
get_key_length(length,key);
#ifdef CHECK_KEYS
if (length > keyseg->length || key+length > key_end)
goto err;
#endif
/* Store key length */
if (keyseg->bit_start == 1)
*(uchar*) (record+keyseg->start)= (uchar) length;
else
int2store(record+keyseg->start, length);
/* And key data */
memcpy(record+keyseg->start + keyseg->bit_start, (uchar*) key, length);
key+= length;
}
else if (keyseg->flag & HA_BLOB_PART)
{
uint length;
get_key_length(length,key);
#ifdef CHECK_KEYS
if (length > keyseg->length || key+length > key_end)
goto err;
#endif
if (unpack_blobs)
{
memcpy(record+keyseg->start+keyseg->bit_start,
&blob_ptr, sizeof(char *));
memcpy(blob_ptr,key,length);
blob_ptr+=length;
/* The above changed info->lastkey2. Inform mi_rnext_same(). */
info->update&= ~HA_STATE_RNEXT_SAME;
_mi_store_blob_length(record+keyseg->start,
(uint) keyseg->bit_start,length);
}
key+=length;
}
else if (keyseg->flag & HA_SWAP_KEY)
{
uchar *to= record+keyseg->start+keyseg->length;
uchar *end= key+keyseg->length;
#ifdef CHECK_KEYS
if (end > key_end)
goto err;
#endif
do
{
*--to= *key++;
} while (key != end);
continue;
}
else
{
#ifdef CHECK_KEYS
if (key+keyseg->length > key_end)
goto err;
#endif
memcpy(record+keyseg->start,(uchar*) key,
(size_t) keyseg->length);
key+= keyseg->length;
}
}
DBUG_RETURN(0);
err:
DBUG_RETURN(1); /* Crashed row */
} /* _mi_put_key_in_record */
/* Here when key reads are used */
int _mi_read_key_record(MI_INFO *info, my_off_t filepos, uchar *buf)
{
fast_mi_writeinfo(info);
if (filepos != HA_OFFSET_ERROR)
{
if (info->lastinx >= 0)
{ /* Read only key */
if (_mi_put_key_in_record(info,(uint) info->lastinx, TRUE, buf))
{
mi_print_error(info->s, HA_ERR_CRASHED);
my_errno=HA_ERR_CRASHED;
return -1;
}
info->update|= HA_STATE_AKTIV; /* We should find a record */
return 0;
}
my_errno=HA_ERR_WRONG_INDEX;
}
return(-1); /* Wrong data to read */
}
/*
Save current key tuple to record and call index condition check function
SYNOPSIS
mi_check_index_cond()
info MyISAM handler
keynr Index we're running a scan on
record Record buffer to use (it is assumed that index check function
will look for column values there)
RETURN
ICP_ERROR Error
ICP_NO_MATCH Index condition is not satisfied, continue scanning
ICP_MATCH Index condition is satisfied
ICP_OUT_OF_RANGE Index condition is not satisfied, end the scan.
*/
ICP_RESULT mi_check_index_cond(register MI_INFO *info, uint keynr,
uchar *record)
{
ICP_RESULT res;
if (_mi_put_key_in_record(info, keynr, FALSE, record))
{
/* Impossible case; Can only happen if bug in code */
mi_print_error(info->s, HA_ERR_CRASHED);
info->lastpos= HA_OFFSET_ERROR; /* No active record */
my_errno= HA_ERR_CRASHED;
res= ICP_ERROR;
}
else if ((res= info->index_cond_func(info->index_cond_func_arg)) ==
ICP_OUT_OF_RANGE)
{
/* We got beyond the end of scanned range */
info->lastpos= HA_OFFSET_ERROR; /* No active record */
my_errno= HA_ERR_END_OF_FILE;
}
return res;
}
int mi_check_rowid_filter(MI_INFO *info)
{
return info->rowid_filter_func(info->rowid_filter_func_arg);
}
int mi_check_rowid_filter_is_active(MI_INFO *info)
{
if (info->rowid_filter_is_active_func == NULL)
return 0;
return info->rowid_filter_is_active_func(info->rowid_filter_func_arg);
}
/*
Retrieve auto_increment info
SYNOPSIS
retrieve_auto_increment()
info MyISAM handler
record Row to update
IMPLEMENTATION
For signed columns we don't retrieve the auto increment value if it's
less than zero.
*/
ulonglong retrieve_auto_increment(MI_INFO *info,const uchar *record)
{
ulonglong value= 0; /* Store unsigned values here */
longlong s_value= 0; /* Store signed values here */
HA_KEYSEG *keyseg= info->s->keyinfo[info->s->base.auto_key-1].seg;
const uchar *key= (uchar*) record + keyseg->start;
switch (keyseg->type) {
case HA_KEYTYPE_INT8:
s_value= (longlong) *(const signed char*) key;
break;
case HA_KEYTYPE_BINARY:
value=(ulonglong) *(uchar*) key;
break;
case HA_KEYTYPE_SHORT_INT:
s_value= (longlong) sint2korr(key);
break;
case HA_KEYTYPE_USHORT_INT:
value=(ulonglong) uint2korr(key);
break;
case HA_KEYTYPE_LONG_INT:
s_value= (longlong) sint4korr(key);
break;
case HA_KEYTYPE_ULONG_INT:
value=(ulonglong) uint4korr(key);
break;
case HA_KEYTYPE_INT24:
s_value= (longlong) sint3korr(key);
break;
case HA_KEYTYPE_UINT24:
value=(ulonglong) uint3korr(key);
break;
case HA_KEYTYPE_FLOAT: /* This shouldn't be used */
{
float f_1;
float4get(f_1,key);
/* Ignore negative values */
value = (f_1 < (float) 0.0) ? 0 : (ulonglong) f_1;
break;
}
case HA_KEYTYPE_DOUBLE: /* This shouldn't be used */
{
double f_1;
float8get(f_1,key);
/* Ignore negative values */
value = (f_1 < 0.0) ? 0 : (ulonglong) f_1;
break;
}
case HA_KEYTYPE_LONGLONG:
s_value= sint8korr(key);
break;
case HA_KEYTYPE_ULONGLONG:
value= uint8korr(key);
break;
default:
DBUG_ASSERT(0);
value=0; /* Error */
break;
}
/*
The following code works becasue if s_value < 0 then value is 0
and if s_value == 0 then value will contain either s_value or the
correct value.
*/
return (s_value > 0) ? (ulonglong) s_value : value;
}
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