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96e092dc73
WL#2474 "Multi Range Read: Change the default MRR implementation to implement new MRR interface"
WL#2475 "Batched range read functions for MyISAM/InnoDb"
"Index condition pushdown for MyISAM/InnoDB"
Igor's fix from sp1r-igor@olga.mysql.com-20080330055902-07614:
There could be observed the following problems:
1. EXPLAIN did not mention pushdown conditions from on expressions in the
'extra' column. As a result if a query had no where conditions pushed
down to a table, but had on conditions pushed to this table the 'extra'
column in the EXPLAIN for the table missed 'using where'.
2. Conditions for ref access were not eliminated from on expressions
though such conditions were eliminated from the where condition.
151 lines
5.2 KiB
C
151 lines
5.2 KiB
C
/* Copyright (C) 2002-2006 MySQL AB
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; version 2
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of the License.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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MA 02111-1307, USA */
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#ifndef _my_handler_h
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#define _my_handler_h
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#include "myisampack.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*
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There is a hard limit for the maximum number of keys as there are only
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8 bits in the index file header for the number of keys in a table.
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This means that 0..255 keys can exist for a table. The idea of
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HA_MAX_POSSIBLE_KEY is to ensure that one can use myisamchk & tools on
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a MyISAM table for which one has more keys than MyISAM is normally
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compiled for. If you don't have this, you will get a core dump when
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running myisamchk compiled for 128 keys on a table with 255 keys.
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*/
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#define HA_MAX_POSSIBLE_KEY 255 /* For myisamchk */
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/*
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The following defines can be increased if necessary.
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But beware the dependency of HA_MAX_POSSIBLE_KEY_BUFF and HA_MAX_KEY_LENGTH.
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*/
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#define HA_MAX_KEY_LENGTH 1000 /* Max length in bytes */
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#define HA_MAX_KEY_SEG 32 /* Max segments for key */
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#define HA_MAX_POSSIBLE_KEY_BUFF (HA_MAX_KEY_LENGTH + 24+ 6+6)
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#define HA_MAX_KEY_BUFF (HA_MAX_KEY_LENGTH+HA_MAX_KEY_SEG*6+8+8)
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#define HA_MAX_MSG_BUF 1024 /* used in CHECK TABLE, REPAIR TABLE */
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typedef struct st_HA_KEYSEG /* Key-portion */
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{
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CHARSET_INFO *charset;
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uint32 start; /* Start of key in record */
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uint32 null_pos; /* position to NULL indicator */
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uint16 bit_pos; /* Position to bit part */
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uint16 flag;
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uint16 length; /* Keylength */
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uint8 type; /* Type of key (for sort) */
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uint8 language;
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uint8 null_bit; /* bitmask to test for NULL */
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uint8 bit_start,bit_end; /* if bit field */
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uint8 bit_length; /* Length of bit part */
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} HA_KEYSEG;
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#define get_key_length(length,key) \
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{ if (*(const uchar*) (key) != 255) \
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length= (uint) *(const uchar*) ((key)++); \
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else \
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{ length= mi_uint2korr((key)+1); (key)+=3; } \
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}
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#define get_key_length_rdonly(length,key) \
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{ if (*(const uchar*) (key) != 255) \
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length= ((uint) *(const uchar*) ((key))); \
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else \
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{ length= mi_uint2korr((key)+1); } \
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}
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#define get_key_pack_length(length,length_pack,key) \
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{ if (*(const uchar*) (key) != 255) \
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{ length= (uint) *(const uchar*) ((key)++); length_pack= 1; }\
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else \
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{ length=mi_uint2korr((key)+1); (key)+= 3; length_pack= 3; } \
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}
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#define store_key_length_inc(key,length) \
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{ if ((length) < 255) \
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{ *(key)++= (length); } \
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else \
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{ *(key)=255; mi_int2store((key)+1,(length)); (key)+=3; } \
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}
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#define size_to_store_key_length(length) ((length) < 255 ? 1 : 3)
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#define get_rec_bits(bit_ptr, bit_ofs, bit_len) \
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(((((uint16) (bit_ptr)[1] << 8) | (uint16) (bit_ptr)[0]) >> (bit_ofs)) & \
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((1 << (bit_len)) - 1))
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#define set_rec_bits(bits, bit_ptr, bit_ofs, bit_len) \
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{ \
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(bit_ptr)[0]= ((bit_ptr)[0] & ~(((1 << (bit_len)) - 1) << (bit_ofs))) | \
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((bits) << (bit_ofs)); \
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if ((bit_ofs) + (bit_len) > 8) \
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(bit_ptr)[1]= ((bit_ptr)[1] & ~((1 << ((bit_len) - 8 + (bit_ofs))) - 1)) | \
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((bits) >> (8 - (bit_ofs))); \
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}
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#define clr_rec_bits(bit_ptr, bit_ofs, bit_len) \
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set_rec_bits(0, bit_ptr, bit_ofs, bit_len)
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extern int ha_compare_text(CHARSET_INFO *, const uchar *, uint,
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const uchar *, uint , my_bool, my_bool);
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extern int ha_key_cmp(register HA_KEYSEG *keyseg, register const uchar *a,
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register const uchar *b, uint key_length,
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uint32 nextflag, uint *diff_pos);
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extern HA_KEYSEG *ha_find_null(HA_KEYSEG *keyseg, const uchar *a);
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extern void my_handler_error_register(void);
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extern void my_handler_error_unregister(void);
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/*
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Inside an in-memory data record, memory pointers to pieces of the
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record (like BLOBs) are stored in their native byte order and in
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this amount of bytes.
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*/
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#define portable_sizeof_char_ptr 8
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/**
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Return values of index_cond_func_xxx functions.
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0=ICP_NO_MATCH - index tuple doesn't satisfy the pushed index condition (the
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engine should discard the tuple and go to the next one)
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1=ICP_MATCH - index tuple satisfies the pushed index condition (the engine
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should fetch and return the record)
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2=ICP_OUT_OF_RANGE - index tuple is out range that we're scanning, e.g. this
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if we're scanning "t.key BETWEEN 10 AND 20" and got a
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"t.key=21" tuple (the engine should stop scanning and return
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HA_ERR_END_OF_FILE right away).
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*/
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typedef enum icp_result {
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ICP_NO_MATCH,
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ICP_MATCH,
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ICP_OUT_OF_RANGE
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} ICP_RESULT;
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#ifdef __cplusplus
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}
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#endif
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#endif /* _my_handler_h */
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