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mariadb/sql/filesort.cc

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/*
Copyright (c) 2000, 2011, Oracle and/or its affiliates.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/**
@file
@brief
Sorts a database
*/
#include "sql_priv.h"
#include "filesort.h"
#include "unireg.h" // REQUIRED by other includes
#ifdef HAVE_STDDEF_H
#include <stddef.h> /* for macro offsetof */
#endif
#include <m_ctype.h>
#include "sql_sort.h"
#include "probes_mysql.h"
#include "sql_base.h" // update_virtual_fields
#include "sql_test.h" // TEST_filesort
#include "opt_range.h" // SQL_SELECT
#include "log_slow.h"
#include "debug_sync.h"
/// How to write record_ref.
#define WRITE_REF(file,from) \
if (my_b_write((file),(uchar*) (from),param->ref_length)) \
DBUG_RETURN(1);
/* functions defined in this file */
static uchar *read_buffpek_from_file(IO_CACHE *buffer_file, uint count,
uchar *buf);
static ha_rows find_all_keys(SORTPARAM *param,SQL_SELECT *select,
uchar * *sort_keys, uchar *sort_keys_buf,
IO_CACHE *buffer_file,
IO_CACHE *tempfile,IO_CACHE *indexfile);
static int write_keys(SORTPARAM *param,uchar * *sort_keys,
uint count, IO_CACHE *buffer_file, IO_CACHE *tempfile);
static void make_sortkey(SORTPARAM *param,uchar *to, uchar *ref_pos);
static void register_used_fields(SORTPARAM *param);
static bool save_index(SORTPARAM *param,uchar **sort_keys, uint count,
FILESORT_INFO *table_sort);
static uint suffix_length(ulong string_length);
static uint sortlength(THD *thd, SORT_FIELD *sortorder, uint s_length,
bool *multi_byte_charset);
static SORT_ADDON_FIELD *get_addon_fields(THD *thd, Field **ptabfield,
uint sortlength, uint *plength);
static void unpack_addon_fields(struct st_sort_addon_field *addon_field,
uchar *buff, uchar *buff_end);
/**
Sort a table.
Creates a set of pointers that can be used to read the rows
in sorted order. This should be done with the functions
in records.cc.
Before calling filesort, one must have done
table->file->info(HA_STATUS_VARIABLE)
The result set is stored in table->io_cache or
table->record_pointers.
@param thd Current thread
@param table Table to sort
@param sortorder How to sort the table
@param s_length Number of elements in sortorder
@param select condition to apply to the rows
@param max_rows Return only this many rows
@param sort_positions Set to 1 if we want to force sorting by position
(Needed by UPDATE/INSERT or ALTER TABLE)
@param examined_rows Store number of examined rows here
@todo
check why we do this (param.keys--)
@note
If we sort by position (like if sort_positions is 1) filesort() will
call table->prepare_for_position().
@retval
HA_POS_ERROR Error
@retval
\# Number of rows
@retval
examined_rows will be set to number of examined rows
*/
ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length,
SQL_SELECT *select, ha_rows max_rows,
bool sort_positions, ha_rows *examined_rows)
{
int error;
ulong memavl, min_sort_memory;
uint maxbuffer;
BUFFPEK *buffpek;
ha_rows records= HA_POS_ERROR;
uchar **sort_keys= 0;
IO_CACHE tempfile, buffpek_pointers, *selected_records_file, *outfile;
SORTPARAM param;
bool multi_byte_charset;
DBUG_ENTER("filesort");
DBUG_EXECUTE("info",TEST_filesort(sortorder,s_length););
#ifdef SKIP_DBUG_IN_FILESORT
DBUG_PUSH(""); /* No DBUG here */
#endif
FILESORT_INFO table_sort;
TABLE_LIST *tab= table->pos_in_table_list;
Item_subselect *subselect= tab ? tab->containing_subselect() : 0;
MYSQL_FILESORT_START(table->s->db.str, table->s->table_name.str);
DEBUG_SYNC(thd, "filesort_start");
/*
Release InnoDB's adaptive hash index latch (if holding) before
running a sort.
*/
ha_release_temporary_latches(thd);
/*
Don't use table->sort in filesort as it is also used by
QUICK_INDEX_MERGE_SELECT. Work with a copy and put it back at the end
when index_merge select has finished with it.
*/
memcpy(&table_sort, &table->sort, sizeof(FILESORT_INFO));
table->sort.io_cache= NULL;
outfile= table_sort.io_cache;
my_b_clear(&tempfile);
my_b_clear(&buffpek_pointers);
buffpek=0;
error= 1;
bzero((char*) &param,sizeof(param));
param.sort_length= sortlength(thd, sortorder, s_length, &multi_byte_charset);
param.ref_length= table->file->ref_length;
if (!(table->file->ha_table_flags() & HA_FAST_KEY_READ) &&
!table->fulltext_searched && !sort_positions)
{
/*
Get the descriptors of all fields whose values are appended
to sorted fields and get its total length in param.spack_length.
*/
param.addon_field= get_addon_fields(thd, table->field,
param.sort_length,
&param.addon_length);
}
table_sort.addon_buf= 0;
table_sort.addon_length= param.addon_length;
table_sort.addon_field= param.addon_field;
table_sort.unpack= unpack_addon_fields;
if (param.addon_field)
{
param.res_length= param.addon_length;
if (!(table_sort.addon_buf= (uchar *) my_malloc(param.addon_length,
MYF(MY_WME))))
goto err;
}
else
{
param.res_length= param.ref_length;
/*
The reference to the record is considered
as an additional sorted field
*/
param.sort_length+= param.ref_length;
}
param.rec_length= param.sort_length+param.addon_length;
param.max_rows= max_rows;
if (select && select->quick)
{
status_var_increment(thd->status_var.filesort_range_count);
}
else
{
status_var_increment(thd->status_var.filesort_scan_count);
}
thd->query_plan_flags|= QPLAN_FILESORT;
#ifdef CAN_TRUST_RANGE
if (select && select->quick && select->quick->records > 0L)
{
records=min((ha_rows) (select->quick->records*2+EXTRA_RECORDS*2),
table->file->stats.records)+EXTRA_RECORDS;
selected_records_file=0;
}
else
#endif
{
records= table->file->estimate_rows_upper_bound();
/*
If number of records is not known, use as much of sort buffer
as possible.
*/
if (records == HA_POS_ERROR)
records--; // we use 'records+1' below.
selected_records_file= 0;
}
if (multi_byte_charset &&
!(param.tmp_buffer= (char*) my_malloc(param.sort_length,MYF(MY_WME))))
goto err;
memavl= thd->variables.sortbuff_size;
min_sort_memory= max(MIN_SORT_MEMORY, param.sort_length*MERGEBUFF2);
if (!table_sort.sort_keys)
{
while (memavl >= min_sort_memory)
{
ulong old_memavl;
ulong keys= memavl/(param.rec_length+sizeof(char*));
table_sort.keys= (uint) min(records+1, keys);
DBUG_EXECUTE_IF("make_sort_keys_alloc_fail",
DBUG_SET("+d,simulate_out_of_memory"););
if ((table_sort.sort_keys=
(uchar**) my_malloc(table_sort.keys*(param.rec_length+sizeof(char*)),
MYF(0))))
break;
old_memavl=memavl;
if ((memavl=memavl/4*3) < min_sort_memory &&
old_memavl > min_sort_memory)
memavl= min_sort_memory;
}
}
sort_keys= table_sort.sort_keys;
param.keys= table_sort.keys - 1; /* TODO: check why we do this " - 1" */
if (memavl < min_sort_memory)
{
my_error(ER_OUT_OF_SORTMEMORY,MYF(ME_ERROR+ME_WAITTANG));
goto err;
}
if (open_cached_file(&buffpek_pointers,mysql_tmpdir,TEMP_PREFIX,
DISK_BUFFER_SIZE, MYF(ME_ERROR | MY_WME)))
goto err;
param.sort_form= table;
param.end=(param.local_sortorder=sortorder)+s_length;
if ((records=find_all_keys(&param,select,sort_keys,
(uchar *)(sort_keys+param.keys), &buffpek_pointers,
&tempfile, selected_records_file)) ==
HA_POS_ERROR)
goto err;
maxbuffer= (uint) (my_b_tell(&buffpek_pointers)/sizeof(*buffpek));
if (maxbuffer == 0) // The whole set is in memory
{
if (save_index(&param,sort_keys,(uint) records, &table_sort))
goto err;
}
else
{
thd->query_plan_flags|= QPLAN_FILESORT_DISK;
/* filesort cannot handle zero-length records during merge. */
DBUG_ASSERT(param.sort_length != 0);
if (table_sort.buffpek && table_sort.buffpek_len < maxbuffer)
{
my_free(table_sort.buffpek);
table_sort.buffpek= 0;
}
if (!(table_sort.buffpek=
(uchar *) read_buffpek_from_file(&buffpek_pointers, maxbuffer,
table_sort.buffpek)))
goto err;
buffpek= (BUFFPEK *) table_sort.buffpek;
table_sort.buffpek_len= maxbuffer;
close_cached_file(&buffpek_pointers);
/* Open cached file if it isn't open */
if (! my_b_inited(outfile) &&
open_cached_file(outfile,mysql_tmpdir,TEMP_PREFIX,READ_RECORD_BUFFER,
MYF(ME_ERROR | MY_WME)))
goto err;
if (reinit_io_cache(outfile,WRITE_CACHE,0L,0,0))
goto err;
/*
Use also the space previously used by string pointers in sort_buffer
for temporary key storage.
*/
param.keys=((param.keys*(param.rec_length+sizeof(char*))) /
param.rec_length-1);
maxbuffer--; // Offset from 0
if (merge_many_buff(&param,(uchar*) sort_keys,buffpek,&maxbuffer,
&tempfile))
goto err;
if (flush_io_cache(&tempfile) ||
reinit_io_cache(&tempfile,READ_CACHE,0L,0,0))
goto err;
if (merge_index(&param,(uchar*) sort_keys,buffpek,maxbuffer,&tempfile,
outfile))
goto err;
}
if (records > param.max_rows)
records=param.max_rows;
error =0;
err:
my_free(param.tmp_buffer);
if (!subselect || !subselect->is_uncacheable())
{
my_free(sort_keys);
table_sort.sort_keys= 0;
my_free(buffpek);
table_sort.buffpek= 0;
table_sort.buffpek_len= 0;
}
close_cached_file(&tempfile);
close_cached_file(&buffpek_pointers);
if (my_b_inited(outfile))
{
if (flush_io_cache(outfile))
error=1;
{
my_off_t save_pos=outfile->pos_in_file;
/* For following reads */
if (reinit_io_cache(outfile,READ_CACHE,0L,0,0))
error=1;
outfile->end_of_file=save_pos;
}
}
if (error)
{
int kill_errno= thd->killed_errno();
DBUG_ASSERT(thd->is_error() || kill_errno || thd->killed == ABORT_QUERY);
my_printf_error(ER_FILSORT_ABORT,
"%s: %s",
MYF(0),
ER_THD(thd, ER_FILSORT_ABORT),
kill_errno ? ER(kill_errno) :
thd->killed == ABORT_QUERY ? "" : thd->stmt_da->message());
if (global_system_variables.log_warnings > 1)
{
sql_print_warning("%s, host: %s, user: %s, thread: %lu, query: %-.4096s",
ER_THD(thd, ER_FILSORT_ABORT),
thd->security_ctx->host_or_ip,
&thd->security_ctx->priv_user[0],
(ulong) thd->thread_id,
thd->query());
}
}
else
statistic_add(thd->status_var.filesort_rows,
(ulong) records, &LOCK_status);
*examined_rows= param.examined_rows;
#ifdef SKIP_DBUG_IN_FILESORT
DBUG_POP(); /* Ok to DBUG */
#endif
memcpy(&table->sort, &table_sort, sizeof(FILESORT_INFO));
DBUG_PRINT("exit",("records: %ld", (long) records));
MYSQL_FILESORT_DONE(error, records);
DBUG_RETURN(error ? HA_POS_ERROR : records);
} /* filesort */
void filesort_free_buffers(TABLE *table, bool full)
{
my_free(table->sort.record_pointers);
table->sort.record_pointers= NULL;
if (full)
{
my_free(table->sort.sort_keys);
table->sort.sort_keys= NULL;
my_free(table->sort.buffpek);
table->sort.buffpek= NULL;
table->sort.buffpek_len= 0;
}
my_free(table->sort.addon_buf);
my_free(table->sort.addon_field);
table->sort.addon_buf= NULL;
table->sort.addon_field= NULL;
}
/** Read 'count' number of buffer pointers into memory. */
static uchar *read_buffpek_from_file(IO_CACHE *buffpek_pointers, uint count,
uchar *buf)
{
ulong length= sizeof(BUFFPEK)*count;
uchar *tmp= buf;
DBUG_ENTER("read_buffpek_from_file");
if (count > UINT_MAX/sizeof(BUFFPEK))
return 0; /* sizeof(BUFFPEK)*count will overflow */
if (!tmp)
tmp= (uchar *)my_malloc(length, MYF(MY_WME));
if (tmp)
{
if (reinit_io_cache(buffpek_pointers,READ_CACHE,0L,0,0) ||
my_b_read(buffpek_pointers, (uchar*) tmp, length))
{
my_free(tmp);
tmp=0;
}
}
DBUG_RETURN(tmp);
}
#ifndef DBUG_OFF
/*
Print a text, SQL-like record representation into dbug trace.
Note: this function is a work in progress: at the moment
- column read bitmap is ignored (can print garbage for unused columns)
- there is no quoting
*/
static void dbug_print_record(TABLE *table, bool print_rowid)
{
char buff[1024];
Field **pfield;
String tmp(buff,sizeof(buff),&my_charset_bin);
DBUG_LOCK_FILE;
fprintf(DBUG_FILE, "record (");
for (pfield= table->field; *pfield ; pfield++)
fprintf(DBUG_FILE, "%s%s", (*pfield)->field_name, (pfield[1])? ", ":"");
fprintf(DBUG_FILE, ") = ");
fprintf(DBUG_FILE, "(");
for (pfield= table->field; *pfield ; pfield++)
{
Field *field= *pfield;
if (field->is_null())
fwrite("NULL", sizeof(char), 4, DBUG_FILE);
if (field->type() == MYSQL_TYPE_BIT)
(void) field->val_int_as_str(&tmp, 1);
else
field->val_str(&tmp);
fwrite(tmp.ptr(),sizeof(char),tmp.length(),DBUG_FILE);
if (pfield[1])
fwrite(", ", sizeof(char), 2, DBUG_FILE);
}
fprintf(DBUG_FILE, ")");
if (print_rowid)
{
fprintf(DBUG_FILE, " rowid ");
for (uint i=0; i < table->file->ref_length; i++)
{
fprintf(DBUG_FILE, "%x", (uchar)table->file->ref[i]);
}
}
fprintf(DBUG_FILE, "\n");
DBUG_UNLOCK_FILE;
}
#endif
/**
Search after sort_keys and write them into tempfile.
All produced sequences are guaranteed to be non-empty.
@param param Sorting parameter
@param select Use this to get source data
@param sort_keys Array of pointers to sort key + addon buffers.
@param buffpek_pointers File to write BUFFPEKs describing sorted segments
in tempfile.
@param tempfile File to write sorted sequences of sortkeys to.
@param indexfile If !NULL, use it for source data (contains rowids)
@note
Basic idea:
@verbatim
while (get_next_sortkey())
{
if (no free space in sort_keys buffers)
{
sort sort_keys buffer;
dump sorted sequence to 'tempfile';
dump BUFFPEK describing sequence location into 'buffpek_pointers';
}
put sort key into 'sort_keys';
}
if (sort_keys has some elements && dumped at least once)
sort-dump-dump as above;
else
don't sort, leave sort_keys array to be sorted by caller.
@endverbatim
@retval
Number of records written on success.
@retval
HA_POS_ERROR on error.
*/
static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select,
uchar **sort_keys, uchar *sort_keys_buf,
IO_CACHE *buffpek_pointers,
IO_CACHE *tempfile, IO_CACHE *indexfile)
{
int error,flag,quick_select;
uint idx,indexpos,ref_length;
uchar *ref_pos,*next_pos,ref_buff[MAX_REFLENGTH];
my_off_t record;
TABLE *sort_form;
THD *thd= current_thd;
volatile killed_state *killed= &thd->killed;
handler *file;
MY_BITMAP *save_read_set, *save_write_set, *save_vcol_set;
uchar *next_sort_key= sort_keys_buf;
DBUG_ENTER("find_all_keys");
DBUG_PRINT("info",("using: %s",
(select ? select->quick ? "ranges" : "where":
"every row")));
idx=indexpos=0;
error=quick_select=0;
sort_form=param->sort_form;
file=sort_form->file;
ref_length=param->ref_length;
ref_pos= ref_buff;
quick_select=select && select->quick;
record=0;
flag= ((!indexfile && (file->ha_table_flags() & HA_REC_NOT_IN_SEQ))
|| quick_select);
if (indexfile || flag)
ref_pos= &file->ref[0];
next_pos=ref_pos;
if (! indexfile && ! quick_select)
{
next_pos=(uchar*) 0; /* Find records in sequence */
if (file->ha_rnd_init_with_error(1))
DBUG_RETURN(HA_POS_ERROR);
file->extra_opt(HA_EXTRA_CACHE,
current_thd->variables.read_buff_size);
}
/* Remember original bitmaps */
save_read_set= sort_form->read_set;
save_write_set= sort_form->write_set;
save_vcol_set= sort_form->vcol_set;
/* Set up temporary column read map for columns used by sort */
bitmap_clear_all(&sort_form->tmp_set);
/* Temporary set for register_used_fields and register_field_in_read_map */
sort_form->read_set= &sort_form->tmp_set;
register_used_fields(param);
Item *sort_cond= !select ?
0 : !select->pre_idx_push_select_cond ?
select->cond : select->pre_idx_push_select_cond;
if (sort_cond)
sort_cond->walk(&Item::register_field_in_read_map, 1, (uchar*) sort_form);
sort_form->column_bitmaps_set(&sort_form->tmp_set, &sort_form->tmp_set,
&sort_form->tmp_set);
if (quick_select)
{
if (select->quick->reset())
DBUG_RETURN(HA_POS_ERROR);
}
for (;;)
{
if (quick_select)
{
if ((error= select->quick->get_next()))
break;
if (!error && sort_form->vfield)
update_virtual_fields(thd, sort_form);
file->position(sort_form->record[0]);
DBUG_EXECUTE_IF("debug_filesort", dbug_print_record(sort_form, TRUE););
}
else /* Not quick-select */
{
if (indexfile)
{
if (my_b_read(indexfile,(uchar*) ref_pos,ref_length)) /* purecov: deadcode */
{
error= my_errno ? my_errno : -1; /* Abort */
break;
}
error=file->ha_rnd_pos(sort_form->record[0],next_pos);
}
else
{
error=file->ha_rnd_next(sort_form->record[0]);
if (!error && sort_form->vfield)
update_virtual_fields(thd, sort_form);
if (!flag)
{
my_store_ptr(ref_pos,ref_length,record); // Position to row
record+= sort_form->s->db_record_offset;
}
else if (!error)
file->position(sort_form->record[0]);
}
if (error && error != HA_ERR_RECORD_DELETED)
break;
}
if (*killed)
{
DBUG_PRINT("info",("Sort killed by user"));
if (!indexfile && !quick_select)
{
(void) file->extra(HA_EXTRA_NO_CACHE);
file->ha_rnd_end();
}
DBUG_RETURN(HA_POS_ERROR); /* purecov: inspected */
}
bool write_record= false;
if (error == 0)
{
param->examined_rows++;
if (select && select->cond)
{
/*
If the condition 'select->cond' contains a subquery, restore the
original read/write sets of the table 'sort_form' because when
SQL_SELECT::skip_record evaluates this condition. it may include a
correlated subquery predicate, such that some field in the subquery
refers to 'sort_form'.
PSergey-todo: discuss the above with Timour.
*/
MY_BITMAP *tmp_read_set= sort_form->read_set;
MY_BITMAP *tmp_write_set= sort_form->write_set;
MY_BITMAP *tmp_vcol_set= sort_form->vcol_set;
if (select->cond->with_subselect)
sort_form->column_bitmaps_set(save_read_set, save_write_set,
save_vcol_set);
write_record= (select->skip_record(thd) > 0);
if (select->cond->with_subselect)
sort_form->column_bitmaps_set(tmp_read_set,
tmp_write_set,
tmp_vcol_set);
}
else
write_record= true;
}
if (write_record)
{
if (idx == param->keys)
{
if (write_keys(param,sort_keys,idx,buffpek_pointers,tempfile))
DBUG_RETURN(HA_POS_ERROR);
idx=0;
next_sort_key= sort_keys_buf;
indexpos++;
}
sort_keys[idx++]= next_sort_key;
make_sortkey(param, next_sort_key, ref_pos);
next_sort_key+= param->rec_length;
}
else
file->unlock_row();
/* It does not make sense to read more keys in case of a fatal error */
if (thd->is_error())
break;
}
if (!quick_select)
{
(void) file->extra(HA_EXTRA_NO_CACHE); /* End cacheing of records */
if (!next_pos)
file->ha_rnd_end();
}
if (thd->is_error())
DBUG_RETURN(HA_POS_ERROR);
/* Signal we should use orignal column read and write maps */
sort_form->column_bitmaps_set(save_read_set, save_write_set, save_vcol_set);
DBUG_PRINT("test",("error: %d indexpos: %d",error,indexpos));
if (error != HA_ERR_END_OF_FILE)
{
file->print_error(error,MYF(ME_ERROR | ME_WAITTANG)); /* purecov: inspected */
DBUG_RETURN(HA_POS_ERROR); /* purecov: inspected */
}
if (indexpos && idx &&
write_keys(param,sort_keys,idx,buffpek_pointers,tempfile))
DBUG_RETURN(HA_POS_ERROR); /* purecov: inspected */
DBUG_RETURN(my_b_inited(tempfile) ?
(ha_rows) (my_b_tell(tempfile)/param->rec_length) :
idx);
} /* find_all_keys */
/**
@details
Sort the buffer and write:
-# the sorted sequence to tempfile
-# a BUFFPEK describing the sorted sequence position to buffpek_pointers
(was: Skriver en buffert med nycklar till filen)
@param param Sort parameters
@param sort_keys Array of pointers to keys to sort
@param count Number of elements in sort_keys array
@param buffpek_pointers One 'BUFFPEK' struct will be written into this file.
The BUFFPEK::{file_pos, count} will indicate where
the sorted data was stored.
@param tempfile The sorted sequence will be written into this file.
@retval
0 OK
@retval
1 Error
*/
static int
write_keys(SORTPARAM *param, register uchar **sort_keys, uint count,
IO_CACHE *buffpek_pointers, IO_CACHE *tempfile)
{
size_t sort_length, rec_length;
uchar **end;
BUFFPEK buffpek;
DBUG_ENTER("write_keys");
sort_length= param->sort_length;
rec_length= param->rec_length;
#ifdef MC68000
quicksort(sort_keys,count,sort_length);
#else
my_string_ptr_sort((uchar*) sort_keys, (uint) count, sort_length);
#endif
if (!my_b_inited(tempfile) &&
open_cached_file(tempfile, mysql_tmpdir, TEMP_PREFIX, DISK_BUFFER_SIZE,
MYF(MY_WME)))
goto err; /* purecov: inspected */
/* check we won't have more buffpeks than we can possibly keep in memory */
if (my_b_tell(buffpek_pointers) + sizeof(BUFFPEK) > (ulonglong)UINT_MAX)
goto err;
buffpek.file_pos= my_b_tell(tempfile);
if ((ha_rows) count > param->max_rows)
count=(uint) param->max_rows; /* purecov: inspected */
buffpek.count=(ha_rows) count;
for (end=sort_keys+count ; sort_keys != end ; sort_keys++)
if (my_b_write(tempfile, (uchar*) *sort_keys, (uint) rec_length))
goto err;
if (my_b_write(buffpek_pointers, (uchar*) &buffpek, sizeof(buffpek)))
goto err;
DBUG_RETURN(0);
err:
DBUG_RETURN(1);
} /* write_keys */
/**
Store length as suffix in high-byte-first order.
*/
static inline void store_length(uchar *to, uint length, uint pack_length)
{
switch (pack_length) {
case 1:
*to= (uchar) length;
break;
case 2:
mi_int2store(to, length);
break;
case 3:
mi_int3store(to, length);
break;
default:
mi_int4store(to, length);
break;
}
}
/** Make a sort-key from record. */
static void make_sortkey(register SORTPARAM *param,
register uchar *to, uchar *ref_pos)
{
reg3 Field *field;
reg1 SORT_FIELD *sort_field;
reg5 uint length;
for (sort_field=param->local_sortorder ;
sort_field != param->end ;
sort_field++)
{
bool maybe_null=0;
if ((field=sort_field->field))
{ // Field
if (field->maybe_null())
{
if (field->is_null())
{
if (sort_field->reverse)
bfill(to,sort_field->length+1,(char) 255);
else
bzero((char*) to,sort_field->length+1);
to+= sort_field->length+1;
continue;
}
else
*to++=1;
}
field->sort_string(to, sort_field->length);
}
else
{ // Item
Item *item=sort_field->item;
maybe_null= item->maybe_null;
switch (sort_field->result_type) {
case STRING_RESULT:
{
CHARSET_INFO *cs=item->collation.collation;
char fill_char= ((cs->state & MY_CS_BINSORT) ? (char) 0 : ' ');
int diff;
uint sort_field_length;
if (maybe_null)
*to++=1;
/* All item->str() to use some extra byte for end null.. */
String tmp((char*) to,sort_field->length+4,cs);
String *res= item->str_result(&tmp);
if (!res)
{
if (maybe_null)
bzero((char*) to-1,sort_field->length+1);
else
{
/* purecov: begin deadcode */
/*
This should only happen during extreme conditions if we run out
of memory or have an item marked not null when it can be null.
This code is here mainly to avoid a hard crash in this case.
*/
DBUG_ASSERT(0);
DBUG_PRINT("warning",
("Got null on something that shouldn't be null"));
bzero((char*) to,sort_field->length); // Avoid crash
/* purecov: end */
}
break;
}
length= res->length();
sort_field_length= sort_field->length - sort_field->suffix_length;
diff=(int) (sort_field_length - length);
if (diff < 0)
{
diff=0;
length= sort_field_length;
}
if (sort_field->suffix_length)
{
/* Store length last in result_string */
store_length(to + sort_field_length, length,
sort_field->suffix_length);
}
if (sort_field->need_strxnfrm)
{
char *from=(char*) res->ptr();
uint tmp_length __attribute__((unused));
if ((uchar*) from == to)
{
set_if_smaller(length,sort_field->length);
memcpy(param->tmp_buffer,from,length);
from=param->tmp_buffer;
}
tmp_length= my_strnxfrm(cs,to,sort_field->length,
(uchar*) from, length);
DBUG_ASSERT(tmp_length == sort_field->length);
}
else
{
my_strnxfrm(cs,(uchar*)to,length,(const uchar*)res->ptr(),length);
cs->cset->fill(cs, (char *)to+length,diff,fill_char);
}
break;
}
case INT_RESULT:
case TIME_RESULT:
{
longlong UNINIT_VAR(value);
if (sort_field->result_type == INT_RESULT)
value= item->val_int_result();
else
{
MYSQL_TIME buf;
if (item->get_date_result(&buf, TIME_FUZZY_DATE | TIME_INVALID_DATES))
DBUG_ASSERT(maybe_null && item->null_value);
else
value= pack_time(&buf);
}
if (maybe_null)
{
if (item->null_value)
{
bzero((char*) to++, sort_field->length+1);
break;
}
*to++=1; /* purecov: inspected */
}
to[7]= (uchar) value;
to[6]= (uchar) (value >> 8);
to[5]= (uchar) (value >> 16);
to[4]= (uchar) (value >> 24);
to[3]= (uchar) (value >> 32);
to[2]= (uchar) (value >> 40);
to[1]= (uchar) (value >> 48);
if (item->unsigned_flag) /* Fix sign */
to[0]= (uchar) (value >> 56);
else
to[0]= (uchar) (value >> 56) ^ 128; /* Reverse signbit */
break;
}
case DECIMAL_RESULT:
{
my_decimal dec_buf, *dec_val= item->val_decimal_result(&dec_buf);
if (maybe_null)
{
if (item->null_value)
{
bzero((char*) to++, sort_field->length+1);
break;
}
*to++=1;
}
my_decimal2binary(E_DEC_FATAL_ERROR, dec_val, to,
item->max_length - (item->decimals ? 1:0),
item->decimals);
break;
}
case REAL_RESULT:
{
double value= item->val_result();
if (maybe_null)
{
if (item->null_value)
{
bzero((char*) to,sort_field->length+1);
to++;
break;
}
*to++=1;
}
change_double_for_sort(value,(uchar*) to);
break;
}
case ROW_RESULT:
default:
// This case should never be choosen
DBUG_ASSERT(0);
break;
}
}
if (sort_field->reverse)
{ /* Revers key */
if (maybe_null)
to[-1]= ~to[-1];
length=sort_field->length;
while (length--)
{
*to = (uchar) (~ *to);
to++;
}
}
else
to+= sort_field->length;
}
if (param->addon_field)
{
/*
Save field values appended to sorted fields.
First null bit indicators are appended then field values follow.
In this implementation we use fixed layout for field values -
the same for all records.
*/
SORT_ADDON_FIELD *addonf= param->addon_field;
uchar *nulls= to;
DBUG_ASSERT(addonf != 0);
bzero((char *) nulls, addonf->offset);
to+= addonf->offset;
for ( ; (field= addonf->field) ; addonf++)
{
if (addonf->null_bit && field->is_null())
{
nulls[addonf->null_offset]|= addonf->null_bit;
#ifdef HAVE_valgrind
bzero(to, addonf->length);
#endif
}
else
{
#ifdef HAVE_valgrind
uchar *end= field->pack(to, field->ptr);
uint length= (uint) ((to + addonf->length) - end);
DBUG_ASSERT((int) length >= 0);
if (length)
bzero(end, length);
#else
(void) field->pack(to, field->ptr);
#endif
}
to+= addonf->length;
}
}
else
{
/* Save filepos last */
memcpy((uchar*) to, ref_pos, (size_t) param->ref_length);
}
return;
}
/*
Register fields used by sorting in the sorted table's read set
*/
static void register_used_fields(SORTPARAM *param)
{
reg1 SORT_FIELD *sort_field;
TABLE *table=param->sort_form;
MY_BITMAP *bitmap= table->read_set;
for (sort_field= param->local_sortorder ;
sort_field != param->end ;
sort_field++)
{
Field *field;
if ((field= sort_field->field))
{
if (field->table == table)
{
if (field->vcol_info)
{
Item *vcol_item= field->vcol_info->expr_item;
vcol_item->walk(&Item::register_field_in_read_map, 1, (uchar *) 0);
}
bitmap_set_bit(bitmap, field->field_index);
}
}
else
{ // Item
sort_field->item->walk(&Item::register_field_in_read_map, 1,
(uchar *) table);
}
}
if (param->addon_field)
{
SORT_ADDON_FIELD *addonf= param->addon_field;
Field *field;
for ( ; (field= addonf->field) ; addonf++)
bitmap_set_bit(bitmap, field->field_index);
}
else
{
/* Save filepos last */
table->prepare_for_position();
}
}
static bool save_index(SORTPARAM *param, uchar **sort_keys, uint count,
FILESORT_INFO *table_sort)
{
uint offset,res_length;
uchar *to;
DBUG_ENTER("save_index");
my_string_ptr_sort((uchar*) sort_keys, (uint) count, param->sort_length);
res_length= param->res_length;
offset= param->rec_length-res_length;
if ((ha_rows) count > param->max_rows)
count=(uint) param->max_rows;
if (!(to= table_sort->record_pointers=
(uchar*) my_malloc(res_length*count, MYF(MY_WME))))
DBUG_RETURN(1); /* purecov: inspected */
for (uchar **end= sort_keys+count ; sort_keys != end ; sort_keys++)
{
memcpy(to, *sort_keys+offset, res_length);
to+= res_length;
}
DBUG_RETURN(0);
}
/** Merge buffers to make < MERGEBUFF2 buffers. */
int merge_many_buff(SORTPARAM *param, uchar *sort_buffer,
BUFFPEK *buffpek, uint *maxbuffer, IO_CACHE *t_file)
{
register uint i;
IO_CACHE t_file2,*from_file,*to_file,*temp;
BUFFPEK *lastbuff;
DBUG_ENTER("merge_many_buff");
if (*maxbuffer < MERGEBUFF2)
DBUG_RETURN(0); /* purecov: inspected */
if (flush_io_cache(t_file) ||
open_cached_file(&t_file2,mysql_tmpdir,TEMP_PREFIX,DISK_BUFFER_SIZE,
MYF(MY_WME)))
DBUG_RETURN(1); /* purecov: inspected */
from_file= t_file ; to_file= &t_file2;
while (*maxbuffer >= MERGEBUFF2)
{
if (reinit_io_cache(from_file,READ_CACHE,0L,0,0))
goto cleanup;
if (reinit_io_cache(to_file,WRITE_CACHE,0L,0,0))
goto cleanup;
lastbuff=buffpek;
for (i=0 ; i <= *maxbuffer-MERGEBUFF*3/2 ; i+=MERGEBUFF)
{
if (merge_buffers(param,from_file,to_file,sort_buffer,lastbuff++,
buffpek+i,buffpek+i+MERGEBUFF-1,0))
goto cleanup;
}
if (merge_buffers(param,from_file,to_file,sort_buffer,lastbuff++,
buffpek+i,buffpek+ *maxbuffer,0))
break; /* purecov: inspected */
if (flush_io_cache(to_file))
break; /* purecov: inspected */
temp=from_file; from_file=to_file; to_file=temp;
setup_io_cache(from_file);
setup_io_cache(to_file);
*maxbuffer= (uint) (lastbuff-buffpek)-1;
}
cleanup:
close_cached_file(to_file); // This holds old result
if (to_file == t_file)
{
*t_file=t_file2; // Copy result file
setup_io_cache(t_file);
}
DBUG_RETURN(*maxbuffer >= MERGEBUFF2); /* Return 1 if interrupted */
} /* merge_many_buff */
/**
Read data to buffer.
@retval
(uint)-1 if something goes wrong
*/
uint read_to_buffer(IO_CACHE *fromfile, BUFFPEK *buffpek,
uint rec_length)
{
register uint count;
uint length;
if ((count=(uint) min((ha_rows) buffpek->max_keys,buffpek->count)))
{
if (mysql_file_pread(fromfile->file, (uchar*) buffpek->base,
(length= rec_length*count),
buffpek->file_pos, MYF_RW))
return((uint) -1); /* purecov: inspected */
buffpek->key=buffpek->base;
buffpek->file_pos+= length; /* New filepos */
buffpek->count-= count;
buffpek->mem_count= count;
}
return (count*rec_length);
} /* read_to_buffer */
/**
Put all room used by freed buffer to use in adjacent buffer.
Note, that we can't simply distribute memory evenly between all buffers,
because new areas must not overlap with old ones.
@param[in] queue list of non-empty buffers, without freed buffer
@param[in] reuse empty buffer
@param[in] key_length key length
*/
void reuse_freed_buff(QUEUE *queue, BUFFPEK *reuse, uint key_length)
{
uchar *reuse_end= reuse->base + reuse->max_keys * key_length;
for (uint i= queue_first_element(queue);
i <= queue_last_element(queue);
i++)
{
BUFFPEK *bp= (BUFFPEK *) queue_element(queue, i);
if (bp->base + bp->max_keys * key_length == reuse->base)
{
bp->max_keys+= reuse->max_keys;
return;
}
else if (bp->base == reuse_end)
{
bp->base= reuse->base;
bp->max_keys+= reuse->max_keys;
return;
}
}
DBUG_ASSERT(0);
}
/**
Merge buffers to one buffer.
@param param Sort parameter
@param from_file File with source data (BUFFPEKs point to this file)
@param to_file File to write the sorted result data.
@param sort_buffer Buffer for data to store up to MERGEBUFF2 sort keys.
@param lastbuff OUT Store here BUFFPEK describing data written to to_file
@param Fb First element in source BUFFPEKs array
@param Tb Last element in source BUFFPEKs array
@param flag
@retval
0 OK
@retval
other error
*/
int merge_buffers(SORTPARAM *param, IO_CACHE *from_file,
IO_CACHE *to_file, uchar *sort_buffer,
BUFFPEK *lastbuff, BUFFPEK *Fb, BUFFPEK *Tb,
int flag)
{
int error;
uint rec_length,res_length,offset;
size_t sort_length;
ulong maxcount;
ha_rows max_rows,org_max_rows;
my_off_t to_start_filepos;
uchar *strpos;
BUFFPEK *buffpek;
QUEUE queue;
qsort2_cmp cmp;
void *first_cmp_arg;
element_count dupl_count= 0;
uchar *src;
killed_state not_killable;
uchar *unique_buff= param->unique_buff;
volatile killed_state *killed= &current_thd->killed;
DBUG_ENTER("merge_buffers");
status_var_increment(current_thd->status_var.filesort_merge_passes);
current_thd->query_plan_fsort_passes++;
if (param->not_killable)
{
killed= &not_killable;
not_killable= NOT_KILLED;
}
error=0;
rec_length= param->rec_length;
res_length= param->res_length;
sort_length= param->sort_length;
uint dupl_count_ofs= rec_length-sizeof(element_count);
uint min_dupl_count= param->min_dupl_count;
bool check_dupl_count= flag && min_dupl_count;
offset= (rec_length-
(flag && min_dupl_count ? sizeof(dupl_count) : 0)-res_length);
uint wr_len= flag ? res_length : rec_length;
uint wr_offset= flag ? offset : 0;
maxcount= (ulong) (param->keys/((uint) (Tb-Fb) +1));
to_start_filepos= my_b_tell(to_file);
strpos= sort_buffer;
org_max_rows=max_rows= param->max_rows;
/* The following will fire if there is not enough space in sort_buffer */
DBUG_ASSERT(maxcount!=0);
if (unique_buff)
{
cmp= param->compare;
first_cmp_arg= (void *) &param->cmp_context;
}
else
{
cmp= get_ptr_compare(sort_length);
first_cmp_arg= (void*) &sort_length;
}
if (init_queue(&queue, (uint) (Tb-Fb)+1, offsetof(BUFFPEK,key), 0,
(queue_compare) cmp, first_cmp_arg, 0, 0))
DBUG_RETURN(1); /* purecov: inspected */
for (buffpek= Fb ; buffpek <= Tb ; buffpek++)
{
buffpek->base= strpos;
buffpek->max_keys= maxcount;
strpos+= (uint) (error= (int) read_to_buffer(from_file, buffpek,
rec_length));
if (error == -1)
goto err; /* purecov: inspected */
buffpek->max_keys= buffpek->mem_count; // If less data in buffers than expected
queue_insert(&queue, (uchar*) buffpek);
}
if (unique_buff)
{
/*
Called by Unique::get()
Copy the first argument to unique_buff for unique removal.
Store it also in 'to_file'.
*/
buffpek= (BUFFPEK*) queue_top(&queue);
memcpy(unique_buff, buffpek->key, rec_length);
if (min_dupl_count)
memcpy(&dupl_count, unique_buff+dupl_count_ofs,
sizeof(dupl_count));
buffpek->key+= rec_length;
if (! --buffpek->mem_count)
{
if (!(error= (int) read_to_buffer(from_file, buffpek,
rec_length)))
{
queue_remove(&queue,0);
reuse_freed_buff(&queue, buffpek, rec_length);
}
else if (error == -1)
goto err; /* purecov: inspected */
}
queue_replace_top(&queue); // Top element has been used
}
else
cmp= 0; // Not unique
while (queue.elements > 1)
{
if (*killed)
{
error= 1; goto err; /* purecov: inspected */
}
for (;;)
{
buffpek= (BUFFPEK*) queue_top(&queue);
src= buffpek->key;
if (cmp) // Remove duplicates
{
if (!(*cmp)(first_cmp_arg, &unique_buff,
(uchar**) &buffpek->key))
{
if (min_dupl_count)
{
element_count cnt;
memcpy(&cnt, (uchar *) buffpek->key+dupl_count_ofs, sizeof(cnt));
dupl_count+= cnt;
}
goto skip_duplicate;
}
if (min_dupl_count)
{
memcpy(unique_buff+dupl_count_ofs, &dupl_count,
sizeof(dupl_count));
}
src= unique_buff;
}
/*
Do not write into the output file if this is the final merge called
for a Unique object used for intersection and dupl_count is less
than min_dupl_count.
If the Unique object is used to intersect N sets of unique elements
then for any element:
dupl_count >= N <=> the element is occurred in each of these N sets.
*/
if (!check_dupl_count || dupl_count >= min_dupl_count)
{
if (my_b_write(to_file, src+wr_offset, wr_len))
{
error=1; goto err; /* purecov: inspected */
}
}
if (cmp)
{
memcpy(unique_buff, (uchar*) buffpek->key, rec_length);
if (min_dupl_count)
memcpy(&dupl_count, unique_buff+dupl_count_ofs,
sizeof(dupl_count));
}
if (!--max_rows)
{
error= 0; /* purecov: inspected */
goto end; /* purecov: inspected */
}
skip_duplicate:
buffpek->key+= rec_length;
if (! --buffpek->mem_count)
{
if (!(error= (int) read_to_buffer(from_file, buffpek,
rec_length)))
{
(void) queue_remove_top(&queue);
reuse_freed_buff(&queue, buffpek, rec_length);
break; /* One buffer have been removed */
}
else if (error == -1)
goto err; /* purecov: inspected */
}
queue_replace_top(&queue); /* Top element has been replaced */
}
}
buffpek= (BUFFPEK*) queue_top(&queue);
buffpek->base= (uchar*) sort_buffer;
buffpek->max_keys= param->keys;
/*
As we know all entries in the buffer are unique, we only have to
check if the first one is the same as the last one we wrote
*/
if (cmp)
{
if (!(*cmp)(first_cmp_arg, &unique_buff, (uchar**) &buffpek->key))
{
if (min_dupl_count)
{
element_count cnt;
memcpy(&cnt, (uchar *) buffpek->key+dupl_count_ofs, sizeof(cnt));
dupl_count+= cnt;
}
buffpek->key+= rec_length;
--buffpek->mem_count;
}
if (min_dupl_count)
memcpy(unique_buff+dupl_count_ofs, &dupl_count,
sizeof(dupl_count));
if (!check_dupl_count || dupl_count >= min_dupl_count)
{
src= unique_buff;
if (my_b_write(to_file, src+wr_offset, wr_len))
{
error=1; goto err; /* purecov: inspected */
}
if (!--max_rows)
{
error= 0;
goto end;
}
}
}
do
{
if ((ha_rows) buffpek->mem_count > max_rows)
{ /* Don't write too many records */
buffpek->mem_count= (uint) max_rows;
buffpek->count= 0; /* Don't read more */
}
max_rows-= buffpek->mem_count;
if (flag == 0)
{
if (my_b_write(to_file, (uchar*) buffpek->key,
(rec_length*buffpek->mem_count)))
{
error= 1; goto err; /* purecov: inspected */
}
}
else
{
register uchar *end;
src= buffpek->key+offset;
for (end= src+buffpek->mem_count*rec_length ;
src != end ;
src+= rec_length)
{
if (check_dupl_count)
{
memcpy((uchar *) &dupl_count, src+dupl_count_ofs, sizeof(dupl_count));
if (dupl_count < min_dupl_count)
continue;
}
if (my_b_write(to_file, src, wr_len))
{
error=1; goto err;
}
}
}
}
while ((error=(int) read_to_buffer(from_file, buffpek, rec_length))
!= -1 && error != 0);
end:
lastbuff->count= min(org_max_rows-max_rows, param->max_rows);
lastbuff->file_pos= to_start_filepos;
err:
delete_queue(&queue);
DBUG_RETURN(error);
} /* merge_buffers */
/* Do a merge to output-file (save only positions) */
int merge_index(SORTPARAM *param, uchar *sort_buffer,
BUFFPEK *buffpek, uint maxbuffer,
IO_CACHE *tempfile, IO_CACHE *outfile)
{
DBUG_ENTER("merge_index");
if (merge_buffers(param,tempfile,outfile,sort_buffer,buffpek,buffpek,
buffpek+maxbuffer,1))
DBUG_RETURN(1); /* purecov: inspected */
DBUG_RETURN(0);
} /* merge_index */
static uint suffix_length(ulong string_length)
{
if (string_length < 256)
return 1;
if (string_length < 256L*256L)
return 2;
if (string_length < 256L*256L*256L)
return 3;
return 4; // Can't sort longer than 4G
}
/**
Calculate length of sort key.
@param thd Thread handler
@param sortorder Order of items to sort
@param s_length Number of items to sort
@param[out] multi_byte_charset Set to 1 if we are using multi-byte charset
(In which case we have to use strxnfrm())
@note
sortorder->length is updated for each sort item.
@n
sortorder->need_strxnfrm is set 1 if we have to use strxnfrm
@return
Total length of sort buffer in bytes
*/
static uint
sortlength(THD *thd, SORT_FIELD *sortorder, uint s_length,
bool *multi_byte_charset)
{
reg2 uint length;
CHARSET_INFO *cs;
*multi_byte_charset= 0;
length=0;
for (; s_length-- ; sortorder++)
{
sortorder->need_strxnfrm= 0;
sortorder->suffix_length= 0;
if (sortorder->field)
{
cs= sortorder->field->sort_charset();
sortorder->length= sortorder->field->sort_length();
if (use_strnxfrm((cs=sortorder->field->sort_charset())))
{
sortorder->need_strxnfrm= 1;
*multi_byte_charset= 1;
sortorder->length= cs->coll->strnxfrmlen(cs, sortorder->length);
}
if (sortorder->field->maybe_null())
length++; // Place for NULL marker
}
else
{
sortorder->result_type= sortorder->item->cmp_type();
switch (sortorder->result_type) {
case STRING_RESULT:
sortorder->length=sortorder->item->max_length;
set_if_smaller(sortorder->length, thd->variables.max_sort_length);
if (use_strnxfrm((cs=sortorder->item->collation.collation)))
{
sortorder->length= cs->coll->strnxfrmlen(cs, sortorder->length);
sortorder->need_strxnfrm= 1;
*multi_byte_charset= 1;
}
else if (cs == &my_charset_bin)
{
/* Store length last to be able to sort blob/varbinary */
sortorder->suffix_length= suffix_length(sortorder->length);
sortorder->length+= sortorder->suffix_length;
}
break;
case TIME_RESULT:
case INT_RESULT:
sortorder->length=8; // Size of intern longlong
break;
case DECIMAL_RESULT:
sortorder->length=
my_decimal_get_binary_size(sortorder->item->max_length -
(sortorder->item->decimals ? 1 : 0),
sortorder->item->decimals);
break;
case REAL_RESULT:
sortorder->length=sizeof(double);
break;
case ROW_RESULT:
default:
// This case should never be choosen
DBUG_ASSERT(0);
break;
}
if (sortorder->item->maybe_null)
length++; // Place for NULL marker
}
set_if_smaller(sortorder->length, thd->variables.max_sort_length);
length+=sortorder->length;
}
sortorder->field= (Field*) 0; // end marker
DBUG_PRINT("info",("sort_length: %d",length));
return length;
}
/**
Get descriptors of fields appended to sorted fields and
calculate its total length.
The function first finds out what fields are used in the result set.
Then it calculates the length of the buffer to store the values of
these fields together with the value of sort values.
If the calculated length is not greater than max_length_for_sort_data
the function allocates memory for an array of descriptors containing
layouts for the values of the non-sorted fields in the buffer and
fills them.
@param thd Current thread
@param ptabfield Array of references to the table fields
@param sortlength Total length of sorted fields
@param[out] plength Total length of appended fields
@note
The null bits for the appended values are supposed to be put together
and stored the buffer just ahead of the value of the first field.
@return
Pointer to the layout descriptors for the appended fields, if any
@retval
NULL if we do not store field values with sort data.
*/
static SORT_ADDON_FIELD *
get_addon_fields(THD *thd, Field **ptabfield, uint sortlength, uint *plength)
{
Field **pfield;
Field *field;
SORT_ADDON_FIELD *addonf;
uint length= 0;
uint fields= 0;
uint null_fields= 0;
MY_BITMAP *read_set= (*ptabfield)->table->read_set;
/*
If there is a reference to a field in the query add it
to the the set of appended fields.
Note for future refinement:
This this a too strong condition.
Actually we need only the fields referred in the
result set. And for some of them it makes sense to use
the values directly from sorted fields.
But beware the case when item->cmp_type() != item->result_type()
*/
*plength= 0;
for (pfield= ptabfield; (field= *pfield) ; pfield++)
{
if (!bitmap_is_set(read_set, field->field_index))
continue;
if (field->flags & BLOB_FLAG)
return 0;
length+= field->max_packed_col_length(field->pack_length());
if (field->maybe_null())
null_fields++;
fields++;
}
if (!fields)
return 0;
length+= (null_fields+7)/8;
if (length+sortlength > thd->variables.max_length_for_sort_data ||
!(addonf= (SORT_ADDON_FIELD *) my_malloc(sizeof(SORT_ADDON_FIELD)*
(fields+1), MYF(MY_WME))))
return 0;
*plength= length;
length= (null_fields+7)/8;
null_fields= 0;
for (pfield= ptabfield; (field= *pfield) ; pfield++)
{
if (!bitmap_is_set(read_set, field->field_index))
continue;
addonf->field= field;
addonf->offset= length;
if (field->maybe_null())
{
addonf->null_offset= null_fields/8;
addonf->null_bit= 1<<(null_fields & 7);
null_fields++;
}
else
{
addonf->null_offset= 0;
addonf->null_bit= 0;
}
addonf->length= field->max_packed_col_length(field->pack_length());
length+= addonf->length;
addonf++;
}
addonf->field= 0; // Put end marker
DBUG_PRINT("info",("addon_length: %d",length));
return (addonf-fields);
}
/**
Copy (unpack) values appended to sorted fields from a buffer back to
their regular positions specified by the Field::ptr pointers.
@param addon_field Array of descriptors for appended fields
@param buff Buffer which to unpack the value from
@note
The function is supposed to be used only as a callback function
when getting field values for the sorted result set.
@return
void.
*/
static void
unpack_addon_fields(struct st_sort_addon_field *addon_field, uchar *buff,
uchar *buff_end)
{
Field *field;
SORT_ADDON_FIELD *addonf= addon_field;
for ( ; (field= addonf->field) ; addonf++)
{
if (addonf->null_bit && (addonf->null_bit & buff[addonf->null_offset]))
{
field->set_null();
continue;
}
field->set_notnull();
field->unpack(field->ptr, buff + addonf->offset, buff_end, 0);
}
}
/*
** functions to change a double or float to a sortable string
** The following should work for IEEE
*/
#define DBL_EXP_DIG (sizeof(double)*8-DBL_MANT_DIG)
void change_double_for_sort(double nr,uchar *to)
{
uchar *tmp=(uchar*) to;
if (nr == 0.0)
{ /* Change to zero string */
tmp[0]=(uchar) 128;
bzero((char*) tmp+1,sizeof(nr)-1);
}
else
{
#ifdef WORDS_BIGENDIAN
memcpy(tmp, &nr, sizeof(nr));
#else
{
uchar *ptr= (uchar*) &nr;
#if defined(__FLOAT_WORD_ORDER) && (__FLOAT_WORD_ORDER == __BIG_ENDIAN)
tmp[0]= ptr[3]; tmp[1]=ptr[2]; tmp[2]= ptr[1]; tmp[3]=ptr[0];
tmp[4]= ptr[7]; tmp[5]=ptr[6]; tmp[6]= ptr[5]; tmp[7]=ptr[4];
#else
tmp[0]= ptr[7]; tmp[1]=ptr[6]; tmp[2]= ptr[5]; tmp[3]=ptr[4];
tmp[4]= ptr[3]; tmp[5]=ptr[2]; tmp[6]= ptr[1]; tmp[7]=ptr[0];
#endif
}
#endif
if (tmp[0] & 128) /* Negative */
{ /* make complement */
uint i;
for (i=0 ; i < sizeof(nr); i++)
tmp[i]=tmp[i] ^ (uchar) 255;
}
else
{ /* Set high and move exponent one up */
ushort exp_part=(((ushort) tmp[0] << 8) | (ushort) tmp[1] |
(ushort) 32768);
exp_part+= (ushort) 1 << (16-1-DBL_EXP_DIG);
tmp[0]= (uchar) (exp_part >> 8);
tmp[1]= (uchar) exp_part;
}
}
}