/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB 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; either version 2 of the License, or (at your option) any later version. 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 */ /* Sorts a database */ #include "mysql_priv.h" #ifdef HAVE_STDDEF_H #include /* for macro offsetof */ #endif #include #include "sql_sort.h" #ifndef THREAD #define SKIP_DBUG_IN_FILESORT #endif /* How to write record_ref. */ #define WRITE_REF(file,from) \ if (my_b_write((file),(byte*) (from),param->ref_length)) \ DBUG_RETURN(1); /* functions defined in this file */ static char **make_char_array(register uint fields, uint length, myf my_flag); static BUFFPEK *read_buffpek_from_file(IO_CACHE *buffer_file, uint count); static ha_rows find_all_keys(SORTPARAM *param,SQL_SELECT *select, uchar * *sort_keys, 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, byte *ref_pos); static int merge_index(SORTPARAM *param,uchar *sort_buffer, BUFFPEK *buffpek, uint maxbuffer,IO_CACHE *tempfile, IO_CACHE *outfile); static bool save_index(SORTPARAM *param,uchar **sort_keys, uint count); static uint sortlength(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, byte *buff); /* Sort a table SYNOPSIS filesort() table Table to sort sortorder How to sort the table s_length Number of elements in sortorder select condition to apply to the rows special Not used. (This could be used to sort the rows pointed on by select->file) examined_rows Store number of examined rows here IMPLEMENTATION 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 REQUIREMENTS Before calling filesort, one must have done table->file->info(HA_STATUS_VARIABLE) RETURN HA_POS_ERROR Error # Number of rows examined_rows will be set to number of examined rows The result set is stored in table->io_cache or table->record_pointers */ ha_rows filesort(THD *thd, TABLE *table, SORT_FIELD *sortorder, uint s_length, SQL_SELECT *select, ha_rows max_rows, ha_rows *examined_rows) { int error; ulong memavl, min_sort_memory; uint maxbuffer; BUFFPEK *buffpek; ha_rows records= HA_POS_ERROR; uchar **sort_keys; 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 outfile= table->sort.io_cache; my_b_clear(&tempfile); my_b_clear(&buffpek_pointers); buffpek=0; sort_keys= (uchar **) NULL; error= 1; bzero((char*) ¶m,sizeof(param)); param.sort_length= sortlength(sortorder, s_length, &multi_byte_charset); param.ref_length= table->file->ref_length; param.addon_field= 0; param.addon_length= 0; if (!(table->tmp_table || table->fulltext_searched)) { /* 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, ¶m.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= (byte *) 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) { statistic_increment(filesort_range_count, &LOCK_status); } else { statistic_increment(filesort_scan_count, &LOCK_status); } #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->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=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); while (memavl >= min_sort_memory) { ulong old_memavl; ulong keys= memavl/(param.rec_length+sizeof(char*)); param.keys=(uint) min(records+1, keys); if ((sort_keys= (uchar **) make_char_array(param.keys, param.rec_length, MYF(0)))) break; old_memavl=memavl; if ((memavl=memavl/4*3) < min_sort_memory && old_memavl > min_sort_memory) memavl= min_sort_memory; } if (memavl < min_sort_memory) { my_error(ER_OUTOFMEMORY,MYF(ME_ERROR+ME_WAITTANG), thd->variables.sortbuff_size); goto err; } if (open_cached_file(&buffpek_pointers,mysql_tmpdir,TEMP_PREFIX, DISK_BUFFER_SIZE, MYF(MY_WME))) goto err; param.keys--; /* TODO: check why we do this */ param.sort_form= table; param.end=(param.local_sortorder=sortorder)+s_length; if ((records=find_all_keys(¶m,select,sort_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(¶m,sort_keys,(uint) records)) goto err; } else { if (!(buffpek=read_buffpek_from_file(&buffpek_pointers, maxbuffer))) goto err; 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(MY_WME))) goto err; reinit_io_cache(outfile,WRITE_CACHE,0L,0,0); /* 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(¶m,(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(¶m,(uchar*) sort_keys,buffpek,maxbuffer,&tempfile, outfile)) goto err; } if (records > param.max_rows) records=param.max_rows; error =0; err: if (param.tmp_buffer) x_free(param.tmp_buffer); x_free((gptr) sort_keys); x_free((gptr) buffpek); 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) my_error(ER_FILSORT_ABORT,MYF(ME_ERROR+ME_WAITTANG)); else statistic_add(filesort_rows, (ulong) records, &LOCK_status); *examined_rows= param.examined_rows; #ifdef SKIP_DBUG_IN_FILESORT DBUG_POP(); /* Ok to DBUG */ #endif DBUG_PRINT("exit",("records: %ld",records)); DBUG_RETURN(error ? HA_POS_ERROR : records); } /* filesort */ void filesort_free_buffers(TABLE *table) { if (table->sort.record_pointers) { my_free((gptr) table->sort.record_pointers,MYF(0)); table->sort.record_pointers=0; } if (table->sort.addon_buf) { my_free((char *) table->sort.addon_buf, MYF(0)); my_free((char *) table->sort.addon_field, MYF(MY_ALLOW_ZERO_PTR)); table->sort.addon_buf=0; table->sort.addon_field=0; } } /* Make a array of string pointers */ static char **make_char_array(register uint fields, uint length, myf my_flag) { register char **pos; char **old_pos,*char_pos; DBUG_ENTER("make_char_array"); if ((old_pos= (char**) my_malloc((uint) fields*(length+sizeof(char*)), my_flag))) { pos=old_pos; char_pos=((char*) (pos+fields)) -length; while (fields--) *(pos++) = (char_pos+= length); } DBUG_RETURN(old_pos); } /* make_char_array */ /* Read 'count' number of buffer pointers into memory */ static BUFFPEK *read_buffpek_from_file(IO_CACHE *buffpek_pointers, uint count) { ulong length; BUFFPEK *tmp; DBUG_ENTER("read_buffpek_from_file"); tmp=(BUFFPEK*) my_malloc(length=sizeof(BUFFPEK)*count, MYF(MY_WME)); if (tmp) { if (reinit_io_cache(buffpek_pointers,READ_CACHE,0L,0,0) || my_b_read(buffpek_pointers, (byte*) tmp, length)) { my_free((char*) tmp, MYF(0)); tmp=0; } } DBUG_RETURN(tmp); } /* Search after sort_keys and write them into tempfile. SYNOPSIS find_all_keys() param Sorting parameter select Use this to get source data sort_keys Array of pointers to sort key + addon buffers. buffpek_pointers File to write BUFFPEKs describing sorted segments in tempfile. tempfile File to write sorted sequences of sortkeys to. indexfile If !NULL, use it for source data (contains rowids) NOTE Basic idea: 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. All produced sequences are guaranteed to be non-empty. RETURN Number of records written on success. HA_POS_ERROR on error. */ static ha_rows find_all_keys(SORTPARAM *param, SQL_SELECT *select, uchar **sort_keys, IO_CACHE *buffpek_pointers, IO_CACHE *tempfile, IO_CACHE *indexfile) { int error,flag,quick_select; uint idx,indexpos,ref_length; byte *ref_pos,*next_pos,ref_buff[MAX_REFLENGTH]; my_off_t record; TABLE *sort_form; volatile my_bool *killed= ¤t_thd->killed; handler *file; 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->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) { file->reset(); // QQ; Shouldn't be needed if (sort_form->key_read) // QQ Can be removed after the reset file->extra(HA_EXTRA_KEYREAD); // QQ is removed next_pos=(byte*) 0; /* Find records in sequence */ file->ha_rnd_init(1); file->extra_opt(HA_EXTRA_CACHE, current_thd->variables.read_buff_size); } for (;;) { if (quick_select) { if ((error=select->quick->get_next())) break; file->position(sort_form->record[0]); } else /* Not quick-select */ { if (indexfile) { if (my_b_read(indexfile,(byte*) ref_pos,ref_length)) /* purecov: deadcode */ { error= my_errno ? my_errno : -1; /* Abort */ break; } error=file->rnd_pos(sort_form->record[0],next_pos); } else { error=file->rnd_next(sort_form->record[0]); if (!flag) { ha_store_ptr(ref_pos,ref_length,record); // Position to row record+=sort_form->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 */ } if (error == 0) param->examined_rows++; if (error == 0 && (!select || select->skip_record() == 0)) { if (idx == param->keys) { if (write_keys(param,sort_keys,idx,buffpek_pointers,tempfile)) DBUG_RETURN(HA_POS_ERROR); idx=0; indexpos++; } make_sortkey(param,sort_keys[idx++],ref_pos); } else file->unlock_row(); } (void) file->extra(HA_EXTRA_NO_CACHE); /* End cacheing of records */ if (!next_pos) file->ha_rnd_end(); 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 */ /* Sort the buffer and write: 1) the sorted sequence to tempfile 2) a BUFFPEK describing the sorted sequence position to buffpek_pointers (was: Skriver en buffert med nycklar till filen) SYNOPSIS write_keys() param Sort parameters sort_keys Array of pointers to keys to sort count Number of elements in sort_keys array buffpek_pointers One 'BUFFPEK' struct will be written into this file. The BUFFPEK::{file_pos, count} will indicate where the sorted data was stored. tempfile The sorted sequence will be written into this file. RETURN 0 OK 1 Error */ static int write_keys(SORTPARAM *param, register uchar **sort_keys, uint count, IO_CACHE *buffpek_pointers, IO_CACHE *tempfile) { uint 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((gptr) 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 */ 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, (byte*) *sort_keys, (uint) rec_length)) goto err; if (my_b_write(buffpek_pointers, (byte*) &buffpek, sizeof(buffpek))) goto err; DBUG_RETURN(0); err: DBUG_RETURN(1); } /* write_keys */ /* makes a sort-key from record */ static void make_sortkey(register SORTPARAM *param, register uchar *to, byte *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((char*) to,sort_field->length); } else { // Item Item *item=sort_field->item; switch (sort_field->result_type) { case STRING_RESULT: { CHARSET_INFO *cs=item->collation.collation; char fill_char= ((cs->state & MY_CS_BINSORT) ? (char) 0 : ' '); if ((maybe_null=item->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->val_str(&tmp); if (!res) { if (item->maybe_null) bzero((char*) to-1,sort_field->length+1); else { DBUG_PRINT("warning", ("Got null on something that shouldn't be null")); bzero((char*) to,sort_field->length); // Avoid crash } break; } length=res->length(); int diff=(int) (sort_field->length-length); if (diff < 0) { diff=0; /* purecov: inspected */ length=sort_field->length; } if (sort_field->need_strxnfrm) { char *from=(char*) res->ptr(); if ((unsigned char *)from == to) { set_if_smaller(length,sort_field->length); memcpy(param->tmp_buffer,from,length); from=param->tmp_buffer; } uint tmp_length=my_strnxfrm(cs,to,sort_field->length, (unsigned char *) 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: { longlong value=item->val_int(); if ((maybe_null=item->maybe_null)) *to++=1; /* purecov: inspected */ if (item->null_value) { if (item->maybe_null) bzero((char*) to-1,sort_field->length+1); else { DBUG_PRINT("warning", ("Got null on something that shouldn't be null")); bzero((char*) to,sort_field->length); } break; } #if SIZEOF_LONG_LONG > 4 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 */ #else to[3]= (uchar) value; to[2]= (uchar) (value >> 8); to[1]= (uchar) (value >> 16); if (item->unsigned_flag) /* Fix sign */ to[0]= (uchar) (value >> 24); else to[0]= (uchar) (value >> 24) ^ 128; /* Reverse signbit */ #endif break; } case REAL_RESULT: { double value=item->val(); if ((maybe_null=item->null_value)) { bzero((char*) to,sort_field->length+1); to++; break; } if ((maybe_null=item->maybe_null)) *to++=1; change_double_for_sort(value,(byte*) 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); 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_purify bzero(to, addonf->length); #endif } else { uchar *end= (uchar*) field->pack((char *) to, field->ptr); #ifdef HAVE_purify uint length= (uint) ((to + addonf->length) - end); DBUG_ASSERT((int) length >= 0); if (length) bzero(end, length); #endif } to+= addonf->length; } } else { /* Save filepos last */ memcpy((byte*) to, ref_pos, (size_s) param->ref_length); } return; } static bool save_index(SORTPARAM *param, uchar **sort_keys, uint count) { uint offset,res_length; byte *to; DBUG_ENTER("save_index"); my_string_ptr_sort((gptr) 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= param->sort_form->sort.record_pointers= (byte*) 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 int 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) { reinit_io_cache(from_file,READ_CACHE,0L,0,0); reinit_io_cache(to_file,WRITE_CACHE,0L,0,0); lastbuff=buffpek; for (i=0 ; i <= (int) *maxbuffer-MERGEBUFF*3/2 ; i+=MERGEBUFF) { if (merge_buffers(param,from_file,to_file,sort_buffer,lastbuff++, buffpek+i,buffpek+i+MERGEBUFF-1,0)) break; /* purecov: inspected */ } 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; } 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 */ /* This returns (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 (my_pread(fromfile->file,(byte*) 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 */ /* Merge buffers to one buffer SYNOPSIS merge_buffers() param Sort parameter from_file File with source data (BUFFPEKs point to this file) to_file File to write the sorted result data. sort_buffer Buffer for data to store up to MERGEBUFF2 sort keys. lastbuff OUT Store here BUFFPEK describing data written to to_file Fb First element in source BUFFPEKs array Tb Last element in source BUFFPEKs array flag RETURN 0 - OK 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,sort_length,res_length,offset; ulong maxcount; ha_rows max_rows,org_max_rows; my_off_t to_start_filepos; uchar *strpos; BUFFPEK *buffpek,**refpek; QUEUE queue; qsort2_cmp cmp; volatile my_bool *killed= ¤t_thd->killed; my_bool not_killable; DBUG_ENTER("merge_buffers"); statistic_increment(filesort_merge_passes, &LOCK_status); if (param->not_killable) { killed= ¬_killable; not_killable= 0; } error=0; rec_length= param->rec_length; res_length= param->res_length; sort_length= param->sort_length; offset= rec_length-res_length; maxcount= (ulong) (param->keys/((uint) (Tb-Fb) +1)); to_start_filepos= my_b_tell(to_file); strpos= (uchar*) 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 (init_queue(&queue, (uint) (Tb-Fb)+1, offsetof(BUFFPEK,key), 0, (queue_compare) (cmp= get_ptr_compare(sort_length)), (void*) &sort_length)) 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, (byte*) buffpek); } if (param->unique_buff) { /* Called by Unique::get() Copy the first argument to param->unique_buff for unique removal. Store it also in 'to_file'. This is safe as we know that there is always more than one element in each block to merge (This is guaranteed by the Unique:: algorithm */ buffpek= (BUFFPEK*) queue_top(&queue); memcpy(param->unique_buff, buffpek->key, rec_length); if (my_b_write(to_file, (byte*) buffpek->key, rec_length)) { error=1; goto err; /* purecov: inspected */ } buffpek->key+= rec_length; buffpek->mem_count--; if (!--max_rows) { error= 0; /* purecov: inspected */ goto end; /* purecov: inspected */ } queue_replaced(&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); if (cmp) // Remove duplicates { if (!(*cmp)(&sort_length, &(param->unique_buff), (uchar**) &buffpek->key)) goto skip_duplicate; memcpy(param->unique_buff, (uchar*) buffpek->key, rec_length); } if (flag == 0) { if (my_b_write(to_file,(byte*) buffpek->key, rec_length)) { error=1; goto err; /* purecov: inspected */ } } else { if (my_b_write(to_file, (byte*) buffpek->key+offset, res_length)) { error=1; goto err; /* purecov: inspected */ } } 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))) { uchar *base= buffpek->base; ulong max_keys= buffpek->max_keys; VOID(queue_remove(&queue,0)); /* Put room used by buffer to use in other buffer */ for (refpek= (BUFFPEK**) &queue_top(&queue); refpek <= (BUFFPEK**) &queue_end(&queue); refpek++) { buffpek= *refpek; if (buffpek->base+buffpek->max_keys*rec_length == base) { buffpek->max_keys+= max_keys; break; } else if (base+max_keys*rec_length == buffpek->base) { buffpek->base= base; buffpek->max_keys+= max_keys; break; } } break; /* One buffer have been removed */ } else if (error == -1) goto err; /* purecov: inspected */ } queue_replaced(&queue); /* Top element has been replaced */ } } buffpek= (BUFFPEK*) queue_top(&queue); buffpek->base= 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)(&sort_length, &(param->unique_buff), (uchar**) &buffpek->key)) { buffpek->key+= rec_length; // Remove duplicate --buffpek->mem_count; } } 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,(byte*) buffpek->key, (rec_length*buffpek->mem_count))) { error= 1; goto err; /* purecov: inspected */ } } else { register uchar *end; strpos= buffpek->key+offset; for (end= strpos+buffpek->mem_count*rec_length ; strpos != end ; strpos+= rec_length) { if (my_b_write(to_file, (byte *) strpos, res_length)) { 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) */ static 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 */ /* Calculate length of sort key SYNOPSIS sortlength() sortorder Order of items to sort uint s_length Number of items to sort multi_byte_charset (out) Set to 1 if we are using multi-byte charset (In which case we have to use strxnfrm()) NOTES sortorder->length is updated for each sort item sortorder->need_strxnfrm is set 1 if we have to use strxnfrm RETURN Total length of sort buffer in bytes */ static uint sortlength(SORT_FIELD *sortorder, uint s_length, bool *multi_byte_charset) { reg2 uint length; THD *thd= current_thd; CHARSET_INFO *cs; *multi_byte_charset= 0; length=0; for (; s_length-- ; sortorder++) { sortorder->need_strxnfrm= 0; if (sortorder->field) { if (sortorder->field->type() == FIELD_TYPE_BLOB) sortorder->length= thd->variables.max_sort_length; else { sortorder->length=sortorder->field->pack_length(); if (use_strnxfrm((cs=sortorder->field->sort_charset()))) { sortorder->need_strxnfrm= 1; *multi_byte_charset= 1; sortorder->length= sortorder->length*cs->strxfrm_multiply; } } if (sortorder->field->maybe_null()) length++; // Place for NULL marker } else { switch ((sortorder->result_type=sortorder->item->result_type())) { case STRING_RESULT: sortorder->length=sortorder->item->max_length; if (use_strnxfrm((cs=sortorder->item->collation.collation))) { sortorder->length= sortorder->length*cs->strxfrm_multiply; sortorder->need_strxnfrm= 1; *multi_byte_charset= 1; } break; case INT_RESULT: #if SIZEOF_LONG_LONG > 4 sortorder->length=8; // Size of intern longlong #else sortorder->length=4; #endif 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 SYNOPSIS get_addon_fields() thd Current thread ptabfields Array of references to the table fields sortlength Total length of sorted fields plength out: Total length of appended fields DESCRIPTION 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. NOTES 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 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; /* 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. */ *plength= 0; /* The following statement is added to avoid sorting in alter_table. The fact is the filter 'field->query_id != thd->query_id' doesn't work for alter table */ if (thd->lex->sql_command != SQLCOM_SELECT) return 0; for (pfield= ptabfield; (field= *pfield) ; pfield++) { if (field->query_id != thd->query_id) 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 (field->query_id != thd->query_id) 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. SYNOPSIS unpack_addon_fields() addon_field Array of descriptors for appended fields buff Buffer which to unpack the value from NOTES 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, byte *buff) { 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, (char *) buff+addonf->offset); } } /* ** 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,byte *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_fixed(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; } } }