database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-29 05:21:33 +03:00
Code Activity

Fix for bug#5138 continued: added comments, removed extra debug printf calls, changed ha_heap::records_in_range to use table->rec_per_key.

Browse Source
This commit is contained in:
sergefp@mysql.com
2004-10-12 18:21:25 +04:00
parent 2c9d2cf671
commit a0ba02d740
7 changed files with 209 additions and 60 deletions
Download Patch File Download Diff File Expand all files Collapse all files

51
heap/hp_block.c
View File

@ -18,12 +18,19 @@
#include "heapdef.h"
/* Find record according to record-position */
/*
Find record according to record-position.
The record is located by factoring position number pos into (p_0, p_1, ...)
such that
pos = SUM_i(block->level_info[i].records_under_level * p_i)
{p_0, p_1, ...} serve as indexes to descend the blocks tree.
*/
byte *hp_find_block(HP_BLOCK *block, ulong pos)
{
reg1 int i;
reg3 HP_PTRS *ptr;
reg3 HP_PTRS *ptr; /* block base ptr */
for (i=block->levels-1, ptr=block->root ; i > 0 ; i--)
{
@ -34,8 +41,18 @@ byte *hp_find_block(HP_BLOCK *block, ulong pos)
}
/* get one new block-of-records. Alloc ptr to block if neaded */
/* Interrupts are stopped to allow ha_panic in interrupts */
/*
Get one new block-of-records. Alloc ptr to block if needed
SYNOPSIS
hp_get_new_block()
block HP_BLOCK tree-like block
alloc_length OUT Amount of memory allocated from the heap
Interrupts are stopped to allow ha_panic in interrupts
RETURN
0 OK
1 Out of memory
*/
int hp_get_new_block(HP_BLOCK *block, ulong *alloc_length)
{
@ -46,6 +63,18 @@ int hp_get_new_block(HP_BLOCK *block, ulong *alloc_length)
if (block->level_info[i].free_ptrs_in_block)
break;
/*
Allocate space for leaf block plus space for upper level blocks up to
first level that has a free slot to put the pointer.
In some cases we actually allocate more then we need:
Consider e.g. a situation where we have one level 1 block and one level 0
block, the level 0 block is full and this function is called. We only
need a leaf block in this case. Nevertheless, we will get here with i=1
and will also allocate sizeof(HP_PTRS) for non-leaf block and will never
use this space.
This doesn't add much overhead - with current values of sizeof(HP_PTRS)
and my_default_record_cache_size we get about 1/128 unused memory.
*/
*alloc_length=sizeof(HP_PTRS)*i+block->records_in_block* block->recbuffer;
if (!(root=(HP_PTRS*) my_malloc(*alloc_length,MYF(0))))
return 1;
@ -60,21 +89,33 @@ int hp_get_new_block(HP_BLOCK *block, ulong *alloc_length)
dont_break(); /* Dont allow SIGHUP or SIGINT */
if ((uint) i == block->levels)
{
/* Adding a new level on top of the existing ones. */
block->levels=i+1;
/*
Use first allocated HP_PTRS as a top-level block. Put the current
block tree into the first slot of a new top-level block.
*/
block->level_info[i].free_ptrs_in_block=HP_PTRS_IN_NOD-1;
((HP_PTRS**) root)[0]= block->root;
block->root=block->level_info[i].last_blocks= root++;
}
/* Occupy the free slot we've found at level i */
block->level_info[i].last_blocks->
blocks[HP_PTRS_IN_NOD - block->level_info[i].free_ptrs_in_block--]=
(byte*) root;
/* Add a block subtree with each node having one left-most child */
for (j=i-1 ; j >0 ; j--)
{
block->level_info[j].last_blocks= root++;
block->level_info[j].last_blocks->blocks[0]=(byte*) root;
block->level_info[j].free_ptrs_in_block=HP_PTRS_IN_NOD-1;
}
/*
root now points to last (block->records_in_block* block->recbuffer)
allocated bytes. Use it as a leaf block.
*/
block->level_info[0].last_blocks= root;
allow_break(); /* Allow SIGHUP & SIGINT */
}