diff options
Diffstat (limited to 'myisam/mi_dynrec.c')
| -rw-r--r-- | myisam/mi_dynrec.c | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/myisam/mi_dynrec.c b/myisam/mi_dynrec.c index 86d648a5af0..e1bfe4c3ac5 100644 --- a/myisam/mi_dynrec.c +++ b/myisam/mi_dynrec.c @@ -167,7 +167,6 @@ static int _mi_find_writepos(MI_INFO *info, if (info->s->state.dellink != HA_OFFSET_ERROR) { /* Deleted blocks exists; Get last used block */ - *filepos=info->s->state.dellink; block_info.second_read=0; info->rec_cache.seek_not_done=1; @@ -211,7 +210,11 @@ static int _mi_find_writepos(MI_INFO *info, -/* Remove a deleted block from the deleted list */ +/* + Unlink a deleted block from the deleted list. + This block will be combined with the preceding or next block to form + a big block. +*/ static bool unlink_deleted_block(MI_INFO *info, MI_BLOCK_INFO *block_info) { @@ -225,6 +228,7 @@ static bool unlink_deleted_block(MI_INFO *info, MI_BLOCK_INFO *block_info) { MI_BLOCK_INFO tmp; tmp.second_read=0; + /* Unlink block from the previous block */ if (!(_mi_get_block_info(&tmp,info->dfile,block_info->prev_filepos) & BLOCK_DELETED)) DBUG_RETURN(1); /* Something is wrong */ @@ -232,6 +236,7 @@ static bool unlink_deleted_block(MI_INFO *info, MI_BLOCK_INFO *block_info) if (my_pwrite(info->dfile,(char*) tmp.header+4,8, block_info->prev_filepos+4, MYF(MY_NABP))) DBUG_RETURN(1); + /* Unlink block from next block */ if (block_info->next_filepos != HA_OFFSET_ERROR) { if (!(_mi_get_block_info(&tmp,info->dfile,block_info->next_filepos) @@ -244,11 +249,16 @@ static bool unlink_deleted_block(MI_INFO *info, MI_BLOCK_INFO *block_info) DBUG_RETURN(1); } } + /* We now have one less deleted block */ info->state->del--; info->state->empty-= block_info->block_len; info->s->state.split--; - /* Removing block that we are using through mi_rrnd */ + /* + If this was a block that we where accessing through table scan + (mi_rrnd() or mi_scan(), then ensure that we skip over this block + when doing next mi_rrnd() or mi_scan(). + */ if (info->nextpos == block_info->filepos) info->nextpos+=block_info->block_len; DBUG_RETURN(0); @@ -325,7 +335,7 @@ static int delete_dynamic_record(MI_INFO *info, my_off_t filepos, info->state->empty+=length; filepos=block_info.next_filepos; - /* Now it's safe to unlink the block */ + /* Now it's safe to unlink the deleted block directly after this one */ if (remove_next_block && unlink_deleted_block(info,&del_block)) error=1; } while (!(b_type & BLOCK_LAST)); |