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BUG#920255: Wrong result (extra rows) with loosescan and IN subquery

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The problem was that LooseScan execution code assumed that tab->key holds 
the index used for looseScan. This is only true when range or full index
scan are used. In case of ref access, the index is in tab->ref.key (and 
tab->index==0 which explains how LooseScan passed tests with ref access: they 
used one index)

Fixed by setting/using loosescan_key, which always the correct index#.
This commit is contained in:
Sergey Petrunya
2012-01-25 18:33:57 +04:00
parent e10816118a
commit 73cc529b51
6 changed files with 96 additions and 2 deletions
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sql/opt_subselect.cc
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@@ -4107,6 +4107,7 @@ int setup_semijoin_dups_elimination(JOIN *join, ulonglong options,
for (uint kp=0; kp < pos->loosescan_picker.loosescan_parts; kp++)
keylen += tab->table->key_info[keyno].key_part[kp].store_length;
tab->loosescan_key= keyno;
tab->loosescan_key_len= keylen;
if (pos->n_sj_tables > 1)
tab[pos->n_sj_tables - 1].do_firstmatch= tab;