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Added a comment for NULL range creation.

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ram@gw.mysql.r18.ru
2004-02-02 19:32:49 +04:00
parent 6fab168a63
commit f16dfb9d36
1 changed files with 6 additions and 1 deletions
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7
sql/opt_range.cc
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@@ -2516,6 +2516,12 @@ QUICK_SELECT *get_quick_select_for_ref(THD *thd, TABLE *table, TABLE_REF *ref)
if (quick->ranges.push_back(range)) if (quick->ranges.push_back(range))
goto err; goto err;
/*
Add a NULL range if REF_OR_NULL optimization is used.
For example:
if we have "WHERE A=2 OR A IS NULL" we created the (A=2) range above
and have ref->null_ref_key set. Will create a new NULL range here.
*/
if (ref->null_ref_key) if (ref->null_ref_key)
{ {
QUICK_RANGE *null_range; QUICK_RANGE *null_range;
@@ -2526,7 +2532,6 @@ QUICK_SELECT *get_quick_select_for_ref(THD *thd, TABLE *table, TABLE_REF *ref)
EQ_RANGE))) EQ_RANGE)))
goto err; goto err;
*ref->null_ref_key= 0; // Clear null byte *ref->null_ref_key= 0; // Clear null byte
/* Do we need to do something with key_parts here? Looks like we don't */
if (quick->ranges.push_back(null_range)) if (quick->ranges.push_back(null_range))
goto err; goto err;
} }