Details
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Task
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
Description
There is a code in sql/opt_subselect.cc:
switch (outer->cmp_type()) { |
case STRING_RESULT: |
if (!(outer->collation.collation == inner->collation.collation)) |
DBUG_RETURN(FALSE);
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// Materialization does not work with BLOB columns |
if (inner->field_type() == MYSQL_TYPE_BLOB || |
inner->field_type() == MYSQL_TYPE_GEOMETRY)
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DBUG_RETURN(FALSE);
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/* |
Materialization also is unable to work when create_tmp_table() will
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create a blob column because item->max_length is too big.
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The following check is copied from Item::make_string_field():
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*/
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if (inner->too_big_for_varchar()) |
{
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DBUG_RETURN(FALSE);
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}
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break; |
case TIME_RESULT: |
if (mysql_type_to_time_type(outer->field_type()) != |
mysql_type_to_time_type(inner->field_type()))
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DBUG_RETURN(FALSE);
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default: |
/* suitable for materialization */ |
break; |
}
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It's not friendly for new data types. It uses a switch on cmp_type() and uses mysql_type_to_time_type(outer->field_type()).
Under terms of this task we'll
1. Introduce two new virtual methods in Type_handler:
virtual enum_mysql_timestamp_type mysql_timestamp_type() const;
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virtual bool subquery_type_allows_materialization(const Item *inner, const Item *outer) const;
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2. Split the above code into virtual implementations for corresponding type handlers.
3. Replace calls mysql_type_to_time_type(field_type()) to type_handler()->mysql_timestamp_type()
Attachments
Issue Links
- blocks
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MDEV-4912 Data type plugin API version 1
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- Closed
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