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Merge pull request #835 from tntnatbry/union-subquery

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Disable processing of a union in a subquery by the select_handler
This commit is contained in:
Andrew Hutchings
2019-09-02 06:58:06 +01:00
committed by GitHub
parent 658d50eecd e60fbf260f
commit 4d2a1594aa
1 changed files with 10 additions and 0 deletions
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10
dbcon/mysql/ha_mcs_pushdown.cpp
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@ -718,6 +718,16 @@ create_columnstore_select_handler(THD* thd, SELECT_LEX* select_lex)
return handler; return handler;
} }
// Disable SH processing for UNION in a subquery.
// This way, the server falls back to using the DH for executing
// the UNION, if enabled.
TABLE_LIST *tbl_ptr = select_lex->get_table_list();
if (tbl_ptr && tbl_ptr->derived &&
(tbl_ptr->derived->is_unit_op() || tbl_ptr->derived->fake_select_lex))
{
return handler;
}
bool unsupported_feature = false; bool unsupported_feature = false;
// Select_handler use the short-cut that effectively disables // Select_handler use the short-cut that effectively disables
// INSERT..SELECT, LDI, SELECT..INTO OUTFILE // INSERT..SELECT, LDI, SELECT..INTO OUTFILE