针对存储过程的Oracle性能调优

Question

A scenario encountered recently where I have lots of select statements as:

and  (UPPER(Table1.col1) LIKE UPPER(v_param1)||'%' or v_param1 is NULL)
and  (UPPER(Table2.col2) LIKE UPPER(v_param2)||'%' or v_param2 is NULL)

v_param1 & v_param2 are inputs to the stored procedure, I need to optimize the query. Is there any way to check if the v_param1,v_param1 are NULL then no need to check for the first condition before Or.

Answer 1

Remove that or and change the condition like below

and upper(Table1.col1) like upper(v_param1)||'%' and upper(Table2.col2) like upper(v_param2)||'%'

Note: if param value is null then it will execute the condition like "upper(col1) like '%'"

Answer 2

The simplest thing you could do is to switch the order in which the conditions are evaluated:

and  (v_param1 is NULL or UPPER(Table1.col1) LIKE UPPER(v_param1)||'%'  )
and  (v_param2 is NULL or UPPER(Table2.col2) LIKE UPPER(v_param2)||'%'  )

Oracle does not guarantee to short-circuit the OR evaluation, but leading with the NULL test gives it a nudge in the right direction.

Answer 3

If you use stored procedure then you can construct your query dynamically in pl/sql, bind variables and execute query using dbms_sql.

...
  sSQL varchar2(32767) := 'select col1, col2 from Table1';
  iCurrId            number := DBMS_SQL.OPEN_CURSOR;
  iCurRes            number;
begin
  -- constant conditions
  sSQL := sSQL||' where col3 = :column3_value';

  -- add condition for v_param1 if it is not null  
  if v_param1 is not null then
    sSQL := sSQL||' and UPPER(Table1.col1) LIKE :v_param1_search_value';
  end if;

  -- add condition for v_param2 if it is not null  
  if v_param2 is not null then
    sSQL := sSQL||' and UPPER(Table1.col2) LIKE :v_param2_search_value';
  end if;

  -- parse cursor
  DBMS_SQL.PARSE(
    C             => iCurrId,
    STATEMENT     => sSQL,
    LANGUAGE_FLAG => DBMS_SQL.NATIVE
  );

  -- bind variables
  DBMS_SQL.BIND_VARIABLE( C => iCurrId, NAME => 'column3_value', VALUE => 'abcd');

  if v_param1 is not null then
    DBMS_SQL.BIND_VARIABLE( C => iCurrId, NAME => 'v_param1_search_value', VALUE => UPPER(v_param1)||'%');
  end if;

  if v_param2 is not null then
    DBMS_SQL.BIND_VARIABLE( C => iCurrId, NAME => 'v_param2_search_value', VALUE => UPPER(v_param2)||'%');
  end if;

  -- execute query
  iCurRes := DBMS_SQL.EXECUTE(iCurrId);
...

Answer 4

try to use:

AND (
  CASE
    WHEN v_param2 IS NULL
    THEN NULL
    ELSE UPPER(Table2.col2)
  END LIKE UPPER(v_param2)
  ||'%'
OR v_param2      IS NULL)