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Overview
Comment:Prevent the use of subroutines to implement the RHS of IN operators within CHECK constraints.
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SHA3-256: 6b24d3fb94e787d25e49501714780dfb0c0c99077102056aa68445f4808cdd57
User & Date: drh 2018-12-24 11:55:44
Context
2018-12-24
12:09
Do not generate subroutines for non-static SELECT and EXISTS expressions. Fix up some test cases to account for the minor changes in EXPLAIN QUERY PLAN output. check-in: 06de44ec user: drh tags: reuse-subqueries
11:55
Prevent the use of subroutines to implement the RHS of IN operators within CHECK constraints. check-in: 6b24d3fb user: drh tags: reuse-subqueries
02:34
Experimental code that tries to put the computation of subqueries inside a subroutine, and reuse that subroutine if the same subquery is evaluated more than once. Current code does not work for CHECK constraints. check-in: 6c44838a user: drh tags: reuse-subqueries
Changes
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Changes to src/expr.c.

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  **    *  The right-hand side is a correlated subquery
  **    *  The right-hand side is an expression list containing variables
  **    *  We are inside a trigger
  **
  ** If all of the above are false, then we can compute the RHS just once
  ** and reuse it many names.
  */
  if( !ExprHasProperty(pExpr, EP_VarSelect) ){
    /* Reuse of the RHS is allowed */
    /* If this routine has already been coded, but the previous code
    ** might not have been invoked yet, so invoke it now as a subroutine. 
    */
    if( ExprHasProperty(pExpr, EP_Subrtn) ){
      sqlite3VdbeAddOp2(v, OP_Once, 0, sqlite3VdbeCurrentAddr(v)+3);
      sqlite3VdbeAddOp2(v, OP_Gosub, pExpr->y.sub.regReturn,







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  **    *  The right-hand side is a correlated subquery
  **    *  The right-hand side is an expression list containing variables
  **    *  We are inside a trigger
  **
  ** If all of the above are false, then we can compute the RHS just once
  ** and reuse it many names.
  */
  if( !ExprHasProperty(pExpr, EP_VarSelect) && pParse->iSelfTab==0 ){
    /* Reuse of the RHS is allowed */
    /* If this routine has already been coded, but the previous code
    ** might not have been invoked yet, so invoke it now as a subroutine. 
    */
    if( ExprHasProperty(pExpr, EP_Subrtn) ){
      sqlite3VdbeAddOp2(v, OP_Once, 0, sqlite3VdbeCurrentAddr(v)+3);
      sqlite3VdbeAddOp2(v, OP_Gosub, pExpr->y.sub.regReturn,