diff options
Diffstat (limited to 'src/backend/executor/execUtils.c')
| -rw-r--r-- | src/backend/executor/execUtils.c | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c index 7f34d9471d8..909d9b198d0 100644 --- a/src/backend/executor/execUtils.c +++ b/src/backend/executor/execUtils.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.140.2.1 2006/12/26 21:37:28 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/execUtils.c,v 1.140.2.2 2007/02/02 00:07:28 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -578,12 +578,19 @@ ExecGetResultType(PlanState *planstate) * econtext, and storing the result into the tuple slot. (Caller must have * ensured that tuple slot has a descriptor matching the tlist!) Note that * the given tlist should be a list of ExprState nodes, not Expr nodes. + * + * inputDesc can be NULL, but if it is not, we check to see whether simple + * Vars in the tlist match the descriptor. It is important to provide + * inputDesc for relation-scan plan nodes, as a cross check that the relation + * hasn't been changed since the plan was made. At higher levels of a plan, + * there is no need to recheck. * ---------------- */ ProjectionInfo * ExecBuildProjectionInfo(List *targetList, ExprContext *econtext, - TupleTableSlot *slot) + TupleTableSlot *slot, + TupleDesc inputDesc) { ProjectionInfo *projInfo = makeNode(ProjectionInfo); int len; @@ -598,14 +605,17 @@ ExecBuildProjectionInfo(List *targetList, /* * Determine whether the target list consists entirely of simple Var - * references (ie, references to non-system attributes). If so, we can - * use the simpler ExecVariableList instead of ExecTargetList. + * references (ie, references to non-system attributes) that match the + * input. If so, we can use the simpler ExecVariableList instead of + * ExecTargetList. (Note: if there is a type mismatch then ExecEvalVar + * will probably throw an error at runtime, but we leave that to it.) */ isVarList = true; foreach(tl, targetList) { GenericExprState *gstate = (GenericExprState *) lfirst(tl); Var *variable = (Var *) gstate->arg->expr; + Form_pg_attribute attr; if (variable == NULL || !IsA(variable, Var) || @@ -614,6 +624,22 @@ ExecBuildProjectionInfo(List *targetList, isVarList = false; break; } + if (!inputDesc) + continue; /* can't check type, assume OK */ + if (variable->varattno > inputDesc->natts) + { + isVarList = false; + break; + } + attr = inputDesc->attrs[variable->varattno - 1]; + if (attr->attisdropped || + variable->vartype != attr->atttypid || + (variable->vartypmod != attr->atttypmod && + variable->vartypmod != -1)) + { + isVarList = false; + break; + } } projInfo->pi_isVarList = isVarList; @@ -689,15 +715,20 @@ ExecBuildProjectionInfo(List *targetList, * ExecAssignProjectionInfo * * forms the projection information from the node's targetlist + * + * Notes for inputDesc are same as for ExecBuildProjectionInfo: supply it + * for a relation-scan node, can pass NULL for upper-level nodes * ---------------- */ void -ExecAssignProjectionInfo(PlanState *planstate) +ExecAssignProjectionInfo(PlanState *planstate, + TupleDesc inputDesc) { planstate->ps_ProjInfo = ExecBuildProjectionInfo(planstate->targetlist, planstate->ps_ExprContext, - planstate->ps_ResultTupleSlot); + planstate->ps_ResultTupleSlot, + inputDesc); } |