/* ----------------
* ExecBuildProjectionInfo
*
* Build a ProjectionInfo node for evaluating the given tlist in the given
* 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,
TupleDesc inputDesc)
{
ProjectionInfo *projInfo = makeNode(ProjectionInfo);
int len = ExecTargetListLength(targetList);
int *workspace;
int *varSlotOffsets;
int *varNumbers;
int *varOutputCols;
List *exprlist;
int numSimpleVars;
bool directMap;
ListCell *tl;
projInfo->pi_exprContext = econtext;
projInfo->pi_slot = slot;
/* since these are all int arrays, we need do just one palloc */
workspace = (int *) palloc(len * 3 * sizeof(int));
projInfo->pi_varSlotOffsets = varSlotOffsets = workspace;
projInfo->pi_varNumbers = varNumbers = workspace + len;
projInfo->pi_varOutputCols = varOutputCols = workspace + len * 2;
projInfo->pi_lastInnerVar = 0;
projInfo->pi_lastOuterVar = 0;
projInfo->pi_lastScanVar = 0;
/*
* We separate the target list elements into simple Var references and
* expressions which require the full ExecTargetList machinery. To be a
* simple Var, a Var has to be a user attribute and not mismatch the
* inputDesc. (Note: if there is a type mismatch then ExecEvalScalarVar
* will probably throw an error at runtime, but we leave that to it.)
*/
exprlist = NIL;
numSimpleVars = 0;
directMap = true;
foreach(tl, targetList)
{
GenericExprState *gstate = (GenericExprState *) lfirst(tl);
Var *variable = (Var *) gstate->arg->expr;
bool isSimpleVar = false;
if (variable != NULL &&
IsA(variable, Var) &&
variable->varattno > 0)
{
if (!inputDesc)
isSimpleVar = true; /* can't check type, assume OK */
else if (variable->varattno <= inputDesc->natts)
{
Form_pg_attribute attr;
attr = inputDesc->attrs[variable->varattno - 1];
if (!attr->attisdropped && variable->vartype == attr->atttypid)
isSimpleVar = true;
}
}
if (isSimpleVar)
{
TargetEntry *tle = (TargetEntry *) gstate->xprstate.expr;
AttrNumber attnum = variable->varattno;
varNumbers[numSimpleVars] = attnum;
varOutputCols[numSimpleVars] = tle->resno;
if (tle->resno != numSimpleVars + 1)
directMap = false;
switch (variable->varno)
{
case INNER_VAR:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_innertuple);
if (projInfo->pi_lastInnerVar < attnum)
projInfo->pi_lastInnerVar = attnum;
break;
case OUTER_VAR:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_outertuple);
if (projInfo->pi_lastOuterVar < attnum)
projInfo->pi_lastOuterVar = attnum;
break;
/* INDEX_VAR is handled by default case */
default:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_scantuple);
if (projInfo->pi_lastScanVar < attnum)
projInfo->pi_lastScanVar = attnum;
break;
}
numSimpleVars++;
}
else
{
/* Not a simple variable, add it to generic targetlist */
exprlist = lappend(exprlist, gstate);
/* Examine expr to include contained Vars in lastXXXVar counts */
get_last_attnums((Node *) variable, projInfo);
}
}
/* ----------------
* ExecBuildProjectionInfo
*
* Build a projection_info_n node for evaluating the given tlist in the given
* 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 expr_state_n nodes, not expr_n 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.
* ----------------
*/
projection_info_n*
ExecBuildProjectionInfo(
struct list *targetList,
expr_ctx_n *econtext,
struct tupslot *slot,
struct tuple * inputDesc)
{
projection_info_n *projInfo = MK_N(ProjectionInfo,projection_info_n);
int len = exec_tgtlist_len(targetList);
int* workspace;
int* varSlotOffsets;
int* varNumbers;
int* varOutputCols;
struct list* exprlist;
int numSimpleVars;
bool directMap;
struct list_cell *tl;
projInfo->pi_exprContext = econtext;
projInfo->pi_slot = slot;
/* since these are all int arrays, we need do just one palloc */
workspace = (int *) palloc(len * 3 * sizeof(int));
projInfo->pi_varSlotOffsets = varSlotOffsets = workspace;
projInfo->pi_varNumbers = varNumbers = workspace + len;
projInfo->pi_varOutputCols = varOutputCols = workspace + len * 2;
projInfo->pi_lastInnerVar = 0;
projInfo->pi_lastOuterVar = 0;
projInfo->pi_lastScanVar = 0;
/*
* We separate the target list elements into simple var_xp references and
* expressions which require the full ExecTargetList machinery. To be a
* simple var_xp, a var_xp has to be a user attribute and not mismatch the
* inputDesc. (Note: if there is a type mismatch then ExecEvalVar will
* probably throw an error at runtime, but we leave that to it.)
*/
exprlist = NIL;
numSimpleVars = 0;
directMap = true;
foreach(tl, targetList) {
generic_xs *gstate = (generic_xs *) lfirst(tl);
var_xp* variable = (var_xp *) gstate->arg->expr;
bool isSimpleVar = false;
if (variable != NULL
&& IS_A(variable, Var)
&& variable->varattno > 0) {
if (!inputDesc) {
isSimpleVar = true; /* can't check type, assume OK */
} else if (variable->varattno <= inputDesc->natts) {
Form_pg_attribute attr;
attr = inputDesc->attrs[variable->varattno - 1];
if (!attr->attisdropped && variable->vartype == attr->atttypid)
isSimpleVar = true;
}
}
if (isSimpleVar) {
tgt_entry_xp *tle = (tgt_entry_xp *) gstate->xprstate.expr;
attr_nr_t attnum = variable->varattno;
varNumbers[numSimpleVars] = attnum;
varOutputCols[numSimpleVars] = tle->resno;
if (tle->resno != numSimpleVars + 1)
directMap = false;
switch (variable->varno) {
case INNER:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_innertuple);
if (projInfo->pi_lastInnerVar < attnum)
projInfo->pi_lastInnerVar = attnum;
break;
case OUTER:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_outertuple);
if (projInfo->pi_lastOuterVar < attnum)
projInfo->pi_lastOuterVar = attnum;
break;
default:
varSlotOffsets[numSimpleVars] = offsetof(ExprContext,
ecxt_scantuple);
if (projInfo->pi_lastScanVar < attnum)
projInfo->pi_lastScanVar = attnum;
break;
}
numSimpleVars++;
} else {
/* Not a simple variable, add it to generic targetlist */
exprlist = lappend(exprlist, gstate);
/* Examine expr to include contained Vars in lastXXXVar counts */
get_last_attnums((node_n *) variable, projInfo);
}
}
