/*
* pglogGetForeignPlan
* Create a ForeignScan plan node for scanning the foreign table
*/
static ForeignScan *
pglogGetForeignPlan(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid,
ForeignPath *best_path,
List *tlist,
List *scan_clauses)
{
Index scan_relid = baserel->relid;
elog(DEBUG1,"Entering function %s",__func__);
/*
* We have no native ability to evaluate restriction clauses, so we just
* put all the scan_clauses into the plan node's qual list for the
* executor to check. So all we have to do here is strip RestrictInfo
* nodes from the clauses and ignore pseudoconstants (which will be
* handled elsewhere).
*/
scan_clauses = extract_actual_clauses(scan_clauses, false);
/* Create the ForeignScan node */
return make_foreignscan(tlist,
scan_clauses,
scan_relid,
NIL, /* no expressions to evaluate */
best_path->fdw_private);
}
static ForeignScan *
cassandraGetForeignPlan(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid,
ForeignPath *best_path,
List *tlist,
List *scan_clauses)
{
/*
* Create a ForeignScan plan node from the selected foreign access path.
* This is called at the end of query planning. The parameters are as for
* GetForeignRelSize, plus the selected ForeignPath (previously produced
* by GetForeignPaths), the target list to be emitted by the plan node,
* and the restriction clauses to be enforced by the plan node.
*
* This function must create and return a ForeignScan plan node; it's
* recommended to use make_foreignscan to build the ForeignScan node.
*
*/
Index scan_relid = baserel->relid;
/*
* We have no native ability to evaluate restriction clauses, so we just
* put all the scan_clauses into the plan node's qual list for the
* executor to check. So all we have to do here is strip RestrictInfo
* nodes from the clauses and ignore pseudoconstants (which will be
* handled elsewhere).
*/
elog(DEBUG1,"entering function %s",__func__);
scan_clauses = extract_actual_clauses(scan_clauses, false);
/* Create the ForeignScan node */
return make_foreignscan(tlist,
scan_clauses,
scan_relid,
NIL, /* no expressions to evaluate */
NIL); /* no private state either */
}
/*
* GetStreamScanPlan
*/
ForeignScan *
GetStreamScanPlan(PlannerInfo *root, RelOptInfo *baserel,
Oid relid, ForeignPath *best_path, List *tlist, List *scan_clauses, Plan *outer_plan)
{
StreamFdwInfo *sinfo = (StreamFdwInfo *) baserel->fdw_private;
List *physical_tlist = build_physical_tlist(root, baserel);
RangeTblEntry *rte = NULL;
int i;
TableSampleClause *sample;
Value *sample_cutoff = NULL;
/* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
scan_clauses = extract_actual_clauses(scan_clauses, false);
for (i = 1; i <= root->simple_rel_array_size; i++)
{
rte = root->simple_rte_array[i];
if (rte && rte->relid == relid)
break;
}
if (!rte || rte->relid != relid)
elog(ERROR, "stream RTE missing");
sample = rte->tablesample;
if (sample)
{
double dcutoff;
Datum d;
ExprContext *econtext;
bool isnull;
Node *node;
Expr *expr;
ExprState *estate;
ParseState *ps = make_parsestate(NULL);
float4 percent;
if (sample->tsmhandler != BERNOULLI_OID)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("tablesample method %s is not supported by streams", get_func_name(sample->tsmhandler)),
errhint("Only bernoulli tablesample method can be used with streams.")));
if (sample->repeatable)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("streams don't support the REPEATABLE clause for tablesample")));
econtext = CreateStandaloneExprContext();
ps = make_parsestate(NULL);
node = (Node *) linitial(sample->args);
node = transformExpr(ps, node, EXPR_KIND_OTHER);
expr = expression_planner((Expr *) node);
estate = ExecInitExpr(expr, NULL);
d = ExecEvalExpr(estate, econtext, &isnull, NULL);
free_parsestate(ps);
FreeExprContext(econtext, false);
percent = DatumGetFloat4(d);
if (percent < 0 || percent > 100 || isnan(percent))
ereport(ERROR,
(errcode(ERRCODE_INVALID_TABLESAMPLE_ARGUMENT),
errmsg("sample percentage must be between 0 and 100")));
dcutoff = rint(((double) RAND_MAX + 1) * percent / 100);
sample_cutoff = makeInteger((int) dcutoff);
}
return make_foreignscan(tlist, scan_clauses, baserel->relid,
NIL, list_make3(sinfo->colnames, physical_tlist, sample_cutoff), NIL, NIL, outer_plan);
}
