greenplumn pxf_deparse 源码
greenplumn pxf_deparse 代码
文件路径：/gpcontrib/pxf_fdw/pxf_deparse.c
/*-------------------------------------------------------------------------
*
* pxf_deparse.c
* Query deparser for pxf_fdw
*
* This file includes functions that examine query WHERE clauses to see
* whether they're safe to send to the remote server for execution.
*
* IDENTIFICATION
* contrib/pxf_fdw/pxf_deparse.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "pxf_fdw.h"
/*
* We create an integer List of the columns being retrieved, which is
* returned to *retrieved_attrs.
*/
void
deparseTargetList(Relation rel, Bitmapset *attrs_used, List **retrieved_attrs)
{
TupleDesc tupdesc = RelationGetDescr(rel);
bool have_wholerow;
int i;
*retrieved_attrs = NIL;
/* If there's a whole-row reference, we'll need all the columns. */
have_wholerow = bms_is_member(0 - FirstLowInvalidHeapAttributeNumber, attrs_used);
if (have_wholerow)
return;
for (i = 1; i <= tupdesc->natts; i++)
{
Form_pg_attribute attr = TupleDescAttr(tupdesc, i - 1);
/* Ignore dropped attributes. */
if (attr->attisdropped)
continue;
if (bms_is_member(i - FirstLowInvalidHeapAttributeNumber, attrs_used))
{
*retrieved_attrs = lappend_int(*retrieved_attrs, i);
}
}
}
/*
* Examine each qual clause in input_conds, and classify them into two groups,
* which are returned as two lists:
* - remote_conds contains expressions that can be evaluated remotely
* - local_conds contains expressions that can't be evaluated remotely
*/
void
classifyConditions(PlannerInfo *root,
RelOptInfo *baserel,
List *input_conds,
List **remote_conds,
List **local_conds)
{
ListCell *lc;
*remote_conds = NIL;
*local_conds = NIL;
foreach(lc, input_conds)
{
RestrictInfo *ri = (RestrictInfo *) lfirst(lc);
/* for now, just assume that all WHERE clauses are OK on remote */
*remote_conds = lappend(*remote_conds, ri);
}
}
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