/*
* GetStreamPaths
*/
void
GetStreamPaths(PlannerInfo *root, RelOptInfo *baserel, Oid relid)
{
ForeignPath *path;
Cost startup_cost;
Cost total_cost;
double rows;
if (!IsContQueryProcess())
{
PlannerInfo *parent = root;
/* If the root query is continuous, we can read from streams */
while (parent->parent_root != NULL)
parent = parent->parent_root;
if (!parent->parse->isContinuous)
{
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a stream", get_rel_name(relid)),
errhint("Streams can only be read by a continuous view's FROM clause.")));
}
}
rows = Min(100, continuous_query_batch_size * 0.25);
startup_cost = baserel->baserestrictcost.startup;
total_cost = startup_cost + (cpu_tuple_cost * rows);
path = create_foreignscan_path(root, baserel, rows, startup_cost, total_cost,
NIL, NULL, NULL, NIL);
add_path(baserel, (Path *) path);
}
/*
* pglogGetForeignPaths
* Create possible access paths for a scan on the foreign table
*
* Currently we don't support any push-down feature, so there is only one
* possible access path, which simply returns all records in the order in
* the data file.
*/
static void
pglogGetForeignPaths(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid)
{
PgLogPlanState *fdw_private = (PgLogPlanState *) baserel->fdw_private;
Cost startup_cost;
Cost total_cost;
List *columns;
List *coptions = NIL;
elog(DEBUG1,"Entering function %s",__func__);
/* Decide whether to selectively perform binary conversion */
if (check_selective_binary_conversion(baserel,
foreigntableid,
&columns))
coptions = list_make1(makeDefElem("convert_selectively",
(Node *) columns));
/* Estimate costs */
estimate_costs(root, baserel, fdw_private,
&startup_cost, &total_cost);
/*
* Create a ForeignPath node and add it as only possible path. We use the
* fdw_private list of the path to carry the convert_selectively option;
* it will be propagated into the fdw_private list of the Plan node.
*/
add_path(baserel, (Path *)
create_foreignscan_path(root, baserel,
baserel->rows,
startup_cost,
total_cost,
NIL, /* no pathkeys */
NULL, /* no outer rel either */
coptions));
/*
* If data file was sorted, and we knew it somehow, we could insert
* appropriate pathkeys into the ForeignPath node to tell the planner
* that.
*/
}
static void
cassandraGetForeignPaths(PlannerInfo *root,
RelOptInfo *baserel,
Oid foreigntableid)
{
/*
* Create possible access paths for a scan on a foreign table. This is
* called during query planning. The parameters are the same as for
* GetForeignRelSize, which has already been called.
*
* This function must generate at least one access path (ForeignPath node)
* for a scan on the foreign table and must call add_path to add each such
* path to baserel->pathlist. It's recommended to use
* create_foreignscan_path to build the ForeignPath nodes. The function
* can generate multiple access paths, e.g., a path which has valid
* pathkeys to represent a pre-sorted result. Each access path must
* contain cost estimates, and can contain any FDW-private information
* that is needed to identify the specific scan method intended.
*/
/*
* CassandraFdwPlanState *fdw_private = baserel->fdw_private;
*/
Cost startup_cost,
total_cost;
elog(DEBUG1,"entering function %s",__func__);
startup_cost = 0;
total_cost = startup_cost + baserel->rows;
/* Create a ForeignPath node and add it as only possible path */
add_path(baserel, (Path *)
create_foreignscan_path(root, baserel,
baserel->rows,
startup_cost,
total_cost,
NIL, /* no pathkeys */
NULL, /* no outer rel either */
NIL)); /* no fdw_private data */
}
