database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-12 21:01:52 +03:00
Code Activity

Implement an API to let foreign-data wrappers actually be functional.

Browse Source 
This commit provides the core code and documentation needed.  A contrib
module test case will follow shortly.

Shigeru Hanada, Jan Urbanski, Heikki Linnakangas
This commit is contained in:
Tom Lane
2011-02-20 00:17:18 -05:00
parent d5813488a4
commit bb74240794
39 changed files with 1202 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
src/backend/optimizer/path/allpaths.c
View File

@ -17,6 +17,7 @@
#include <math.h>
#include "catalog/pg_class.h"
#include "nodes/nodeFuncs.h"
#ifdef OPTIMIZER_DEBUG
#include "nodes/print.h"
@ -34,6 +35,7 @@
#include "parser/parse_clause.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"
#include "utils/lsyscache.h"
/* These parameters are set by GUC */
@ -63,6 +65,8 @@ static void set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte);
static void set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte);
static void set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte);
static RelOptInfo *make_rel_from_joinlist(PlannerInfo *root, List *joinlist);
static bool subquery_is_pushdown_safe(Query *subquery, Query *topquery,
bool *differentTypes);
@ -197,9 +201,17 @@ set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
}
else
{
/* Plain relation */
Assert(rel->rtekind == RTE_RELATION);
set_plain_rel_pathlist(root, rel, rte);
if (get_rel_relkind(rte->relid) == RELKIND_FOREIGN_TABLE)
{
/* Foreign table */
set_foreign_pathlist(root, rel, rte);
}
else
{
/* Plain relation */
set_plain_rel_pathlist(root, rel, rte);
}
}
#ifdef OPTIMIZER_DEBUG
@ -904,6 +916,23 @@ set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
set_cheapest(rel);
}
/*
* set_foreign_pathlist
* Build the (single) access path for a foreign table RTE
*/
static void
set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
{
/* Mark rel with estimated output rows, width, etc */
set_foreign_size_estimates(root, rel);
/* Generate appropriate path */
add_path(rel, (Path *) create_foreignscan_path(root, rel));
/* Select cheapest path (pretty easy in this case...) */
set_cheapest(rel);
}
/*
* make_rel_from_joinlist
* Build access paths using a "joinlist" to guide the join path search.
@ -1503,6 +1532,9 @@ print_path(PlannerInfo *root, Path *path, int indent)
case T_TidPath:
ptype = "TidScan";
break;
case T_ForeignPath:
ptype = "ForeignScan";
break;
case T_AppendPath:
ptype = "Append";
break;

28
src/backend/optimizer/path/costsize.c
View File

@ -3324,6 +3324,34 @@ set_cte_size_estimates(PlannerInfo *root, RelOptInfo *rel, Plan *cteplan)
set_baserel_size_estimates(root, rel);
}
/*
* set_foreign_size_estimates
* Set the size estimates for a base relation that is a foreign table.
*
* There is not a whole lot that we can do here; the foreign-data wrapper
* is responsible for producing useful estimates. We can do a decent job
* of estimating baserestrictcost, so we set that, and we also set up width
* using what will be purely datatype-driven estimates from the targetlist.
* There is no way to do anything sane with the rows value, so we just put
* a default estimate and hope that the wrapper can improve on it. The
* wrapper's PlanForeignScan function will be called momentarily.
*
* The rel's targetlist and restrictinfo list must have been constructed
* already.
*/
void
set_foreign_size_estimates(PlannerInfo *root, RelOptInfo *rel)
{
/* Should only be applied to base relations */
Assert(rel->relid > 0);
rel->rows = 1000; /* entirely bogus default estimate */
cost_qual_eval(&rel->baserestrictcost, rel->baserestrictinfo, root);
set_rel_width(root, rel);
}
/*
* set_rel_width