| Revision | 2c3793d74fadd4897b94a896dd254541097c035d (tree) |
|---|---|
| Time | 2014-01-20 13:31:29 |
| Author | Takashi Suzuki <suzuki.takashi@metr...> |
| Commiter | Takashi Suzuki |
既存の流用関数の更新に伴い、流用関数を追加した。
流用関数を更新した結果、新しいstatistic関数を使用していたため。
core.c (diff) pg_hint_plan.c (diff)| @@ -6,6 +6,7 @@ | ||
| 6 | 6 | * src/backend/optimizer/path/allpaths.c |
| 7 | 7 | * set_append_rel_pathlist() |
| 8 | 8 | * generate_mergeappend_paths() |
| 9 | + * get_cheapest_parameterized_child_path() | |
| 9 | 10 | * accumulate_append_subpath() |
| 10 | 11 | * standard_join_search() |
| 11 | 12 | * |
| @@ -307,6 +308,79 @@ generate_mergeappend_paths(PlannerInfo *root, RelOptInfo *rel, | ||
| 307 | 308 | } |
| 308 | 309 | |
| 309 | 310 | /* |
| 311 | + * get_cheapest_parameterized_child_path | |
| 312 | + * Get cheapest path for this relation that has exactly the requested | |
| 313 | + * parameterization. | |
| 314 | + * | |
| 315 | + * Returns NULL if unable to create such a path. | |
| 316 | + */ | |
| 317 | +static Path * | |
| 318 | +get_cheapest_parameterized_child_path(PlannerInfo *root, RelOptInfo *rel, | |
| 319 | + Relids required_outer) | |
| 320 | +{ | |
| 321 | + Path *cheapest; | |
| 322 | + ListCell *lc; | |
| 323 | + | |
| 324 | + /* | |
| 325 | + * Look up the cheapest existing path with no more than the needed | |
| 326 | + * parameterization. If it has exactly the needed parameterization, we're | |
| 327 | + * done. | |
| 328 | + */ | |
| 329 | + cheapest = get_cheapest_path_for_pathkeys(rel->pathlist, | |
| 330 | + NIL, | |
| 331 | + required_outer, | |
| 332 | + TOTAL_COST); | |
| 333 | + Assert(cheapest != NULL); | |
| 334 | + if (bms_equal(PATH_REQ_OUTER(cheapest), required_outer)) | |
| 335 | + return cheapest; | |
| 336 | + | |
| 337 | + /* | |
| 338 | + * Otherwise, we can "reparameterize" an existing path to match the given | |
| 339 | + * parameterization, which effectively means pushing down additional | |
| 340 | + * joinquals to be checked within the path's scan. However, some existing | |
| 341 | + * paths might check the available joinquals already while others don't; | |
| 342 | + * therefore, it's not clear which existing path will be cheapest after | |
| 343 | + * reparameterization. We have to go through them all and find out. | |
| 344 | + */ | |
| 345 | + cheapest = NULL; | |
| 346 | + foreach(lc, rel->pathlist) | |
| 347 | + { | |
| 348 | + Path *path = (Path *) lfirst(lc); | |
| 349 | + | |
| 350 | + /* Can't use it if it needs more than requested parameterization */ | |
| 351 | + if (!bms_is_subset(PATH_REQ_OUTER(path), required_outer)) | |
| 352 | + continue; | |
| 353 | + | |
| 354 | + /* | |
| 355 | + * Reparameterization can only increase the path's cost, so if it's | |
| 356 | + * already more expensive than the current cheapest, forget it. | |
| 357 | + */ | |
| 358 | + if (cheapest != NULL && | |
| 359 | + compare_path_costs(cheapest, path, TOTAL_COST) <= 0) | |
| 360 | + continue; | |
| 361 | + | |
| 362 | + /* Reparameterize if needed, then recheck cost */ | |
| 363 | + if (!bms_equal(PATH_REQ_OUTER(path), required_outer)) | |
| 364 | + { | |
| 365 | + path = reparameterize_path(root, path, required_outer, 1.0); | |
| 366 | + if (path == NULL) | |
| 367 | + continue; /* failed to reparameterize this one */ | |
| 368 | + Assert(bms_equal(PATH_REQ_OUTER(path), required_outer)); | |
| 369 | + | |
| 370 | + if (cheapest != NULL && | |
| 371 | + compare_path_costs(cheapest, path, TOTAL_COST) <= 0) | |
| 372 | + continue; | |
| 373 | + } | |
| 374 | + | |
| 375 | + /* We have a new best path */ | |
| 376 | + cheapest = path; | |
| 377 | + } | |
| 378 | + | |
| 379 | + /* Return the best path, or NULL if we found no suitable candidate */ | |
| 380 | + return cheapest; | |
| 381 | +} | |
| 382 | + | |
| 383 | +/* | |
| 310 | 384 | * accumulate_append_subpath |
| 311 | 385 | * Add a subpath to the list being built for an Append or MergeAppend |
| 312 | 386 | * |
| @@ -413,6 +413,9 @@ static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, | ||
| 413 | 413 | static void generate_mergeappend_paths(PlannerInfo *root, RelOptInfo *rel, |
| 414 | 414 | List *live_childrels, |
| 415 | 415 | List *all_child_pathkeys); |
| 416 | +static Path *get_cheapest_parameterized_child_path(PlannerInfo *root, | |
| 417 | + RelOptInfo *rel, | |
| 418 | + Relids required_outer); | |
| 416 | 419 | static List *accumulate_append_subpath(List *subpaths, Path *path); |
| 417 | 420 | RelOptInfo *pg_hint_plan_make_join_rel(PlannerInfo *root, RelOptInfo *rel1, |
| 418 | 421 | RelOptInfo *rel2); |
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