diff options
Diffstat (limited to 'contrib/postgres_fdw/postgres_fdw.c')
| -rw-r--r-- | contrib/postgres_fdw/postgres_fdw.c | 195 |
1 files changed, 123 insertions, 72 deletions
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c index 8d022437beb..18b4b01cfa4 100644 --- a/contrib/postgres_fdw/postgres_fdw.c +++ b/contrib/postgres_fdw/postgres_fdw.c @@ -414,6 +414,11 @@ static void add_paths_with_pathkeys_for_rel(PlannerInfo *root, RelOptInfo *rel, static void add_foreign_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel, RelOptInfo *grouped_rel); +static void apply_server_options(PgFdwRelationInfo *fpinfo); +static void apply_table_options(PgFdwRelationInfo *fpinfo); +static void merge_fdw_options(PgFdwRelationInfo *fpinfo, + const PgFdwRelationInfo *fpinfo_o, + const PgFdwRelationInfo *fpinfo_i); /* @@ -513,31 +518,8 @@ postgresGetForeignRelSize(PlannerInfo *root, fpinfo->shippable_extensions = NIL; fpinfo->fetch_size = 100; - foreach(lc, fpinfo->server->options) - { - DefElem *def = (DefElem *) lfirst(lc); - - if (strcmp(def->defname, "use_remote_estimate") == 0) - fpinfo->use_remote_estimate = defGetBoolean(def); - else if (strcmp(def->defname, "fdw_startup_cost") == 0) - fpinfo->fdw_startup_cost = strtod(defGetString(def), NULL); - else if (strcmp(def->defname, "fdw_tuple_cost") == 0) - fpinfo->fdw_tuple_cost = strtod(defGetString(def), NULL); - else if (strcmp(def->defname, "extensions") == 0) - fpinfo->shippable_extensions = - ExtractExtensionList(defGetString(def), false); - else if (strcmp(def->defname, "fetch_size") == 0) - fpinfo->fetch_size = strtol(defGetString(def), NULL, 10); - } - foreach(lc, fpinfo->table->options) - { - DefElem *def = (DefElem *) lfirst(lc); - - if (strcmp(def->defname, "use_remote_estimate") == 0) - fpinfo->use_remote_estimate = defGetBoolean(def); - else if (strcmp(def->defname, "fetch_size") == 0) - fpinfo->fetch_size = strtol(defGetString(def), NULL, 10); - } + apply_server_options(fpinfo); + apply_table_options(fpinfo); /* * If the table or the server is configured to use remote estimates, @@ -4115,6 +4097,15 @@ foreign_join_ok(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype, return false; /* + * Merge FDW options. We might be tempted to do this after we have deemed + * the foreign join to be OK. But we must do this beforehand so that we + * know which quals can be evaluated on the foreign server, which might + * depend on shippable_extensions. + */ + fpinfo->server = fpinfo_o->server; + merge_fdw_options(fpinfo, fpinfo_o, fpinfo_i); + + /* * Separate restrict list into join quals and pushed-down (other) quals. * * Join quals belonging to an outer join must all be shippable, else we @@ -4279,15 +4270,6 @@ foreign_join_ok(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype, /* Mark that this join can be pushed down safely */ fpinfo->pushdown_safe = true; - /* - * If user is willing to estimate cost for a scan of either of the joining - * relations using EXPLAIN, he intends to estimate scans on that relation - * more accurately. Then, it makes sense to estimate the cost of the join - * with that relation more accurately using EXPLAIN. - */ - fpinfo->use_remote_estimate = fpinfo_o->use_remote_estimate || - fpinfo_i->use_remote_estimate; - /* Get user mapping */ if (fpinfo->use_remote_estimate) { @@ -4299,17 +4281,6 @@ foreign_join_ok(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype, else fpinfo->user = NULL; - /* Get foreign server */ - fpinfo->server = fpinfo_o->server; - - /* - * Since both the joining relations come from the same server, the server - * level options should have same value for both the relations. Pick from - * any side. - */ - fpinfo->fdw_startup_cost = fpinfo_o->fdw_startup_cost; - fpinfo->fdw_tuple_cost = fpinfo_o->fdw_tuple_cost; - /* * Set cached relation costs to some negative value, so that we can detect * when they are set to some sensible costs, during one (usually the @@ -4319,15 +4290,6 @@ foreign_join_ok(PlannerInfo *root, RelOptInfo *joinrel, JoinType jointype, fpinfo->rel_total_cost = -1; /* - * Set fetch size to maximum of the joining sides, since we are expecting - * the rows returned by the join to be proportional to the relation sizes. - */ - if (fpinfo_o->fetch_size > fpinfo_i->fetch_size) - fpinfo->fetch_size = fpinfo_o->fetch_size; - else - fpinfo->fetch_size = fpinfo_i->fetch_size; - - /* * Set the string describing this join relation to be used in EXPLAIN * output of corresponding ForeignScan. */ @@ -4385,6 +4347,110 @@ add_paths_with_pathkeys_for_rel(PlannerInfo *root, RelOptInfo *rel, } /* + * Parse options from foreign server and apply them to fpinfo. + * + * New options might also require tweaking merge_fdw_options(). + */ +static void +apply_server_options(PgFdwRelationInfo *fpinfo) +{ + ListCell *lc; + + foreach(lc, fpinfo->server->options) + { + DefElem *def = (DefElem *) lfirst(lc); + + if (strcmp(def->defname, "use_remote_estimate") == 0) + fpinfo->use_remote_estimate = defGetBoolean(def); + else if (strcmp(def->defname, "fdw_startup_cost") == 0) + fpinfo->fdw_startup_cost = strtod(defGetString(def), NULL); + else if (strcmp(def->defname, "fdw_tuple_cost") == 0) + fpinfo->fdw_tuple_cost = strtod(defGetString(def), NULL); + else if (strcmp(def->defname, "extensions") == 0) + fpinfo->shippable_extensions = + ExtractExtensionList(defGetString(def), false); + else if (strcmp(def->defname, "fetch_size") == 0) + fpinfo->fetch_size = strtol(defGetString(def), NULL, 10); + } +} + +/* + * Parse options from foreign table and apply them to fpinfo. + * + * New options might also require tweaking merge_fdw_options(). + */ +static void +apply_table_options(PgFdwRelationInfo *fpinfo) +{ + ListCell *lc; + + foreach(lc, fpinfo->table->options) + { + DefElem *def = (DefElem *) lfirst(lc); + + if (strcmp(def->defname, "use_remote_estimate") == 0) + fpinfo->use_remote_estimate = defGetBoolean(def); + else if (strcmp(def->defname, "fetch_size") == 0) + fpinfo->fetch_size = strtol(defGetString(def), NULL, 10); + } +} + +/* + * Merge FDW options from input relations into a new set of options for a join + * or an upper rel. + * + * For a join relation, FDW-specific information about the inner and outer + * relations is provided using fpinfo_i and fpinfo_o. For an upper relation, + * fpinfo_o provides the information for the input relation; fpinfo_i is + * expected to NULL. + */ +static void +merge_fdw_options(PgFdwRelationInfo *fpinfo, + const PgFdwRelationInfo *fpinfo_o, + const PgFdwRelationInfo *fpinfo_i) +{ + /* We must always have fpinfo_o. */ + Assert(fpinfo_o); + + /* fpinfo_i may be NULL, but if present the servers must both match. */ + Assert(!fpinfo_i || + fpinfo_i->server->serverid == fpinfo_o->server->serverid); + + /* + * Copy the server specific FDW options. (For a join, both relations come + * from the same server, so the server options should have the same value + * for both relations.) + */ + fpinfo->fdw_startup_cost = fpinfo_o->fdw_startup_cost; + fpinfo->fdw_tuple_cost = fpinfo_o->fdw_tuple_cost; + fpinfo->shippable_extensions = fpinfo_o->shippable_extensions; + fpinfo->use_remote_estimate = fpinfo_o->use_remote_estimate; + fpinfo->fetch_size = fpinfo_o->fetch_size; + + /* Merge the table level options from either side of the join. */ + if (fpinfo_i) + { + /* + * We'll prefer to use remote estimates for this join if any table + * from either side of the join is using remote estimates. This is + * most likely going to be preferred since they're already willing to + * pay the price of a round trip to get the remote EXPLAIN. In any + * case it's not entirely clear how we might otherwise handle this + * best. + */ + fpinfo->use_remote_estimate = fpinfo_o->use_remote_estimate || + fpinfo_i->use_remote_estimate; + + /* + * Set fetch size to maximum of the joining sides, since we are + * expecting the rows returned by the join to be proportional to the + * relation sizes. + */ + fpinfo->fetch_size = Max(fpinfo_o->fetch_size, fpinfo_i->fetch_size); + } +} + +/* * postgresGetForeignJoinPaths * Add possible ForeignPath to joinrel, if join is safe to push down. */ @@ -4715,18 +4781,6 @@ foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel) fpinfo->pushdown_safe = true; /* - * If user is willing to estimate cost for a scan using EXPLAIN, he - * intends to estimate scans on that relation more accurately. Then, it - * makes sense to estimate the cost of the grouping on that relation more - * accurately using EXPLAIN. - */ - fpinfo->use_remote_estimate = ofpinfo->use_remote_estimate; - - /* Copy startup and tuple cost as is from underneath input rel's fpinfo */ - fpinfo->fdw_startup_cost = ofpinfo->fdw_startup_cost; - fpinfo->fdw_tuple_cost = ofpinfo->fdw_tuple_cost; - - /* * Set cached relation costs to some negative value, so that we can detect * when they are set to some sensible costs, during one (usually the * first) of the calls to estimate_path_cost_size(). @@ -4734,9 +4788,6 @@ foreign_grouping_ok(PlannerInfo *root, RelOptInfo *grouped_rel) fpinfo->rel_startup_cost = -1; fpinfo->rel_total_cost = -1; - /* Set fetch size same as that of underneath input rel's fpinfo */ - fpinfo->fetch_size = ofpinfo->fetch_size; - /* * Set the string describing this grouped relation to be used in EXPLAIN * output of corresponding ForeignScan. @@ -4812,13 +4863,13 @@ add_foreign_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel, fpinfo->outerrel = input_rel; /* - * Copy foreign table, foreign server, user mapping, shippable extensions - * etc. details from the input relation's fpinfo. + * Copy foreign table, foreign server, user mapping, FDW options etc. + * details from the input relation's fpinfo. */ fpinfo->table = ifpinfo->table; fpinfo->server = ifpinfo->server; fpinfo->user = ifpinfo->user; - fpinfo->shippable_extensions = ifpinfo->shippable_extensions; + merge_fdw_options(fpinfo, ifpinfo , NULL); /* Assess if it is safe to push down aggregation and grouping. */ if (!foreign_grouping_ok(root, grouped_rel)) |