diff options
Diffstat (limited to 'contrib')
| -rw-r--r-- | contrib/file_fdw/file_fdw.c | 161 |
1 files changed, 128 insertions, 33 deletions
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c index 29f203c6f10..e8907709bd9 100644 --- a/contrib/file_fdw/file_fdw.c +++ b/contrib/file_fdw/file_fdw.c @@ -26,6 +26,8 @@ #include "nodes/makefuncs.h" #include "optimizer/cost.h" #include "optimizer/pathnode.h" +#include "optimizer/planmain.h" +#include "optimizer/restrictinfo.h" #include "utils/rel.h" PG_MODULE_MAGIC; @@ -48,7 +50,7 @@ struct FileFdwOption * Note: If you are adding new option for user mapping, you need to modify * fileGetOptions(), which currently doesn't bother to look at user mappings. */ -static struct FileFdwOption valid_options[] = { +static const struct FileFdwOption valid_options[] = { /* File options */ {"filename", ForeignTableRelationId}, @@ -72,6 +74,17 @@ static struct FileFdwOption valid_options[] = { }; /* + * FDW-specific information for RelOptInfo.fdw_private. + */ +typedef struct FileFdwPlanState +{ + char *filename; /* file to read */ + List *options; /* merged COPY options, excluding filename */ + BlockNumber pages; /* estimate of file's physical size */ + double ntuples; /* estimate of number of rows in file */ +} FileFdwPlanState; + +/* * FDW-specific information for ForeignScanState.fdw_state. */ typedef struct FileFdwExecutionState @@ -93,9 +106,18 @@ PG_FUNCTION_INFO_V1(file_fdw_validator); /* * FDW callback routines */ -static void filePlanForeignScan(Oid foreigntableid, - PlannerInfo *root, - RelOptInfo *baserel); +static void fileGetForeignRelSize(PlannerInfo *root, + RelOptInfo *baserel, + Oid foreigntableid); +static void fileGetForeignPaths(PlannerInfo *root, + RelOptInfo *baserel, + Oid foreigntableid); +static ForeignScan *fileGetForeignPlan(PlannerInfo *root, + RelOptInfo *baserel, + Oid foreigntableid, + ForeignPath *best_path, + List *tlist, + List *scan_clauses); static void fileExplainForeignScan(ForeignScanState *node, ExplainState *es); static void fileBeginForeignScan(ForeignScanState *node, int eflags); static TupleTableSlot *fileIterateForeignScan(ForeignScanState *node); @@ -109,8 +131,10 @@ static bool is_valid_option(const char *option, Oid context); static void fileGetOptions(Oid foreigntableid, char **filename, List **other_options); static List *get_file_fdw_attribute_options(Oid relid); +static void estimate_size(PlannerInfo *root, RelOptInfo *baserel, + FileFdwPlanState *fdw_private); static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel, - const char *filename, + FileFdwPlanState *fdw_private, Cost *startup_cost, Cost *total_cost); @@ -123,7 +147,9 @@ file_fdw_handler(PG_FUNCTION_ARGS) { FdwRoutine *fdwroutine = makeNode(FdwRoutine); - fdwroutine->PlanForeignScan = filePlanForeignScan; + fdwroutine->GetForeignRelSize = fileGetForeignRelSize; + fdwroutine->GetForeignPaths = fileGetForeignPaths; + fdwroutine->GetForeignPlan = fileGetForeignPlan; fdwroutine->ExplainForeignScan = fileExplainForeignScan; fdwroutine->BeginForeignScan = fileBeginForeignScan; fdwroutine->IterateForeignScan = fileIterateForeignScan; @@ -177,7 +203,7 @@ file_fdw_validator(PG_FUNCTION_ARGS) if (!is_valid_option(def->defname, catalog)) { - struct FileFdwOption *opt; + const struct FileFdwOption *opt; StringInfoData buf; /* @@ -249,7 +275,7 @@ file_fdw_validator(PG_FUNCTION_ARGS) static bool is_valid_option(const char *option, Oid context) { - struct FileFdwOption *opt; + const struct FileFdwOption *opt; for (opt = valid_options; opt->optname; opt++) { @@ -381,7 +407,31 @@ get_file_fdw_attribute_options(Oid relid) } /* - * filePlanForeignScan + * fileGetForeignRelSize + * Obtain relation size estimates for a foreign table + */ +static void +fileGetForeignRelSize(PlannerInfo *root, + RelOptInfo *baserel, + Oid foreigntableid) +{ + FileFdwPlanState *fdw_private; + + /* + * Fetch options. We only need filename at this point, but we might + * as well get everything and not need to re-fetch it later in planning. + */ + fdw_private = (FileFdwPlanState *) palloc(sizeof(FileFdwPlanState)); + fileGetOptions(foreigntableid, + &fdw_private->filename, &fdw_private->options); + baserel->fdw_private = (void *) fdw_private; + + /* Estimate relation size */ + estimate_size(root, baserel, fdw_private); +} + +/* + * fileGetForeignPaths * 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 @@ -389,20 +439,16 @@ get_file_fdw_attribute_options(Oid relid) * the data file. */ static void -filePlanForeignScan(Oid foreigntableid, - PlannerInfo *root, - RelOptInfo *baserel) +fileGetForeignPaths(PlannerInfo *root, + RelOptInfo *baserel, + Oid foreigntableid) { - char *filename; - List *options; + FileFdwPlanState *fdw_private = (FileFdwPlanState *) baserel->fdw_private; Cost startup_cost; Cost total_cost; - /* Fetch options --- we only need filename at this point */ - fileGetOptions(foreigntableid, &filename, &options); - - /* Estimate costs and update baserel->rows */ - estimate_costs(root, baserel, filename, + /* Estimate costs */ + estimate_costs(root, baserel, fdw_private, &startup_cost, &total_cost); /* Create a ForeignPath node and add it as only possible path */ @@ -423,6 +469,37 @@ filePlanForeignScan(Oid foreigntableid, } /* + * fileGetForeignPlan + * Create a ForeignScan plan node for scanning the foreign table + */ +static ForeignScan * +fileGetForeignPlan(PlannerInfo *root, + RelOptInfo *baserel, + Oid foreigntableid, + ForeignPath *best_path, + List *tlist, + List *scan_clauses) +{ + Index scan_relid = baserel->relid; + + /* + * We have no native ability to evaluate restriction clauses, so we just + * put all the scan_clauses into the plan node's qual list for the + * executor to check. So all we have to do here is strip RestrictInfo + * nodes from the clauses and ignore pseudoconstants (which will be + * handled elsewhere). + */ + scan_clauses = extract_actual_clauses(scan_clauses, false); + + /* Create the ForeignScan node */ + return make_foreignscan(tlist, + scan_clauses, + scan_relid, + NIL, /* no expressions to evaluate */ + NIL); /* no private state either */ +} + +/* * fileExplainForeignScan * Produce extra output for EXPLAIN */ @@ -568,38 +645,38 @@ fileReScanForeignScan(ForeignScanState *node) } /* - * Estimate costs of scanning a foreign table. + * Estimate size of a foreign table. * - * In addition to setting *startup_cost and *total_cost, this should - * update baserel->rows. + * The main result is returned in baserel->rows. We also set + * fdw_private->pages and fdw_private->ntuples for later use in the cost + * calculation. */ static void -estimate_costs(PlannerInfo *root, RelOptInfo *baserel, - const char *filename, - Cost *startup_cost, Cost *total_cost) +estimate_size(PlannerInfo *root, RelOptInfo *baserel, + FileFdwPlanState *fdw_private) { struct stat stat_buf; BlockNumber pages; int tuple_width; double ntuples; double nrows; - Cost run_cost = 0; - Cost cpu_per_tuple; /* * Get size of the file. It might not be there at plan time, though, in * which case we have to use a default estimate. */ - if (stat(filename, &stat_buf) < 0) + if (stat(fdw_private->filename, &stat_buf) < 0) stat_buf.st_size = 10 * BLCKSZ; /* - * Convert size to pages for use in I/O cost estimate below. + * Convert size to pages for use in I/O cost estimate later. */ pages = (stat_buf.st_size + (BLCKSZ - 1)) / BLCKSZ; if (pages < 1) pages = 1; + fdw_private->pages = pages; + /* * Estimate the number of tuples in the file. We back into this estimate * using the planner's idea of the relation width; which is bogus if not @@ -611,6 +688,8 @@ estimate_costs(PlannerInfo *root, RelOptInfo *baserel, ntuples = clamp_row_est((double) stat_buf.st_size / (double) tuple_width); + fdw_private->ntuples = ntuples; + /* * Now estimate the number of rows returned by the scan after applying the * baserestrictinfo quals. This is pretty bogus too, since the planner @@ -627,12 +706,28 @@ estimate_costs(PlannerInfo *root, RelOptInfo *baserel, /* Save the output-rows estimate for the planner */ baserel->rows = nrows; +} + +/* + * Estimate costs of scanning a foreign table. + * + * Results are returned in *startup_cost and *total_cost. + */ +static void +estimate_costs(PlannerInfo *root, RelOptInfo *baserel, + FileFdwPlanState *fdw_private, + Cost *startup_cost, Cost *total_cost) +{ + BlockNumber pages = fdw_private->pages; + double ntuples = fdw_private->ntuples; + Cost run_cost = 0; + Cost cpu_per_tuple; /* - * Now estimate costs. We estimate costs almost the same way as - * cost_seqscan(), thus assuming that I/O costs are equivalent to a - * regular table file of the same size. However, we take per-tuple CPU - * costs as 10x of a seqscan, to account for the cost of parsing records. + * We estimate costs almost the same way as cost_seqscan(), thus assuming + * that I/O costs are equivalent to a regular table file of the same size. + * However, we take per-tuple CPU costs as 10x of a seqscan, to account + * for the cost of parsing records. */ run_cost += seq_page_cost * pages; |