file_fdw.c File Reference

#include "postgres.h"
#include <sys/stat.h>
#include <unistd.h>
#include "access/htup_details.h"
#include "access/reloptions.h"
#include "access/sysattr.h"
#include "access/table.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_foreign_table.h"
#include "commands/copy.h"
#include "commands/defrem.h"
#include "commands/explain.h"
#include "commands/vacuum.h"
#include "foreign/fdwapi.h"
#include "foreign/foreign.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "optimizer/optimizer.h"
#include "optimizer/pathnode.h"
#include "optimizer/planmain.h"
#include "optimizer/restrictinfo.h"
#include "utils/acl.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/sampling.h"
#include "utils/varlena.h"

Include dependency graph for file_fdw.c:

Go to the source code of this file.

Data Structures
struct	FileFdwOption
struct	FileFdwPlanState
struct	FileFdwExecutionState

Typedefs
typedef struct FileFdwPlanState	FileFdwPlanState
typedef struct FileFdwExecutionState	FileFdwExecutionState

Functions
	PG_FUNCTION_INFO_V1 (file_fdw_handler)
	PG_FUNCTION_INFO_V1 (file_fdw_validator)
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, Plan *outer_plan)
static void	fileExplainForeignScan (ForeignScanState *node, ExplainState *es)
static void	fileBeginForeignScan (ForeignScanState *node, int eflags)
static TupleTableSlot *	fileIterateForeignScan (ForeignScanState *node)
static void	fileReScanForeignScan (ForeignScanState *node)
static void	fileEndForeignScan (ForeignScanState *node)
static bool	fileAnalyzeForeignTable (Relation relation, AcquireSampleRowsFunc *func, BlockNumber *totalpages)
static bool	fileIsForeignScanParallelSafe (PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
static bool	is_valid_option (const char *option, Oid context)
static void	fileGetOptions (Oid foreigntableid, char **filename, bool *is_program, List **other_options)
static List *	get_file_fdw_attribute_options (Oid relid)
static bool	check_selective_binary_conversion (RelOptInfo *baserel, Oid foreigntableid, List **columns)
static void	estimate_size (PlannerInfo *root, RelOptInfo *baserel, FileFdwPlanState *fdw_private)
static void	estimate_costs (PlannerInfo *root, RelOptInfo *baserel, FileFdwPlanState *fdw_private, Cost *startup_cost, Cost *total_cost)
static int	file_acquire_sample_rows (Relation onerel, int elevel, HeapTuple *rows, int targrows, double *totalrows, double *totaldeadrows)
Datum	file_fdw_handler (PG_FUNCTION_ARGS)
Datum	file_fdw_validator (PG_FUNCTION_ARGS)

Variables
	PG_MODULE_MAGIC
static const struct FileFdwOption	valid_options []

Typedef Documentation

FileFdwExecutionState

typedef struct FileFdwExecutionState FileFdwExecutionState

FileFdwPlanState

typedef struct FileFdwPlanState FileFdwPlanState

Function Documentation

check_selective_binary_conversion()

static bool check_selective_binary_conversion ( RelOptInfo *  baserel, Oid  foreigntableid, List **  columns  )

static

Definition at line 873 of file file_fdw.c.

{
    ForeignTable *table;
    ListCell   *lc;
    Relation    rel;
    TupleDesc   tupleDesc;
    int         attidx;
    Bitmapset  *attrs_used = NULL;
    bool        has_wholerow = false;
    int         numattrs;
    int         i;
 
    *columns = NIL;             /* default result */
 
    /*
     * Check format of the file.  If binary format, this is irrelevant.
     */
    table = GetForeignTable(foreigntableid);
    foreach(lc, table->options)
    {
        DefElem    *def = (DefElem *) lfirst(lc);
 
        if (strcmp(def->defname, "format") == 0)
        {
            char       *format = defGetString(def);
 
            if (strcmp(format, "binary") == 0)
                return false;
            break;
        }
    }
 
    /* Collect all the attributes needed for joins or final output. */
    pull_varattnos((Node *) baserel->reltarget->exprs, baserel->relid,
                   &attrs_used);
 
    /* Add all the attributes used by restriction clauses. */
    foreach(lc, baserel->baserestrictinfo)
    {
        RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
 
        pull_varattnos((Node *) rinfo->clause, baserel->relid,
                       &attrs_used);
    }
 
    /* Convert attribute numbers to column names. */
    rel = table_open(foreigntableid, AccessShareLock);
    tupleDesc = RelationGetDescr(rel);
 
    attidx = -1;
    while ((attidx = bms_next_member(attrs_used, attidx)) >= 0)
    {
        /* attidx is zero-based, attnum is the normal attribute number */
        AttrNumber  attnum = attidx + FirstLowInvalidHeapAttributeNumber;
 
        if (attnum == 0)
        {
            has_wholerow = true;
            break;
        }
 
        /* Ignore system attributes. */
        if (attnum < 0)
            continue;
 
        /* Get user attributes. */
        if (attnum > 0)
        {
            Form_pg_attribute attr = TupleDescAttr(tupleDesc, attnum - 1);
            char       *attname = NameStr(attr->attname);
 
            /* Skip dropped attributes (probably shouldn't see any here). */
            if (attr->attisdropped)
                continue;
 
            /*
             * Skip generated columns (COPY won't accept them in the column
             * list)
             */
            if (attr->attgenerated)
                continue;
            *columns = lappend(*columns, makeString(pstrdup(attname)));
        }
    }
 
    /* Count non-dropped user attributes while we have the tupdesc. */
    numattrs = 0;
    for (i = 0; i < tupleDesc->natts; i++)
    {
        Form_pg_attribute attr = TupleDescAttr(tupleDesc, i);
 
        if (attr->attisdropped)
            continue;
        numattrs++;
    }
 
    table_close(rel, AccessShareLock);
 
    /* If there's a whole-row reference, fail: we need all the columns. */
    if (has_wholerow)
    {
        *columns = NIL;
        return false;
    }
 
    /* If all the user attributes are needed, fail. */
    if (numattrs == list_length(*columns))
    {
        *columns = NIL;
        return false;
    }
 
    return true;
}

References AccessShareLock, attname, attnum, RelOptInfo::baserestrictinfo, bms_next_member(), RestrictInfo::clause, defGetString(), DefElem::defname, PathTarget::exprs, FirstLowInvalidHeapAttributeNumber, format, GetForeignTable(), i, lappend(), lfirst, list_length(), makeString(), NameStr, TupleDescData::natts, NIL, ForeignTable::options, pstrdup(), pull_varattnos(), RelationGetDescr, RelOptInfo::relid, RelOptInfo::reltarget, table_close(), table_open(), and TupleDescAttr.

Referenced by fileGetForeignPaths().

estimate_costs()

static void estimate_costs ( PlannerInfo *  root, RelOptInfo *  baserel, FileFdwPlanState *  fdw_private, Cost *  startup_cost, Cost *  total_cost  )

static

Definition at line 1079 of file file_fdw.c.

{
    BlockNumber pages = fdw_private->pages;
    double      ntuples = fdw_private->ntuples;
    Cost        run_cost = 0;
    Cost        cpu_per_tuple;
 
    /*
     * 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.
     *
     * In the case of a program source, this calculation is even more divorced
     * from reality, but we have no good alternative; and it's not clear that
     * the numbers we produce here matter much anyway, since there's only one
     * access path for the rel.
     */
    run_cost += seq_page_cost * pages;
 
    *startup_cost = baserel->baserestrictcost.startup;
    cpu_per_tuple = cpu_tuple_cost * 10 + baserel->baserestrictcost.per_tuple;
    run_cost += cpu_per_tuple * ntuples;
    *total_cost = *startup_cost + run_cost;
}

References RelOptInfo::baserestrictcost, cpu_tuple_cost, FileFdwPlanState::ntuples, FileFdwPlanState::pages, QualCost::per_tuple, seq_page_cost, and QualCost::startup.

Referenced by fileGetForeignPaths().

estimate_size()

static void estimate_size ( PlannerInfo *  root, RelOptInfo *  baserel, FileFdwPlanState *  fdw_private  )

static

Definition at line 998 of file file_fdw.c.

{
    struct stat stat_buf;
    BlockNumber pages;
    double      ntuples;
    double      nrows;
 
    /*
     * Get size of the file.  It might not be there at plan time, though, in
     * which case we have to use a default estimate.  We also have to fall
     * back to the default if using a program as the input.
     */
    if (fdw_private->is_program || stat(fdw_private->filename, &stat_buf) < 0)
        stat_buf.st_size = 10 * BLCKSZ;
 
    /*
     * 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.
     */
    if (baserel->tuples >= 0 && baserel->pages > 0)
    {
        /*
         * We have # of pages and # of tuples from pg_class (that is, from a
         * previous ANALYZE), so compute a tuples-per-page estimate and scale
         * that by the current file size.
         */
        double      density;
 
        density = baserel->tuples / (double) baserel->pages;
        ntuples = clamp_row_est(density * (double) pages);
    }
    else
    {
        /*
         * Otherwise we have to fake it.  We back into this estimate using the
         * planner's idea of the relation width; which is bogus if not all
         * columns are being read, not to mention that the text representation
         * of a row probably isn't the same size as its internal
         * representation.  Possibly we could do something better, but the
         * real answer to anyone who complains is "ANALYZE" ...
         */
        int         tuple_width;
 
        tuple_width = MAXALIGN(baserel->reltarget->width) +
            MAXALIGN(SizeofHeapTupleHeader);
        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.
     */
    nrows = ntuples *
        clauselist_selectivity(root,
                               baserel->baserestrictinfo,
                               0,
                               JOIN_INNER,
                               NULL);
 
    nrows = clamp_row_est(nrows);
 
    /* Save the output-rows estimate for the planner */
    baserel->rows = nrows;
}

References RelOptInfo::baserestrictinfo, clamp_row_est(), clauselist_selectivity(), FileFdwPlanState::filename, FileFdwPlanState::is_program, JOIN_INNER, MAXALIGN, FileFdwPlanState::ntuples, FileFdwPlanState::pages, RelOptInfo::pages, RelOptInfo::reltarget, RelOptInfo::rows, SizeofHeapTupleHeader, stat::st_size, RelOptInfo::tuples, and PathTarget::width.

Referenced by fileGetForeignRelSize().

file_acquire_sample_rows()

static int file_acquire_sample_rows ( Relation  onerel, int  elevel, HeapTuple *  rows, int  targrows, double *  totalrows, double *  totaldeadrows  )

static

Definition at line 1122 of file file_fdw.c.

{
    int         numrows = 0;
    double      rowstoskip = -1;    /* -1 means not set yet */
    ReservoirStateData rstate;
    TupleDesc   tupDesc;
    Datum      *values;
    bool       *nulls;
    bool        found;
    char       *filename;
    bool        is_program;
    List       *options;
    CopyFromState cstate;
    ErrorContextCallback errcallback;
    MemoryContext oldcontext = CurrentMemoryContext;
    MemoryContext tupcontext;
 
    Assert(onerel);
    Assert(targrows > 0);
 
    tupDesc = RelationGetDescr(onerel);
    values = (Datum *) palloc(tupDesc->natts * sizeof(Datum));
    nulls = (bool *) palloc(tupDesc->natts * sizeof(bool));
 
    /* Fetch options of foreign table */
    fileGetOptions(RelationGetRelid(onerel), &filename, &is_program, &options);
 
    /*
     * Create CopyState from FDW options.
     */
    cstate = BeginCopyFrom(NULL, onerel, NULL, filename, is_program, NULL, NIL,
                           options);
 
    /*
     * Use per-tuple memory context to prevent leak of memory used to read
     * rows from the file with Copy routines.
     */
    tupcontext = AllocSetContextCreate(CurrentMemoryContext,
                                       "file_fdw temporary context",
                                       ALLOCSET_DEFAULT_SIZES);
 
    /* Prepare for sampling rows */
    reservoir_init_selection_state(&rstate, targrows);
 
    /* Set up callback to identify error line number. */
    errcallback.callback = CopyFromErrorCallback;
    errcallback.arg = (void *) cstate;
    errcallback.previous = error_context_stack;
    error_context_stack = &errcallback;
 
    *totalrows = 0;
    *totaldeadrows = 0;
    for (;;)
    {
        /* Check for user-requested abort or sleep */
        vacuum_delay_point();
 
        /* Fetch next row */
        MemoryContextReset(tupcontext);
        MemoryContextSwitchTo(tupcontext);
 
        found = NextCopyFrom(cstate, NULL, values, nulls);
 
        MemoryContextSwitchTo(oldcontext);
 
        if (!found)
            break;
 
        /*
         * The first targrows sample rows are simply copied into the
         * reservoir.  Then we start replacing tuples in the sample until we
         * reach the end of the relation. This algorithm is from Jeff Vitter's
         * paper (see more info in commands/analyze.c).
         */
        if (numrows < targrows)
        {
            rows[numrows++] = heap_form_tuple(tupDesc, values, nulls);
        }
        else
        {
            /*
             * t in Vitter's paper is the number of records already processed.
             * If we need to compute a new S value, we must use the
             * not-yet-incremented value of totalrows as t.
             */
            if (rowstoskip < 0)
                rowstoskip = reservoir_get_next_S(&rstate, *totalrows, targrows);
 
            if (rowstoskip <= 0)
            {
                /*
                 * Found a suitable tuple, so save it, replacing one old tuple
                 * at random
                 */
                int         k = (int) (targrows * sampler_random_fract(&rstate.randstate));
 
                Assert(k >= 0 && k < targrows);
                heap_freetuple(rows[k]);
                rows[k] = heap_form_tuple(tupDesc, values, nulls);
            }
 
            rowstoskip -= 1;
        }
 
        *totalrows += 1;
    }
 
    /* Remove error callback. */
    error_context_stack = errcallback.previous;
 
    /* Clean up. */
    MemoryContextDelete(tupcontext);
 
    EndCopyFrom(cstate);
 
    pfree(values);
    pfree(nulls);
 
    /*
     * Emit some interesting relation info
     */
    ereport(elevel,
            (errmsg("\"%s\": file contains %.0f rows; "
                    "%d rows in sample",
                    RelationGetRelationName(onerel),
                    *totalrows, numrows)));
 
    return numrows;
}

References ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, ErrorContextCallback::arg, Assert(), BeginCopyFrom(), ErrorContextCallback::callback, CopyFromErrorCallback(), CurrentMemoryContext, EndCopyFrom(), ereport, errmsg(), error_context_stack, fileGetOptions(), filename, heap_form_tuple(), heap_freetuple(), MemoryContextDelete(), MemoryContextReset(), MemoryContextSwitchTo(), TupleDescData::natts, NextCopyFrom(), NIL, options, palloc(), pfree(), ErrorContextCallback::previous, ReservoirStateData::randstate, RelationGetDescr, RelationGetRelationName, RelationGetRelid, reservoir_get_next_S(), reservoir_init_selection_state(), sampler_random_fract(), vacuum_delay_point(), and values.

Referenced by fileAnalyzeForeignTable().

file_fdw_handler()

Datum file_fdw_handler

(

PG_FUNCTION_ARGS

)

Definition at line 173 of file file_fdw.c.

{
    FdwRoutine *fdwroutine = makeNode(FdwRoutine);
 
    fdwroutine->GetForeignRelSize = fileGetForeignRelSize;
    fdwroutine->GetForeignPaths = fileGetForeignPaths;
    fdwroutine->GetForeignPlan = fileGetForeignPlan;
    fdwroutine->ExplainForeignScan = fileExplainForeignScan;
    fdwroutine->BeginForeignScan = fileBeginForeignScan;
    fdwroutine->IterateForeignScan = fileIterateForeignScan;
    fdwroutine->ReScanForeignScan = fileReScanForeignScan;
    fdwroutine->EndForeignScan = fileEndForeignScan;
    fdwroutine->AnalyzeForeignTable = fileAnalyzeForeignTable;
    fdwroutine->IsForeignScanParallelSafe = fileIsForeignScanParallelSafe;
 
    PG_RETURN_POINTER(fdwroutine);
}

References FdwRoutine::AnalyzeForeignTable, FdwRoutine::BeginForeignScan, FdwRoutine::EndForeignScan, FdwRoutine::ExplainForeignScan, fileAnalyzeForeignTable(), fileBeginForeignScan(), fileEndForeignScan(), fileExplainForeignScan(), fileGetForeignPaths(), fileGetForeignPlan(), fileGetForeignRelSize(), fileIsForeignScanParallelSafe(), fileIterateForeignScan(), fileReScanForeignScan(), FdwRoutine::GetForeignPaths, FdwRoutine::GetForeignPlan, FdwRoutine::GetForeignRelSize, FdwRoutine::IsForeignScanParallelSafe, FdwRoutine::IterateForeignScan, makeNode, PG_RETURN_POINTER, and FdwRoutine::ReScanForeignScan.

file_fdw_validator()

Datum file_fdw_validator

(

PG_FUNCTION_ARGS

)

Definition at line 198 of file file_fdw.c.

{
    List       *options_list = untransformRelOptions(PG_GETARG_DATUM(0));
    Oid         catalog = PG_GETARG_OID(1);
    char       *filename = NULL;
    DefElem    *force_not_null = NULL;
    DefElem    *force_null = NULL;
    List       *other_options = NIL;
    ListCell   *cell;
 
    /*
     * Check that only options supported by file_fdw, and allowed for the
     * current object type, are given.
     */
    foreach(cell, options_list)
    {
        DefElem    *def = (DefElem *) lfirst(cell);
 
        if (!is_valid_option(def->defname, catalog))
        {
            const struct FileFdwOption *opt;
            const char *closest_match;
            ClosestMatchState match_state;
            bool        has_valid_options = false;
 
            /*
             * Unknown option specified, complain about it. Provide a hint
             * with a valid option that looks similar, if there is one.
             */
            initClosestMatch(&match_state, def->defname, 4);
            for (opt = valid_options; opt->optname; opt++)
            {
                if (catalog == opt->optcontext)
                {
                    has_valid_options = true;
                    updateClosestMatch(&match_state, opt->optname);
                }
            }
 
            closest_match = getClosestMatch(&match_state);
            ereport(ERROR,
                    (errcode(ERRCODE_FDW_INVALID_OPTION_NAME),
                     errmsg("invalid option \"%s\"", def->defname),
                     has_valid_options ? closest_match ?
                     errhint("Perhaps you meant the option \"%s\".",
                             closest_match) : 0 :
                     errhint("There are no valid options in this context.")));
        }
 
        /*
         * Separate out filename, program, and column-specific options, since
         * ProcessCopyOptions won't accept them.
         */
        if (strcmp(def->defname, "filename") == 0 ||
            strcmp(def->defname, "program") == 0)
        {
            if (filename)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options")));
 
            /*
             * Check permissions for changing which file or program is used by
             * the file_fdw.
             *
             * Only members of the role 'pg_read_server_files' are allowed to
             * set the 'filename' option of a file_fdw foreign table, while
             * only members of the role 'pg_execute_server_program' are
             * allowed to set the 'program' option.  This is because we don't
             * want regular users to be able to control which file gets read
             * or which program gets executed.
             *
             * Putting this sort of permissions check in a validator is a bit
             * of a crock, but there doesn't seem to be any other place that
             * can enforce the check more cleanly.
             *
             * Note that the valid_options[] array disallows setting filename
             * and program at any options level other than foreign table ---
             * otherwise there'd still be a security hole.
             */
            if (strcmp(def->defname, "filename") == 0 &&
                !has_privs_of_role(GetUserId(), ROLE_PG_READ_SERVER_FILES))
                ereport(ERROR,
                        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                         errmsg("permission denied to set the \"%s\" option of a file_fdw foreign table",
                                "filename"),
                         errdetail("Only roles with privileges of the \"%s\" role may set this option.",
                                   "pg_read_server_files")));
 
            if (strcmp(def->defname, "program") == 0 &&
                !has_privs_of_role(GetUserId(), ROLE_PG_EXECUTE_SERVER_PROGRAM))
                ereport(ERROR,
                        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                         errmsg("permission denied to set the \"%s\" option of a file_fdw foreign table",
                                "program"),
                         errdetail("Only roles with privileges of the \"%s\" role may set this option.",
                                   "pg_execute_server_program")));
 
            filename = defGetString(def);
        }
 
        /*
         * force_not_null is a boolean option; after validation we can discard
         * it - it will be retrieved later in get_file_fdw_attribute_options()
         */
        else if (strcmp(def->defname, "force_not_null") == 0)
        {
            if (force_not_null)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         errhint("Option \"force_not_null\" supplied more than once for a column.")));
            force_not_null = def;
            /* Don't care what the value is, as long as it's a legal boolean */
            (void) defGetBoolean(def);
        }
        /* See comments for force_not_null above */
        else if (strcmp(def->defname, "force_null") == 0)
        {
            if (force_null)
                ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("conflicting or redundant options"),
                         errhint("Option \"force_null\" supplied more than once for a column.")));
            force_null = def;
            (void) defGetBoolean(def);
        }
        else
            other_options = lappend(other_options, def);
    }
 
    /*
     * Now apply the core COPY code's validation logic for more checks.
     */
    ProcessCopyOptions(NULL, NULL, true, other_options);
 
    /*
     * Either filename or program option is required for file_fdw foreign
     * tables.
     */
    if (catalog == ForeignTableRelationId && filename == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_FDW_DYNAMIC_PARAMETER_VALUE_NEEDED),
                 errmsg("either filename or program is required for file_fdw foreign tables")));
 
    PG_RETURN_VOID();
}

References defGetBoolean(), defGetString(), DefElem::defname, ereport, errcode(), errdetail(), errhint(), errmsg(), ERROR, filename, getClosestMatch(), GetUserId(), has_privs_of_role(), initClosestMatch(), is_valid_option(), lappend(), lfirst, match_state, NIL, FileFdwOption::optcontext, FileFdwOption::optname, PG_GETARG_DATUM, PG_GETARG_OID, PG_RETURN_VOID, ProcessCopyOptions(), untransformRelOptions(), updateClosestMatch(), and valid_options.

fileAnalyzeForeignTable()

static bool fileAnalyzeForeignTable ( Relation  relation, AcquireSampleRowsFunc *  func, BlockNumber *  totalpages  )

static

Definition at line 806 of file file_fdw.c.

{
    char       *filename;
    bool        is_program;
    List       *options;
    struct stat stat_buf;
 
    /* Fetch options of foreign table */
    fileGetOptions(RelationGetRelid(relation), &filename, &is_program, &options);
 
    /*
     * If this is a program instead of a file, just return false to skip
     * analyzing the table.  We could run the program and collect stats on
     * whatever it currently returns, but it seems likely that in such cases
     * the output would be too volatile for the stats to be useful.  Maybe
     * there should be an option to enable doing this?
     */
    if (is_program)
        return false;
 
    /*
     * Get size of the file.  (XXX if we fail here, would it be better to just
     * return false to skip analyzing the table?)
     */
    if (stat(filename, &stat_buf) < 0)
        ereport(ERROR,
                (errcode_for_file_access(),
                 errmsg("could not stat file \"%s\": %m",
                        filename)));
 
    /*
     * Convert size to pages.  Must return at least 1 so that we can tell
     * later on that pg_class.relpages is not default.
     */
    *totalpages = (stat_buf.st_size + (BLCKSZ - 1)) / BLCKSZ;
    if (*totalpages < 1)
        *totalpages = 1;
 
    *func = file_acquire_sample_rows;
 
    return true;
}

References ereport, errcode_for_file_access(), errmsg(), ERROR, file_acquire_sample_rows(), fileGetOptions(), filename, options, RelationGetRelid, stat::st_size, and stat.

Referenced by file_fdw_handler().

fileBeginForeignScan()

static void fileBeginForeignScan ( ForeignScanState *  node, int  eflags  )

static

Definition at line 665 of file file_fdw.c.

{
    ForeignScan *plan = (ForeignScan *) node->ss.ps.plan;
    char       *filename;
    bool        is_program;
    List       *options;
    CopyFromState cstate;
    FileFdwExecutionState *festate;
 
    /*
     * Do nothing in EXPLAIN (no ANALYZE) case.  node->fdw_state stays NULL.
     */
    if (eflags & EXEC_FLAG_EXPLAIN_ONLY)
        return;
 
    /* Fetch options of foreign table */
    fileGetOptions(RelationGetRelid(node->ss.ss_currentRelation),
                   &filename, &is_program, &options);
 
    /* Add any options from the plan (currently only convert_selectively) */
    options = list_concat(options, plan->fdw_private);
 
    /*
     * Create CopyState from FDW options.  We always acquire all columns, so
     * as to match the expected ScanTupleSlot signature.
     */
    cstate = BeginCopyFrom(NULL,
                           node->ss.ss_currentRelation,
                           NULL,
                           filename,
                           is_program,
                           NULL,
                           NIL,
                           options);
 
    /*
     * Save state in node->fdw_state.  We must save enough information to call
     * BeginCopyFrom() again.
     */
    festate = (FileFdwExecutionState *) palloc(sizeof(FileFdwExecutionState));
    festate->filename = filename;
    festate->is_program = is_program;
    festate->options = options;
    festate->cstate = cstate;
 
    node->fdw_state = (void *) festate;
}

References BeginCopyFrom(), EXEC_FLAG_EXPLAIN_ONLY, ForeignScan::fdw_private, ForeignScanState::fdw_state, fileGetOptions(), filename, if(), list_concat(), NIL, options, palloc(), PlanState::plan, ScanState::ps, RelationGetRelid, ForeignScanState::ss, and ScanState::ss_currentRelation.

Referenced by file_fdw_handler().

fileEndForeignScan()

static void fileEndForeignScan ( ForeignScanState *  node )

static

Definition at line 792 of file file_fdw.c.

{
    FileFdwExecutionState *festate = (FileFdwExecutionState *) node->fdw_state;
 
    /* if festate is NULL, we are in EXPLAIN; nothing to do */
    if (festate)
        EndCopyFrom(festate->cstate);
}

References FileFdwExecutionState::cstate, EndCopyFrom(), ForeignScanState::fdw_state, and if().

Referenced by file_fdw_handler().

fileExplainForeignScan()

static void fileExplainForeignScan ( ForeignScanState *  node, ExplainState *  es  )

static

Definition at line 633 of file file_fdw.c.

{
    char       *filename;
    bool        is_program;
    List       *options;
 
    /* Fetch options --- we only need filename and is_program at this point */
    fileGetOptions(RelationGetRelid(node->ss.ss_currentRelation),
                   &filename, &is_program, &options);
 
    if (is_program)
        ExplainPropertyText("Foreign Program", filename, es);
    else
        ExplainPropertyText("Foreign File", filename, es);
 
    /* Suppress file size if we're not showing cost details */
    if (es->costs)
    {
        struct stat stat_buf;
 
        if (!is_program &&
            stat(filename, &stat_buf) == 0)
            ExplainPropertyInteger("Foreign File Size", "b",
                                   (int64) stat_buf.st_size, es);
    }
}

References ExplainState::costs, ExplainPropertyInteger(), ExplainPropertyText(), fileGetOptions(), filename, options, RelationGetRelid, ForeignScanState::ss, ScanState::ss_currentRelation, stat::st_size, and stat.

Referenced by file_fdw_handler().

fileGetForeignPaths()

static void fileGetForeignPaths ( PlannerInfo *  root, RelOptInfo *  baserel, Oid  foreigntableid  )

static

Definition at line 545 of file file_fdw.c.

{
    FileFdwPlanState *fdw_private = (FileFdwPlanState *) baserel->fdw_private;
    Cost        startup_cost;
    Cost        total_cost;
    List       *columns;
    List       *coptions = NIL;
 
    /* Decide whether to selectively perform binary conversion */
    if (check_selective_binary_conversion(baserel,
                                          foreigntableid,
                                          &columns))
        coptions = list_make1(makeDefElem("convert_selectively",
                                          (Node *) columns, -1));
 
    /* 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.
     *
     * We don't support pushing join clauses into the quals of this path, but
     * it could still have required parameterization due to LATERAL refs in
     * its tlist.
     */
    add_path(baserel, (Path *)
             create_foreignscan_path(root, baserel,
                                     NULL,  /* default pathtarget */
                                     baserel->rows,
                                     startup_cost,
                                     total_cost,
                                     NIL,   /* no pathkeys */
                                     baserel->lateral_relids,
                                     NULL,  /* no extra plan */
                                     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.
     */
}

References add_path(), check_selective_binary_conversion(), create_foreignscan_path(), estimate_costs(), if(), RelOptInfo::lateral_relids, list_make1, makeDefElem(), NIL, and RelOptInfo::rows.

Referenced by file_fdw_handler().

fileGetForeignPlan()

static ForeignScan * fileGetForeignPlan ( PlannerInfo *  root, RelOptInfo *  baserel, Oid  foreigntableid, ForeignPath *  best_path, List *  tlist, List *  scan_clauses, Plan *  outer_plan  )

static

Definition at line 598 of file file_fdw.c.

{
    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 */
                            best_path->fdw_private,
                            NIL,    /* no custom tlist */
                            NIL,    /* no remote quals */
                            outer_plan);
}

References extract_actual_clauses(), ForeignPath::fdw_private, make_foreignscan(), NIL, and RelOptInfo::relid.

Referenced by file_fdw_handler().

fileGetForeignRelSize()

static void fileGetForeignRelSize ( PlannerInfo *  root, RelOptInfo *  baserel, Oid  foreigntableid  )

static

Definition at line 514 of file file_fdw.c.

{
    FileFdwPlanState *fdw_private;
 
    /*
     * Fetch options.  We only need filename (or program) 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->is_program,
                   &fdw_private->options);
    baserel->fdw_private = (void *) fdw_private;
 
    /* Estimate relation size */
    estimate_size(root, baserel, fdw_private);
}

References estimate_size(), fileGetOptions(), FileFdwPlanState::filename, FileFdwPlanState::is_program, FileFdwPlanState::options, and palloc().

Referenced by file_fdw_handler().

fileGetOptions()

static void fileGetOptions ( Oid  foreigntableid, char **  filename, bool *  is_program, List **  other_options  )

static

Definition at line 370 of file file_fdw.c.

{
    ForeignTable *table;
    ForeignServer *server;
    ForeignDataWrapper *wrapper;
    List       *options;
    ListCell   *lc;
 
    /*
     * Extract options from FDW objects.  We ignore user mappings because
     * file_fdw doesn't have any options that can be specified there.
     *
     * (XXX Actually, given the current contents of valid_options[], there's
     * no point in examining anything except the foreign table's own options.
     * Simplify?)
     */
    table = GetForeignTable(foreigntableid);
    server = GetForeignServer(table->serverid);
    wrapper = GetForeignDataWrapper(server->fdwid);
 
    options = NIL;
    options = list_concat(options, wrapper->options);
    options = list_concat(options, server->options);
    options = list_concat(options, table->options);
    options = list_concat(options, get_file_fdw_attribute_options(foreigntableid));
 
    /*
     * Separate out the filename or program option (we assume there is only
     * one).
     */
    *filename = NULL;
    *is_program = false;
    foreach(lc, options)
    {
        DefElem    *def = (DefElem *) lfirst(lc);
 
        if (strcmp(def->defname, "filename") == 0)
        {
            *filename = defGetString(def);
            options = foreach_delete_current(options, lc);
            break;
        }
        else if (strcmp(def->defname, "program") == 0)
        {
            *filename = defGetString(def);
            *is_program = true;
            options = foreach_delete_current(options, lc);
            break;
        }
    }
 
    /*
     * The validator should have checked that filename or program was included
     * in the options, but check again, just in case.
     */
    if (*filename == NULL)
        elog(ERROR, "either filename or program is required for file_fdw foreign tables");
 
    *other_options = options;
}

References defGetString(), DefElem::defname, elog(), ERROR, ForeignServer::fdwid, filename, foreach_delete_current, get_file_fdw_attribute_options(), GetForeignDataWrapper(), GetForeignServer(), GetForeignTable(), lfirst, list_concat(), NIL, options, ForeignDataWrapper::options, ForeignServer::options, ForeignTable::options, and ForeignTable::serverid.

Referenced by file_acquire_sample_rows(), fileAnalyzeForeignTable(), fileBeginForeignScan(), fileExplainForeignScan(), and fileGetForeignRelSize().

fileIsForeignScanParallelSafe()

static bool fileIsForeignScanParallelSafe ( PlannerInfo *  root, RelOptInfo *  rel, RangeTblEntry *  rte  )

static

Definition at line 857 of file file_fdw.c.

{
    return true;
}

Referenced by file_fdw_handler().

fileIterateForeignScan()

static TupleTableSlot * fileIterateForeignScan ( ForeignScanState *  node )

static

Definition at line 719 of file file_fdw.c.

{
    FileFdwExecutionState *festate = (FileFdwExecutionState *) node->fdw_state;
    EState     *estate = CreateExecutorState();
    ExprContext *econtext;
    MemoryContext oldcontext;
    TupleTableSlot *slot = node->ss.ss_ScanTupleSlot;
    bool        found;
    ErrorContextCallback errcallback;
 
    /* Set up callback to identify error line number. */
    errcallback.callback = CopyFromErrorCallback;
    errcallback.arg = (void *) festate->cstate;
    errcallback.previous = error_context_stack;
    error_context_stack = &errcallback;
 
    /*
     * The protocol for loading a virtual tuple into a slot is first
     * ExecClearTuple, then fill the values/isnull arrays, then
     * ExecStoreVirtualTuple.  If we don't find another row in the file, we
     * just skip the last step, leaving the slot empty as required.
     *
     * We pass ExprContext because there might be a use of the DEFAULT option
     * in COPY FROM, so we may need to evaluate default expressions.
     */
    ExecClearTuple(slot);
    econtext = GetPerTupleExprContext(estate);
 
    /*
     * DEFAULT expressions need to be evaluated in a per-tuple context, so
     * switch in case we are doing that.
     */
    oldcontext = MemoryContextSwitchTo(GetPerTupleMemoryContext(estate));
    found = NextCopyFrom(festate->cstate, econtext,
                         slot->tts_values, slot->tts_isnull);
    if (found)
        ExecStoreVirtualTuple(slot);
 
    /* Switch back to original memory context */
    MemoryContextSwitchTo(oldcontext);
 
    /* Remove error callback. */
    error_context_stack = errcallback.previous;
 
    return slot;
}

References ErrorContextCallback::arg, ErrorContextCallback::callback, CopyFromErrorCallback(), CreateExecutorState(), FileFdwExecutionState::cstate, error_context_stack, ExecClearTuple(), ExecStoreVirtualTuple(), ForeignScanState::fdw_state, GetPerTupleExprContext, GetPerTupleMemoryContext, MemoryContextSwitchTo(), NextCopyFrom(), ErrorContextCallback::previous, ForeignScanState::ss, ScanState::ss_ScanTupleSlot, TupleTableSlot::tts_isnull, and TupleTableSlot::tts_values.

Referenced by file_fdw_handler().

fileReScanForeignScan()

static void fileReScanForeignScan ( ForeignScanState *  node )

static

Definition at line 771 of file file_fdw.c.

{
    FileFdwExecutionState *festate = (FileFdwExecutionState *) node->fdw_state;
 
    EndCopyFrom(festate->cstate);
 
    festate->cstate = BeginCopyFrom(NULL,
                                    node->ss.ss_currentRelation,
                                    NULL,
                                    festate->filename,
                                    festate->is_program,
                                    NULL,
                                    NIL,
                                    festate->options);
}

References BeginCopyFrom(), FileFdwExecutionState::cstate, EndCopyFrom(), ForeignScanState::fdw_state, FileFdwExecutionState::filename, FileFdwExecutionState::is_program, NIL, FileFdwExecutionState::options, ForeignScanState::ss, and ScanState::ss_currentRelation.

Referenced by file_fdw_handler().

get_file_fdw_attribute_options()

static List * get_file_fdw_attribute_options ( Oid  relid )

static

Definition at line 441 of file file_fdw.c.

{
    Relation    rel;
    TupleDesc   tupleDesc;
    AttrNumber  natts;
    AttrNumber  attnum;
    List       *fnncolumns = NIL;
    List       *fncolumns = NIL;
 
    List       *options = NIL;
 
    rel = table_open(relid, AccessShareLock);
    tupleDesc = RelationGetDescr(rel);
    natts = tupleDesc->natts;
 
    /* Retrieve FDW options for all user-defined attributes. */
    for (attnum = 1; attnum <= natts; attnum++)
    {
        Form_pg_attribute attr = TupleDescAttr(tupleDesc, attnum - 1);
        List       *column_options;
        ListCell   *lc;
 
        /* Skip dropped attributes. */
        if (attr->attisdropped)
            continue;
 
        column_options = GetForeignColumnOptions(relid, attnum);
        foreach(lc, column_options)
        {
            DefElem    *def = (DefElem *) lfirst(lc);
 
            if (strcmp(def->defname, "force_not_null") == 0)
            {
                if (defGetBoolean(def))
                {
                    char       *attname = pstrdup(NameStr(attr->attname));
 
                    fnncolumns = lappend(fnncolumns, makeString(attname));
                }
            }
            else if (strcmp(def->defname, "force_null") == 0)
            {
                if (defGetBoolean(def))
                {
                    char       *attname = pstrdup(NameStr(attr->attname));
 
                    fncolumns = lappend(fncolumns, makeString(attname));
                }
            }
            /* maybe in future handle other column options here */
        }
    }
 
    table_close(rel, AccessShareLock);
 
    /*
     * Return DefElem only when some column(s) have force_not_null /
     * force_null options set
     */
    if (fnncolumns != NIL)
        options = lappend(options, makeDefElem("force_not_null", (Node *) fnncolumns, -1));
 
    if (fncolumns != NIL)
        options = lappend(options, makeDefElem("force_null", (Node *) fncolumns, -1));
 
    return options;
}

References AccessShareLock, attname, attnum, defGetBoolean(), DefElem::defname, GetForeignColumnOptions(), lappend(), lfirst, makeDefElem(), makeString(), NameStr, TupleDescData::natts, NIL, options, pstrdup(), RelationGetDescr, table_close(), table_open(), and TupleDescAttr.

Referenced by fileGetOptions().

is_valid_option()

static bool is_valid_option ( const char *  option, Oid  context  )

static

Definition at line 351 of file file_fdw.c.

{
    const struct FileFdwOption *opt;
 
    for (opt = valid_options; opt->optname; opt++)
    {
        if (context == opt->optcontext && strcmp(opt->optname, option) == 0)
            return true;
    }
    return false;
}

References FileFdwOption::optcontext, FileFdwOption::optname, and valid_options.

Referenced by file_fdw_validator().

PG_FUNCTION_INFO_V1() [1/2]

PG_FUNCTION_INFO_V1

(

file_fdw_handler

)

PG_FUNCTION_INFO_V1() [2/2]

PG_FUNCTION_INFO_V1

(

file_fdw_validator

)

Variable Documentation

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 42 of file file_fdw.c.

valid_options

const struct FileFdwOption valid_options[]

static

Initial value:

= {
    
    {"filename", ForeignTableRelationId},
    {"program", ForeignTableRelationId},
 
    
    
    {"format", ForeignTableRelationId},
    {"header", ForeignTableRelationId},
    {"delimiter", ForeignTableRelationId},
    {"quote", ForeignTableRelationId},
    {"escape", ForeignTableRelationId},
    {"null", ForeignTableRelationId},
    {"default", ForeignTableRelationId},
    {"encoding", ForeignTableRelationId},
    {"force_not_null", AttributeRelationId},
    {"force_null", AttributeRelationId},
 
    
 
    
    {NULL, InvalidOid}
}

Definition at line 42 of file file_fdw.c.

Referenced by file_fdw_validator(), and is_valid_option().