Hi Hanada-san,
I'm very sorry for late reply.
(2011/09/20 18:49), Shigeru Hanada wrote:
> I took a look at the patch, and found that it couldn't be applied
> cleanly against HEAD. Please rebase your patch against current HEAD of
> master branch, rather than 9.1beta1.
>
> The wiki pages below would be helpful for you.
> http://wiki.postgresql.org/wiki/Submitting_a_Patch
> http://wiki.postgresql.org/wiki/Creating_Clean_Patches
> http://wiki.postgresql.org/wiki/Reviewing_a_Patch
>
> And it would be easy to use git to follow changes made by other
> developers in master branch.
> http://wiki.postgresql.org/wiki/Working_with_Git
Thank you for the review and the helpful information.
I rebased. Please find attached a patch. I'll add the patch to the next CF.
Changes:
* cleanups and fixes
* addition of the following to ALTER FOREIGN TABLE
ALTER [COLUMN] column SET STATISTICS integer
ALTER [COLUMN] column SET ( n_distinct = val ) (n_distinct only)
ALTER [COLUMN] column RESET ( n_distinct )
* reflection of the force_not_null info in acquiring sample rows
* documentation
Best regards,
Etsuro Fujita
*** a/contrib/file_fdw/file_fdw.c
--- b/contrib/file_fdw/file_fdw.c
***************
*** 15,30 ****
--- 15,42 ----
#include <sys/stat.h>
#include <unistd.h>
+ #include "access/htup.h"
#include "access/reloptions.h"
+ #include "access/transam.h"
#include "catalog/pg_foreign_table.h"
#include "commands/copy.h"
+ #include "commands/dbcommands.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/cost.h"
+ #include "optimizer/plancat.h"
+ #include "parser/parse_relation.h"
+ #include "pgstat.h"
+ #include "utils/attoptcache.h"
+ #include "utils/elog.h"
+ #include "utils/guc.h"
+ #include "utils/lsyscache.h"
+ #include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/syscache.h"
***************
*** 101,106 **** static void fileBeginForeignScan(ForeignScanState *node, int
eflags);
--- 113,119 ----
static TupleTableSlot *fileIterateForeignScan(ForeignScanState *node);
static void fileReScanForeignScan(ForeignScanState *node);
static void fileEndForeignScan(ForeignScanState *node);
+ static void fileAnalyzeForeignTable(Relation onerel, VacuumStmt *vacstmt, int
elevel);
/*
* Helper functions
***************
*** 112,118 **** static List *get_file_fdw_attribute_options(Oid relid);
static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
const char *filename,
Cost *startup_cost, Cost *total_cost);
!
/*
* Foreign-data wrapper handler function: return a struct with pointers
--- 125,132 ----
static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
const char *filename,
Cost *startup_cost, Cost *total_cost);
! static void file_fdw_do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, int
elevel);
! static int file_fdw_acquire_sample_rows(Relation onerel, int elevel,
HeapTuple *rows, int targrows, BlockNumber *totalpages, double *totalrows);
/*
* Foreign-data wrapper handler function: return a struct with pointers
***************
*** 129,134 **** file_fdw_handler(PG_FUNCTION_ARGS)
--- 143,149 ----
fdwroutine->IterateForeignScan = fileIterateForeignScan;
fdwroutine->ReScanForeignScan = fileReScanForeignScan;
fdwroutine->EndForeignScan = fileEndForeignScan;
+ fdwroutine->AnalyzeForeignTable = fileAnalyzeForeignTable;
PG_RETURN_POINTER(fdwroutine);
}
***************
*** 575,580 **** fileReScanForeignScan(ForeignScanState *node)
--- 590,605 ----
}
/*
+ * fileAnalyzeForeignTable
+ * Analyze table
+ */
+ static void
+ fileAnalyzeForeignTable(Relation onerel, VacuumStmt *vacstmt, int elevel)
+ {
+ file_fdw_do_analyze_rel(onerel, vacstmt, elevel);
+ }
+
+ /*
* Estimate costs of scanning a foreign table.
*/
static void
***************
*** 584,590 **** estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
{
struct stat stat_buf;
BlockNumber pages;
! int tuple_width;
double ntuples;
double nrows;
Cost run_cost = 0;
--- 609,616 ----
{
struct stat stat_buf;
BlockNumber pages;
! BlockNumber relpages;
! double reltuples;
double ntuples;
double nrows;
Cost run_cost = 0;
***************
*** 604,619 **** estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
if (pages < 1)
pages = 1;
! /*
! * 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
! * 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.
! * FIXME later.
! */
! tuple_width = MAXALIGN(baserel->width) +
MAXALIGN(sizeof(HeapTupleHeaderData));
! ntuples = clamp_row_est((double) stat_buf.st_size / (double)
tuple_width);
/*
* Now estimate the number of rows returned by the scan after applying
the
--- 630,661 ----
if (pages < 1)
pages = 1;
! relpages = baserel->pages;
! reltuples = baserel->tuples;
! if (relpages > 0)
! {
! double density;
!
! density = reltuples / (double) relpages;
!
! ntuples = clamp_row_est(density * (double) pages);
! }
! else
! {
! int tuple_width;
!
! /*
! * 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
! * 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.
! * FIXME later.
! */
! tuple_width = MAXALIGN(baserel->width) +
MAXALIGN(sizeof(HeapTupleHeaderData));
!
! ntuples = clamp_row_est((double) stat_buf.st_size / (double)
tuple_width);
! }
/*
* Now estimate the number of rows returned by the scan after applying
the
***************
*** 645,647 **** estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
--- 687,1092 ----
run_cost += cpu_per_tuple * ntuples;
*total_cost = *startup_cost + run_cost;
}
+
+ /*
+ * file_fdw_do_analyze_rel() -- analyze one foreign table
+ */
+ static void
+ file_fdw_do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, int elevel)
+ {
+ int i,
+ attr_cnt,
+ tcnt,
+ numrows = 0,
+ targrows;
+ double totalrows = 0;
+ BlockNumber totalpages = 0;
+ HeapTuple *rows;
+ VacAttrStats **vacattrstats;
+ MemoryContext anl_context;
+ MemoryContext caller_context;
+
+ ereport(elevel,
+ (errmsg("analyzing \"%s.%s\"",
+
get_namespace_name(RelationGetNamespace(onerel)),
+ RelationGetRelationName(onerel))));
+
+ /*
+ * Set up a working context so that we can easily free whatever junk
gets
+ * created.
+ */
+ anl_context = AllocSetContextCreate(CurrentMemoryContext,
+
"Analyze",
+
ALLOCSET_DEFAULT_MINSIZE,
+
ALLOCSET_DEFAULT_INITSIZE,
+
ALLOCSET_DEFAULT_MAXSIZE);
+ caller_context = MemoryContextSwitchTo(anl_context);
+
+ /*
+ * Determine which columns to analyze
+ *
+ * Note that system attributes are never analyzed.
+ */
+ if (vacstmt->va_cols != NIL)
+ {
+ ListCell *le;
+
+ vacattrstats = (VacAttrStats **)
palloc(list_length(vacstmt->va_cols) *
+
sizeof(VacAttrStats *));
+ tcnt = 0;
+ foreach(le, vacstmt->va_cols)
+ {
+ char *col = strVal(lfirst(le));
+
+ i = attnameAttNum(onerel, col, false);
+ if (i == InvalidAttrNumber)
+ ereport(ERROR,
+
(errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column \"%s\" of
relation \"%s\" does not exist",
+ col,
RelationGetRelationName(onerel))));
+ vacattrstats[tcnt] = examine_attribute(onerel, i, NULL,
anl_context);
+ if (vacattrstats[tcnt] != NULL)
+ tcnt++;
+ }
+ attr_cnt = tcnt;
+ }
+ else
+ {
+ attr_cnt = onerel->rd_att->natts;
+ vacattrstats = (VacAttrStats **) palloc(attr_cnt *
sizeof(VacAttrStats *));
+ tcnt = 0;
+ for (i = 1; i <= attr_cnt; i++)
+ {
+ vacattrstats[tcnt] = examine_attribute(onerel, i, NULL,
anl_context);
+ if (vacattrstats[tcnt] != NULL)
+ tcnt++;
+ }
+ attr_cnt = tcnt;
+ }
+
+ /*
+ * Quit if no analyzable columns.
+ */
+ if (attr_cnt <= 0)
+ goto cleanup;
+
+ /*
+ * Determine how many rows we need to sample, using the worst case from
+ * all analyzable columns. We use a lower bound of 100 rows to
avoid
+ * possible overflow in Vitter's algorithm.
+ */
+ targrows = 100;
+ for (i = 0; i < attr_cnt; i++)
+ {
+ if (targrows < vacattrstats[i]->minrows)
+ targrows = vacattrstats[i]->minrows;
+ }
+
+ /*
+ * Acquire the sample rows
+ */
+ rows = (HeapTuple *) palloc(targrows * sizeof(HeapTuple));
+ numrows = file_fdw_acquire_sample_rows(onerel, elevel, rows, targrows,
&totalpages, &totalrows);
+
+ /*
+ * Compute the statistics. Temporary results during the
calculations for
+ * each column are stored in a child context. The calc routines are
+ * responsible to make sure that whatever they store into the
VacAttrStats
+ * structure is allocated in anl_context.
+ */
+ if (numrows > 0)
+ {
+ MemoryContext col_context, old_context;
+
+ col_context = AllocSetContextCreate(anl_context,
+
"Analyze Column",
+
ALLOCSET_DEFAULT_MINSIZE,
+
ALLOCSET_DEFAULT_INITSIZE,
+
ALLOCSET_DEFAULT_MAXSIZE);
+ old_context = MemoryContextSwitchTo(col_context);
+
+ for (i = 0; i < attr_cnt; i++)
+ {
+ VacAttrStats *stats = vacattrstats[i];
+ AttributeOpts *aopt =
get_attribute_options(onerel->rd_id, stats->attr->attnum);
+
+ stats->rows = rows;
+ stats->tupDesc = onerel->rd_att;
+ (*stats->compute_stats) (stats,
+
std_fetch_func,
+
numrows,
+
totalrows);
+
+ /*
+ * If the appropriate flavor of the n_distinct option is
+ * specified, override with the corresponding value.
+ */
+ if (aopt != NULL)
+ {
+ float8 n_distinct = aopt->n_distinct;
+
+ if (n_distinct != 0.0)
+ stats->stadistinct = n_distinct;
+ }
+
+ MemoryContextResetAndDeleteChildren(col_context);
+ }
+
+ MemoryContextSwitchTo(old_context);
+ MemoryContextDelete(col_context);
+
+ /*
+ * Emit the completed stats rows into pg_statistic, replacing
any
+ * previous statistics for the target columns. (If there are
stats in
+ * pg_statistic for columns we didn't process, we leave them
alone.)
+ */
+ update_attstats(onerel->rd_id, false, attr_cnt, vacattrstats);
+ }
+
+ /*
+ * Update pages/tuples stats in pg_class.
+ */
+ vac_update_relstats(onerel, totalpages, totalrows, false,
InvalidTransactionId);
+
+ /*
+ * Report ANALYZE to the stats collector, too; likewise, tell it to
adopt
+ * these numbers only if we're not inside a VACUUM that got a better
+ * number. However, a call with inh = true shouldn't reset the
stats.
+ */
+ pgstat_report_analyze(onerel, totalrows, 0);
+
+ /* We skip to here if there were no analyzable columns */
+ cleanup:
+
+ /* Restore current context and release memory */
+ MemoryContextSwitchTo(caller_context);
+ MemoryContextDelete(anl_context);
+ anl_context = NULL;
+ }
+
+ /*
+ * file_fdw_acquire_sample_rows -- acquire a random sample of rows from the
table
+ *
+ * Selected rows are returned in the caller-allocated array rows[], which
+ * must have at least targrows entries.
+ * The actual number of rows selected is returned as the function result.
+ * We also count the number of rows in the table, and return it into
*totalrows.
+ *
+ * The returned list of tuples is in order by physical position in the table.
+ * (We will rely on this later to derive correlation estimates.)
+ */
+ static int
+ file_fdw_acquire_sample_rows(Relation onerel, int elevel, HeapTuple *rows,
int targrows, BlockNumber *totalpages, double *totalrows)
+ {
+ int numrows = 0;
+ double samplerows = 0; /* total # rows collected */
+ double rowstoskip = -1; /* -1 means not set yet */
+ double rstate;
+ HeapTuple tuple;
+ TupleDesc tupDesc;
+ TupleConstr *constr;
+ int natts;
+ int attrChk;
+ Datum *values;
+ bool *nulls;
+ bool found;
+ bool sample_it = false;
+ BlockNumber blknum;
+ OffsetNumber offnum;
+ char *filename;
+ struct stat stat_buf;
+ List *options;
+ ListCell *lc;
+ List *force_notnull = NIL;
+ bool *force_notnull_flags;
+ CopyState cstate;
+ ErrorContextCallback errcontext;
+
+ Assert(onerel);
+ Assert(targrows > 0);
+
+ tupDesc = RelationGetDescr(onerel);
+ constr = tupDesc->constr;
+ natts = tupDesc->natts;
+ values = (Datum *) palloc(tupDesc->natts * sizeof(Datum));
+ nulls = (bool *) palloc(tupDesc->natts * sizeof(bool));
+ force_notnull_flags = (bool *) palloc0(natts * sizeof(bool));
+
+ /* Fetch options of foreign table */
+ fileGetOptions(RelationGetRelid(onerel), &filename, &options);
+
+ foreach(lc, options)
+ {
+ DefElem *def = (DefElem *) lfirst(lc);
+
+ if (strcmp(def->defname, "force_not_null") == 0)
+ {
+ force_notnull = (List *) def->arg;
+ break;
+ }
+ }
+
+ if (force_notnull)
+ {
+ List *attnums;
+ ListCell *cur;
+
+ attnums = CopyGetAttnums(tupDesc, onerel, force_notnull);
+
+ foreach(cur, attnums)
+ {
+ int attnum = lfirst_int(cur);
+
+ force_notnull_flags[attnum - 1] = true;
+ }
+ }
+
+ /*
+ * Get size of the file.
+ */
+ if (stat(filename, &stat_buf) < 0)
+ ereport(ERROR,
+ (errcode_for_file_access(),
+ errmsg("could not stat file \"%s\": %m",
+ filename)));
+
+ /*
+ * Convert size to pages for use in I/O cost estimate.
+ */
+ *totalpages = (stat_buf.st_size + (BLCKSZ - 1)) / BLCKSZ;
+ if (*totalpages < 1)
+ *totalpages = 1;
+
+ /*
+ * Create CopyState from FDW options. We always acquire all columns, so
+ * as to match the expected ScanTupleSlot signature.
+ */
+ cstate = BeginCopyFrom(onerel, filename, NIL, options);
+
+ /* Prepare for sampling rows */
+ rstate = init_selection_state(targrows);
+
+ for (;;)
+ {
+ sample_it = true;
+
+ /* Set up callback to identify error line number. */
+ errcontext.callback = CopyFromErrorCallback;
+ errcontext.arg = (void *) cstate;
+ errcontext.previous = error_context_stack;
+ error_context_stack = &errcontext;
+
+ found = NextCopyFrom(cstate, NULL, values, nulls, NULL);
+
+ /* Remove error callback. */
+ error_context_stack = errcontext.previous;
+
+ if (!found)
+ break;
+
+ tuple = heap_form_tuple(tupDesc, values, nulls);
+
+ if (constr && constr->has_not_null)
+ {
+ for (attrChk = 1; attrChk <= natts; attrChk++)
+ {
+ if (onerel->rd_att->attrs[attrChk -
1]->attnotnull &&
+ !force_notnull_flags[attrChk - 1] &&
+ heap_attisnull(tuple, attrChk))
+ {
+ sample_it = false;
+ break;
+ }
+ }
+ }
+
+ if (!sample_it)
+ {
+ heap_freetuple(tuple);
+ continue;
+ }
+
+ /*
+ * 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 full citation below). It
+ * works by repeatedly computing the number of tuples to skip
+ * before selecting a tuple, which replaces a randomly chosen
+ * element of the reservoir (current set of tuples). At all
+ * times the reservoir is a true random sample of the tuples
+ * we've passed over so far, so when we fall off the end of
+ * the relation we're done.
+ */
+ if (numrows < targrows)
+ {
+ blknum = (BlockNumber) samplerows / MaxOffsetNumber;
+ offnum = (OffsetNumber) samplerows % MaxOffsetNumber +
1;
+ ItemPointerSet(&tuple->t_self, blknum, offnum);
+ rows[numrows++] = heap_copytuple(tuple);
+ }
+ 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 samplerows
as
+ * t.
+ */
+ if (rowstoskip < 0)
+ rowstoskip = get_next_S(samplerows, targrows,
&rstate);
+
+ if (rowstoskip <= 0)
+ {
+ /*
+ * Found a suitable tuple, so save it,
replacing one
+ * old tuple at random
+ */
+ int k = (int) (targrows * random_fract());
+
+ Assert(k >= 0 && k < targrows);
+ heap_freetuple(rows[k]);
+
+ blknum = (BlockNumber) samplerows /
MaxOffsetNumber;
+ offnum = (OffsetNumber) samplerows %
MaxOffsetNumber + 1;
+ ItemPointerSet(&tuple->t_self, blknum, offnum);
+ rows[k] = heap_copytuple(tuple);
+ }
+
+ rowstoskip -= 1;
+ }
+
+ samplerows += 1;
+ heap_freetuple(tuple);
+ }
+
+ /*
+ * If we didn't find as many tuples as we wanted then we're done. No
sort
+ * is needed, since they're already in order.
+ *
+ * Otherwise we need to sort the collected tuples by position
+ * (itempointer). It's not worth worrying about corner cases where the
+ * tuples are already sorted.
+ */
+ if (numrows == targrows)
+ qsort((void *) rows, numrows, sizeof(HeapTuple), compare_rows);
+
+ *totalrows = samplerows;
+
+ EndCopyFrom(cstate);
+
+ pfree(values);
+ pfree(nulls);
+ pfree(force_notnull_flags);
+
+ /*
+ * Emit some interesting relation info
+ */
+ ereport(elevel,
+ (errmsg("\"%s\": scanned, "
+ "containing %d rows; "
+ "%d rows in sample",
+ RelationGetRelationName(onerel), (int)
samplerows, numrows)));
+
+ return numrows;
+ }
*** a/contrib/file_fdw/input/file_fdw.source
--- b/contrib/file_fdw/input/file_fdw.source
***************
*** 111,116 **** EXECUTE st(100);
--- 111,121 ----
EXECUTE st(100);
DEALLOCATE st;
+ -- statistics collection tests
+ ANALYZE agg_csv;
+ SELECT relpages, reltuples FROM pg_class WHERE relname = 'agg_csv';
+ SELECT * FROM pg_stats WHERE tablename = 'agg_csv';
+
-- tableoid
SELECT tableoid::regclass, b FROM agg_csv;
*** a/contrib/file_fdw/output/file_fdw.source
--- b/contrib/file_fdw/output/file_fdw.source
***************
*** 174,179 **** EXECUTE st(100);
--- 174,194 ----
(1 row)
DEALLOCATE st;
+ -- statistics collection tests
+ ANALYZE agg_csv;
+ SELECT relpages, reltuples FROM pg_class WHERE relname = 'agg_csv';
+ relpages | reltuples
+ ----------+-----------
+ 1 | 3
+ (1 row)
+
+ SELECT * FROM pg_stats WHERE tablename = 'agg_csv';
+ schemaname | tablename | attname | inherited | null_frac | avg_width |
n_distinct | most_common_vals | most_common_freqs | histogram_bounds |
correlation
+
------------+-----------+---------+-----------+-----------+-----------+------------+------------------+-------------------+-------------------------+-------------
+ public | agg_csv | a | f | 0 | 2 |
-1 | | | {0,42,100} |
-0.5
+ public | agg_csv | b | f | 0 | 4 |
-1 | | | {0.09561,99.097,324.78} |
0.5
+ (2 rows)
+
-- tableoid
SELECT tableoid::regclass, b FROM agg_csv;
tableoid | b
*** a/doc/src/sgml/fdwhandler.sgml
--- b/doc/src/sgml/fdwhandler.sgml
***************
*** 233,238 **** EndForeignScan (ForeignScanState *node);
--- 233,257 ----
for additional details.
</para>
+ <para>
+ <programlisting>
+ void
+ AnalyzeForeignTable (Relation onerel,
+ VacuumStmt *vacstmt,
+ int elevel);
+ </programlisting>
+
+ Collect statistics on a foreign table and store the results in the
+ pg_class and pg_statistics system catalog.
+ This is called when <command>ANALYZE</> command is run.
+ </para>
+
+ <para>
+ The <structname>FdwRoutine</> and <structname>FdwPlan</> struct types
+ are declared in <filename>src/include/foreign/fdwapi.h</>, which see
+ for additional details.
+ </para>
+
</sect1>
</chapter>
*** a/doc/src/sgml/ref/alter_foreign_table.sgml
--- b/doc/src/sgml/ref/alter_foreign_table.sgml
***************
*** 36,41 **** ALTER FOREIGN TABLE <replaceable
class="PARAMETER">name</replaceable>
--- 36,44 ----
DROP [ COLUMN ] [ IF EXISTS ] <replaceable
class="PARAMETER">column</replaceable> [ RESTRICT | CASCADE ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> [
SET DATA ] TYPE <replaceable class="PARAMETER">type</replaceable>
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> {
SET | DROP } NOT NULL
+ ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET
STATISTICS <replaceable class="PARAMETER">integer</replaceable>
+ ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET
( <replaceable class="PARAMETER">attribute_option</replaceable> = <replaceable
class="PARAMETER">value</replaceable> [, ... ] )
+ ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable>
RESET ( <replaceable class="PARAMETER">attribute_option</replaceable> [, ... ] )
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable>
OPTIONS ( [ ADD | SET | DROP ] <replaceable
class="PARAMETER">option</replaceable> ['<replaceable
class="PARAMETER">value</replaceable>'] [, ... ])
OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
OPTIONS ( [ ADD | SET | DROP ] <replaceable
class="PARAMETER">option</replaceable> ['<replaceable
class="PARAMETER">value</replaceable>'] [, ... ])
***************
*** 94,99 **** ALTER FOREIGN TABLE <replaceable
class="PARAMETER">name</replaceable>
--- 97,146 ----
</varlistentry>
<varlistentry>
+ <term><literal>SET STATISTICS</literal></term>
+ <listitem>
+ <para>
+ This form
+ sets the per-column statistics-gathering target for subsequent
+ <xref linkend="sql-analyze"> operations.
+ The target can be set in the range 0 to 10000; alternatively, set it
+ to -1 to revert to using the system default statistics
+ target (<xref linkend="guc-default-statistics-target">).
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>SET ( <replaceable
class="PARAMETER">attribute_option</replaceable> = <replaceable
class="PARAMETER">value</replaceable> [, ... ] )</literal></term>
+ <term><literal>RESET ( <replaceable
class="PARAMETER">attribute_option</replaceable> [, ... ] )</literal></term>
+ <listitem>
+ <para>
+ This form
+ sets or resets per-attribute options. Currently, the only defined
+ per-attribute options is <literal>n_distinct</>, which override
+ the number-of-distinct-values estimates made by subsequent
+ <xref linkend="sql-analyze"> operations. <literal>n_distinct</>
+ affects the statistics for the foreign table itself. When set to
+ a positive value, <command>ANALYZE</> will assume that the column
+ contains exactly the specified number of distinct nonnull values.
+ When set to a negative value, which must be greater than or equal
+ to -1, <command>ANALYZE</> will assume that the number of distinct
+ nonnull values in the column is linear in the size of the foreign
+ table; the exact count is to be computed by multiplying
+ the estimated foreign table size by the absolute value of
+ the given number. For example,
+ a value of -1 implies that all values in the column are distinct,
+ while a value of -0.5 implies that each value appears twice on the
+ average.
+ This can be useful when the size of the foreign table changes over
+ time, since the multiplication by the number of rows in the foreign
+ table is not performed until query planning time. Specify a value
+ of 0 to revert to estimating the number of distinct values normally.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><literal>OWNER</literal></term>
<listitem>
<para>
*** a/doc/src/sgml/ref/analyze.sgml
--- b/doc/src/sgml/ref/analyze.sgml
***************
*** 39,47 **** ANALYZE [ VERBOSE ] [ <replaceable
class="PARAMETER">table</replaceable> [ ( <re
<para>
With no parameter, <command>ANALYZE</command> examines every table in the
! current database. With a parameter, <command>ANALYZE</command> examines
! only that table. It is further possible to give a list of column names,
! in which case only the statistics for those columns are collected.
</para>
</refsect1>
--- 39,48 ----
<para>
With no parameter, <command>ANALYZE</command> examines every table in the
! current database except for foreign tables. With a parameter, <command>
! ANALYZE</command> examines only that table. It is further possible to
! give a list of column names, in which case only the statistics for those
! columns are collected.
</para>
</refsect1>
***************
*** 63,69 **** ANALYZE [ VERBOSE ] [ <replaceable
class="PARAMETER">table</replaceable> [ ( <re
<listitem>
<para>
The name (possibly schema-qualified) of a specific table to
! analyze. Defaults to all tables in the current database.
</para>
</listitem>
</varlistentry>
--- 64,71 ----
<listitem>
<para>
The name (possibly schema-qualified) of a specific table to
! analyze. Defaults to all tables in the current database except
! for foreign tables.
</para>
</listitem>
</varlistentry>
***************
*** 138,143 **** ANALYZE [ VERBOSE ] [ <replaceable
class="PARAMETER">table</replaceable> [ ( <re
--- 140,148 ----
choices of query plans to change after <command>ANALYZE</command> is run.
To avoid this, raise the amount of statistics collected by
<command>ANALYZE</command>, as described below.
+ Note that the time needed to analyze a foreign table depends on
+ the implementation of a foreign data wrappers via which that table is
+ attached.
</para>
<para>
*** a/src/backend/commands/analyze.c
--- b/src/backend/commands/analyze.c
***************
*** 22,27 ****
--- 22,28 ----
#include "access/xact.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
+ #include "catalog/pg_class.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_inherits_fn.h"
#include "catalog/pg_namespace.h"
***************
*** 29,34 ****
--- 30,37 ----
#include "commands/tablecmds.h"
#include "commands/vacuum.h"
#include "executor/executor.h"
+ #include "foreign/foreign.h"
+ #include "foreign/fdwapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "parser/parse_oper.h"
***************
*** 93,112 **** static void compute_index_stats(Relation onerel, double
totalrows,
AnlIndexData *indexdata, int nindexes,
HeapTuple *rows, int numrows,
MemoryContext col_context);
- static VacAttrStats *examine_attribute(Relation onerel, int attnum,
- Node *index_expr);
static int acquire_sample_rows(Relation onerel, HeapTuple *rows,
int targrows, double *totalrows, double
*totaldeadrows);
- static double random_fract(void);
- static double init_selection_state(int n);
- static double get_next_S(double t, int n, double *stateptr);
- static int compare_rows(const void *a, const void *b);
static int acquire_inherited_sample_rows(Relation onerel,
HeapTuple *rows, int
targrows,
double *totalrows,
double *totaldeadrows);
- static void update_attstats(Oid relid, bool inh,
- int natts, VacAttrStats **vacattrstats);
- static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
static Datum ind_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
static bool std_typanalyze(VacAttrStats *stats);
--- 96,106 ----
***************
*** 183,192 **** analyze_rel(Oid relid, VacuumStmt *vacstmt,
BufferAccessStrategy bstrategy)
}
/*
! * Check that it's a plain table; we used to do this in get_rel_oids()
but
! * seems safer to check after we've locked the relation.
*/
! if (onerel->rd_rel->relkind != RELKIND_RELATION)
{
/* No need for a WARNING if we already complained during VACUUM
*/
if (!(vacstmt->options & VACOPT_VACUUM))
--- 177,187 ----
}
/*
! * Check that it's a plain table or a foreign table; we used to do this
in
! * get_rel_oids() but seems safer to check after we've locked the
relation.
*/
! if (!(onerel->rd_rel->relkind == RELKIND_RELATION ||
! onerel->rd_rel->relkind == RELKIND_FOREIGN_TABLE))
{
/* No need for a WARNING if we already complained during VACUUM
*/
if (!(vacstmt->options & VACOPT_VACUUM))
***************
*** 228,240 **** analyze_rel(Oid relid, VacuumStmt *vacstmt,
BufferAccessStrategy bstrategy)
/*
* Do the normal non-recursive ANALYZE.
*/
! do_analyze_rel(onerel, vacstmt, false);
! /*
! * If there are child tables, do recursive ANALYZE.
! */
! if (onerel->rd_rel->relhassubclass)
! do_analyze_rel(onerel, vacstmt, true);
/*
* Close source relation now, but keep lock so that no one deletes it
--- 223,252 ----
/*
* Do the normal non-recursive ANALYZE.
*/
! if (onerel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
! {
! ForeignDataWrapper *wrapper;
! ForeignServer *server;
! ForeignTable *table;
! FdwRoutine *fdwroutine;
! table = GetForeignTable(RelationGetRelid(onerel));
! server = GetForeignServer(table->serverid);
! wrapper = GetForeignDataWrapper(server->fdwid);
! fdwroutine = GetFdwRoutine(wrapper->fdwhandler);
!
! fdwroutine->AnalyzeForeignTable(onerel, vacstmt, elevel);
! }
! else
! {
! do_analyze_rel(onerel, vacstmt, false);
!
! /*
! * If there are child tables, do recursive ANALYZE.
! */
! if (onerel->rd_rel->relhassubclass)
! do_analyze_rel(onerel, vacstmt, true);
! }
/*
* Close source relation now, but keep lock so that no one deletes it
***************
*** 342,348 **** do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, bool inh)
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation
\"%s\" does not exist",
col,
RelationGetRelationName(onerel))));
! vacattrstats[tcnt] = examine_attribute(onerel, i, NULL);
if (vacattrstats[tcnt] != NULL)
tcnt++;
}
--- 354,360 ----
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation
\"%s\" does not exist",
col,
RelationGetRelationName(onerel))));
! vacattrstats[tcnt] = examine_attribute(onerel, i, NULL,
anl_context);
if (vacattrstats[tcnt] != NULL)
tcnt++;
}
***************
*** 356,362 **** do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, bool inh)
tcnt = 0;
for (i = 1; i <= attr_cnt; i++)
{
! vacattrstats[tcnt] = examine_attribute(onerel, i, NULL);
if (vacattrstats[tcnt] != NULL)
tcnt++;
}
--- 368,374 ----
tcnt = 0;
for (i = 1; i <= attr_cnt; i++)
{
! vacattrstats[tcnt] = examine_attribute(onerel, i, NULL,
anl_context);
if (vacattrstats[tcnt] != NULL)
tcnt++;
}
***************
*** 410,416 **** do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, bool inh)
indexkey = (Node *)
lfirst(indexpr_item);
indexpr_item =
lnext(indexpr_item);
thisdata->vacattrstats[tcnt] =
!
examine_attribute(Irel[ind], i + 1, indexkey);
if
(thisdata->vacattrstats[tcnt] != NULL)
tcnt++;
}
--- 422,428 ----
indexkey = (Node *)
lfirst(indexpr_item);
indexpr_item =
lnext(indexpr_item);
thisdata->vacattrstats[tcnt] =
!
examine_attribute(Irel[ind], i + 1, indexkey, anl_context);
if
(thisdata->vacattrstats[tcnt] != NULL)
tcnt++;
}
***************
*** 800,807 **** compute_index_stats(Relation onerel, double totalrows,
* If index_expr isn't NULL, then we're trying to analyze an expression index,
* and index_expr is the expression tree representing the column's data.
*/
! static VacAttrStats *
! examine_attribute(Relation onerel, int attnum, Node *index_expr)
{
Form_pg_attribute attr = onerel->rd_att->attrs[attnum - 1];
HeapTuple typtuple;
--- 812,819 ----
* If index_expr isn't NULL, then we're trying to analyze an expression index,
* and index_expr is the expression tree representing the column's data.
*/
! VacAttrStats *
! examine_attribute(Relation onerel, int attnum, Node *index_expr,
MemoryContext anl_context)
{
Form_pg_attribute attr = onerel->rd_att->attrs[attnum - 1];
HeapTuple typtuple;
***************
*** 1247,1253 **** acquire_sample_rows(Relation onerel, HeapTuple *rows, int
targrows,
}
/* Select a random value R uniformly distributed in (0 - 1) */
! static double
random_fract(void)
{
return ((double) random() + 1) / ((double) MAX_RANDOM_VALUE + 2);
--- 1259,1265 ----
}
/* Select a random value R uniformly distributed in (0 - 1) */
! double
random_fract(void)
{
return ((double) random() + 1) / ((double) MAX_RANDOM_VALUE + 2);
***************
*** 1267,1280 **** random_fract(void)
* determines the number of records to skip before the next record is
* processed.
*/
! static double
init_selection_state(int n)
{
/* Initial value of W (for use when Algorithm Z is first applied) */
return exp(-log(random_fract()) / n);
}
! static double
get_next_S(double t, int n, double *stateptr)
{
double S;
--- 1279,1292 ----
* determines the number of records to skip before the next record is
* processed.
*/
! double
init_selection_state(int n)
{
/* Initial value of W (for use when Algorithm Z is first applied) */
return exp(-log(random_fract()) / n);
}
! double
get_next_S(double t, int n, double *stateptr)
{
double S;
***************
*** 1359,1365 **** get_next_S(double t, int n, double *stateptr)
/*
* qsort comparator for sorting rows[] array
*/
! static int
compare_rows(const void *a, const void *b)
{
HeapTuple ha = *(const HeapTuple *) a;
--- 1371,1377 ----
/*
* qsort comparator for sorting rows[] array
*/
! int
compare_rows(const void *a, const void *b)
{
HeapTuple ha = *(const HeapTuple *) a;
***************
*** 1554,1560 **** acquire_inherited_sample_rows(Relation onerel, HeapTuple
*rows, int targrows,
* ANALYZE the same table concurrently. Presently, we lock that
out
* by taking a self-exclusive lock on the relation in
analyze_rel().
*/
! static void
update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
{
Relation sd;
--- 1566,1572 ----
* ANALYZE the same table concurrently. Presently, we lock that
out
* by taking a self-exclusive lock on the relation in
analyze_rel().
*/
! void
update_attstats(Oid relid, bool inh, int natts, VacAttrStats **vacattrstats)
{
Relation sd;
***************
*** 1691,1697 **** update_attstats(Oid relid, bool inh, int natts, VacAttrStats
**vacattrstats)
* This exists to provide some insulation between compute_stats routines
* and the actual storage of the sample data.
*/
! static Datum
std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull)
{
int attnum = stats->tupattnum;
--- 1703,1709 ----
* This exists to provide some insulation between compute_stats routines
* and the actual storage of the sample data.
*/
! Datum
std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull)
{
int attnum = stats->tupattnum;
*** a/src/backend/commands/copy.c
--- b/src/backend/commands/copy.c
***************
*** 288,295 **** static Datum CopyReadBinaryAttribute(CopyState cstate,
static void CopyAttributeOutText(CopyState cstate, char *string);
static void CopyAttributeOutCSV(CopyState cstate, char *string,
bool use_quote, bool single_attr);
- static List *CopyGetAttnums(TupleDesc tupDesc, Relation rel,
- List *attnamelist);
static char *limit_printout_length(const char *str);
/* Low-level communications functions */
--- 288,293 ----
***************
*** 3725,3731 **** CopyAttributeOutCSV(CopyState cstate, char *string,
*
* rel can be NULL ... it's only used for error reports.
*/
! static List *
CopyGetAttnums(TupleDesc tupDesc, Relation rel, List *attnamelist)
{
List *attnums = NIL;
--- 3723,3729 ----
*
* rel can be NULL ... it's only used for error reports.
*/
! List *
CopyGetAttnums(TupleDesc tupDesc, Relation rel, List *attnamelist)
{
List *attnums = NIL;
*** a/src/backend/commands/tablecmds.c
--- b/src/backend/commands/tablecmds.c
***************
*** 311,316 **** static void ATPrepSetStatistics(Relation rel, const char
*colName,
--- 311,318 ----
Node *newValue, LOCKMODE lockmode);
static void ATExecSetStatistics(Relation rel, const char *colName,
Node *newValue, LOCKMODE lockmode);
+ static void ATPrepSetOptions(Relation rel, const char *colName,
+ Node *options, LOCKMODE lockmode);
static void ATExecSetOptions(Relation rel, const char *colName,
Node *options, bool isReset, LOCKMODE
lockmode);
static void ATExecSetStorage(Relation rel, const char *colName,
***************
*** 2886,2892 **** ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
break;
case AT_SetOptions: /* ALTER COLUMN SET ( options )
*/
case AT_ResetOptions: /* ALTER COLUMN RESET ( options ) */
! ATSimplePermissions(rel, ATT_TABLE | ATT_INDEX);
/* This command never recurses */
pass = AT_PASS_MISC;
break;
--- 2888,2895 ----
break;
case AT_SetOptions: /* ALTER COLUMN SET ( options )
*/
case AT_ResetOptions: /* ALTER COLUMN RESET ( options ) */
! ATSimplePermissions(rel, ATT_TABLE | ATT_INDEX |
ATT_FOREIGN_TABLE);
! ATPrepSetOptions(rel, cmd->name, cmd->def, lockmode);
/* This command never recurses */
pass = AT_PASS_MISC;
break;
***************
*** 4822,4828 **** ATPrepSetStatistics(Relation rel, const char *colName, Node
*newValue, LOCKMODE
* allowSystemTableMods to be turned on.
*/
if (rel->rd_rel->relkind != RELKIND_RELATION &&
! rel->rd_rel->relkind != RELKIND_INDEX)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or index",
--- 4825,4832 ----
* allowSystemTableMods to be turned on.
*/
if (rel->rd_rel->relkind != RELKIND_RELATION &&
! rel->rd_rel->relkind != RELKIND_INDEX &&
! rel->rd_rel->relkind != RELKIND_FOREIGN_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table or index",
***************
*** 4894,4899 **** ATExecSetStatistics(Relation rel, const char *colName, Node
*newValue, LOCKMODE
--- 4898,4923 ----
}
static void
+ ATPrepSetOptions(Relation rel, const char *colName, Node *options,
+ LOCKMODE lockmode)
+ {
+ if (rel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
+ {
+ ListCell *cell;
+
+ foreach(cell, (List *) options)
+ {
+ DefElem *def = (DefElem *) lfirst(cell);
+
+ if (pg_strncasecmp(def->defname,
"n_distinct_inherited", strlen("n_distinct_inherited")) == 0)
+ ereport(ERROR,
+
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("option
\"n_distinct_inherited\" is not supported for a foreign table")));
+ }
+ }
+ }
+
+ static void
ATExecSetOptions(Relation rel, const char *colName, Node *options,
bool isReset, LOCKMODE lockmode)
{
*** a/src/include/commands/copy.h
--- b/src/include/commands/copy.h
***************
*** 32,37 **** extern bool NextCopyFrom(CopyState cstate, ExprContext *econtext,
--- 32,38 ----
extern bool NextCopyFromRawFields(CopyState cstate,
char ***fields, int *nfields);
extern void CopyFromErrorCallback(void *arg);
+ extern List *CopyGetAttnums(TupleDesc tupDesc, Relation rel, List
*attnamelist);
extern DestReceiver *CreateCopyDestReceiver(void);
*** a/src/include/commands/vacuum.h
--- b/src/include/commands/vacuum.h
***************
*** 166,170 **** extern void lazy_vacuum_rel(Relation onerel, VacuumStmt
*vacstmt,
--- 166,178 ----
/* in commands/analyze.c */
extern void analyze_rel(Oid relid, VacuumStmt *vacstmt,
BufferAccessStrategy bstrategy);
+ extern VacAttrStats * examine_attribute(Relation onerel, int attnum, Node
*index_expr,
+ MemoryContext anl_context);
+ extern double random_fract(void);
+ extern double init_selection_state(int n);
+ extern double get_next_S(double t, int n, double *stateptr);
+ extern int compare_rows(const void *a, const void *b);
+ extern void update_attstats(Oid relid, bool inh, int natts, VacAttrStats
**vacattrstats);
+ extern Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
#endif /* VACUUM_H */
*** a/src/include/foreign/fdwapi.h
--- b/src/include/foreign/fdwapi.h
***************
*** 12,19 ****
--- 12,21 ----
#ifndef FDWAPI_H
#define FDWAPI_H
+ #include "foreign/foreign.h"
#include "nodes/execnodes.h"
#include "nodes/relation.h"
+ #include "utils/rel.h"
/* To avoid including explain.h here, reference ExplainState thus: */
struct ExplainState;
***************
*** 68,73 **** typedef void (*ReScanForeignScan_function) (ForeignScanState
*node);
--- 70,78 ----
typedef void (*EndForeignScan_function) (ForeignScanState *node);
+ typedef void (*AnalyzeForeignTable_function) (Relation relation,
+
VacuumStmt *vacstmt,
+
int elevel);
/*
* FdwRoutine is the struct returned by a foreign-data wrapper's handler
***************
*** 88,93 **** typedef struct FdwRoutine
--- 93,99 ----
IterateForeignScan_function IterateForeignScan;
ReScanForeignScan_function ReScanForeignScan;
EndForeignScan_function EndForeignScan;
+ AnalyzeForeignTable_function AnalyzeForeignTable;
} FdwRoutine;
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