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From: Shigeru Hanada <shigeru.hanada@gmail.com>
To: Etsuro Fujita <fujita.etsuro@lab.ntt.co.jp>
Cc: pgsql-hackers@postgresql.org
Subject: Re: WIP: Collecting statistics on CSV file data
Date: Wed, 14 Dec 2011 15:34:08 +0900
Message-ID: <4EE84360.90800@gmail.com> (raw)
In-Reply-To: <4EE74C5F.3000309@lab.ntt.co.jp>
References: <4E6DE18B.4010505@lab.ntt.co.jp>
	<4E7861C1.2000607@gmail.com>
	<4E8EC1D8.3080700@lab.ntt.co.jp>
	<4E9C6573.8050507@gmail.com>
	<4E9FF04B.3050504@lab.ntt.co.jp>
	<4EB7C07A.5030205@gmail.com>
	<4EC60883.2050905@lab.ntt.co.jp>
	<4EC648CA.5050904@gmail.com>
	<4EC9CBC5.3070500@lab.ntt.co.jp>
	<4EE1FC38.5080707@lab.ntt.co.jp>
	<4EE5D862.1080809@gmail.com>
	<4EE74C5F.3000309@lab.ntt.co.jp>

(2011/12/13 22:00), Etsuro Fujita wrote:
> Thank you for your effectiveness experiments and proposals for
> improvements.  I updated the patch according to your proposals.
> Attached is the updated version of the patch.

I think this patch could be marked as "Ready for committer" with some
minor fixes.  Please find attached a revised patch (v6.1).

Changes from Fujita-san's patch are:

* Fix a typo in src/backend/commands/analyze.c.
* Connect multi-lined message string literals, because PG code style
allows a line including message string literals to go past 80 columns.
* Fix ATPrepSetOptions so that it uses pg_strcasecmp instead of
pg_strncasecmp, becuase it's guaranteed that a) given strings are
null-terminated, and b) they have no trailing.

This feature would enhance cost estimation of foreign scans
substantially.  Great!

Regards,
-- 
Shigeru Hanada

  * $BITL@(B - $B<+F08!=P(B
  * $B1Q8l(B
  * $BF|K\8l(B

  * $B1Q8l(B
  * $BF|K\8l(B

 <javascript:void(0);>
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 1cf3b3c..4eb4e72 100644
*** a/contrib/file_fdw/file_fdw.c
--- b/contrib/file_fdw/file_fdw.c
***************
*** 20,25 ****
--- 20,26 ----
  #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"
*************** static void fileBeginForeignScan(Foreign
*** 101,106 ****
--- 102,110 ----
  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
*************** static List *get_file_fdw_attribute_opti
*** 112,118 ****
  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
--- 116,125 ----
  static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
  			   const char *filename,
  			   Cost *startup_cost, Cost *total_cost);
! static int	acquire_sample_rows(Relation onerel,
! 			   HeapTuple *rows, int targrows,
! 			   double *totalrows, double *totaldeadrows,
! 			   BlockNumber *totalpages, int elevel);
  
  /*
   * Foreign-data wrapper handler function: return a struct with pointers
*************** file_fdw_handler(PG_FUNCTION_ARGS)
*** 129,134 ****
--- 136,142 ----
  	fdwroutine->IterateForeignScan = fileIterateForeignScan;
  	fdwroutine->ReScanForeignScan = fileReScanForeignScan;
  	fdwroutine->EndForeignScan = fileEndForeignScan;
+ 	fdwroutine->AnalyzeForeignTable = fileAnalyzeForeignTable;
  
  	PG_RETURN_POINTER(fdwroutine);
  }
*************** fileReScanForeignScan(ForeignScanState *
*** 575,580 ****
--- 583,600 ----
  }
  
  /*
+  * fileAnalyzeForeignTable
+  *		Analyze foreign table
+  */
+ static void
+ fileAnalyzeForeignTable(Relation onerel, VacuumStmt *vacstmt, int elevel)
+ {
+ 	do_analyze_rel(onerel, vacstmt,
+ 				   elevel, false,
+ 				   acquire_sample_rows);
+ }
+ 
+ /*
   * Estimate costs of scanning a foreign table.
   */
  static void
*************** estimate_costs(PlannerInfo *root, RelOpt
*** 584,590 ****
  {
  	struct stat stat_buf;
  	BlockNumber pages;
! 	int			tuple_width;
  	double		ntuples;
  	double		nrows;
  	Cost		run_cost = 0;
--- 604,611 ----
  {
  	struct stat stat_buf;
  	BlockNumber pages;
! 	BlockNumber	relpages;
! 	double		reltuples;
  	double		ntuples;
  	double		nrows;
  	Cost		run_cost = 0;
*************** estimate_costs(PlannerInfo *root, RelOpt
*** 604,619 ****
  	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
--- 625,658 ----
  	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
*************** estimate_costs(PlannerInfo *root, RelOpt
*** 645,647 ****
--- 684,872 ----
  	run_cost += cpu_per_tuple * ntuples;
  	*total_cost = *startup_cost + run_cost;
  }
+ 
+ /*
+  * 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 valid 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
+ acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
+ 					double *totalrows, double *totaldeadrows,
+ 					BlockNumber *totalpages, int elevel)
+ {
+ 	int			numrows = 0;
+ 	int			invalrows = 0; /* total # rows violating
+ 								  the NOT NULL constraints */
+ 	double		validrows = 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;
+ 	char	   *filename;
+ 	struct stat	stat_buf;
+ 	List	   *options;
+ 	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));
+ 
+ 	/* Fetch options of foreign table */
+ 	fileGetOptions(RelationGetRelid(onerel), &filename, &options);
+ 
+ 	/*
+ 	 * 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);
+ 
+ 	/* Set up callback to identify error line number. */
+ 	errcontext.callback = CopyFromErrorCallback;
+ 	errcontext.arg = (void *) cstate;
+ 	errcontext.previous = error_context_stack;
+ 	error_context_stack = &errcontext;
+ 
+ 	for (;;)
+ 	{
+ 		sample_it = true;
+ 
+ 		/*
+ 		 * Check for user-requested abort.
+ 		 */
+ 		CHECK_FOR_INTERRUPTS();
+ 
+ 		found = NextCopyFrom(cstate, NULL, values, nulls, NULL);
+ 
+ 		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 &&
+ 					heap_attisnull(tuple, attrChk))
+ 				{
+ 					sample_it = false;
+ 					break;
+ 				}
+ 			}
+ 		}
+ 
+ 		if (!sample_it)
+ 		{
+ 			invalrows += 1;
+ 			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)
+ 			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(validrows, 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]);
+ 				rows[k] = heap_copytuple(tuple);
+ 			}
+ 
+ 			rowstoskip -= 1;
+ 		}
+ 
+ 		validrows += 1;
+ 		heap_freetuple(tuple);
+ 	}
+ 
+ 	/* Remove error callback. */
+ 	error_context_stack = errcontext.previous;
+ 
+ 	*totalrows = validrows;
+ 	*totaldeadrows = 0;
+ 
+ 	EndCopyFrom(cstate);
+ 
+ 	pfree(values);
+ 	pfree(nulls);
+ 
+ 	/*
+ 	 * Emit some interesting relation info
+ 	 */
+ 	ereport(elevel,
+ 			(errmsg("\"%s\": scanned, "
+ 					"containing %d valid rows and %d invalid rows; "
+ 					"%d rows in sample, %d total rows",
+ 					RelationGetRelationName(onerel),
+ 					(int) validrows, invalrows,
+ 					numrows, (int) *totalrows)));
+ 
+ 	return numrows;
+ }
diff --git a/contrib/file_fdw/input/file_fdw.source b/contrib/file_fdw/input/file_fdw.source
index 8e3d553..21b6fb4 100644
*** a/contrib/file_fdw/input/file_fdw.source
--- b/contrib/file_fdw/input/file_fdw.source
*************** EXECUTE st(100);
*** 111,116 ****
--- 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;
  
diff --git a/contrib/file_fdw/output/file_fdw.source b/contrib/file_fdw/output/file_fdw.source
index 84f0750..fe0d67f 100644
*** a/contrib/file_fdw/output/file_fdw.source
--- b/contrib/file_fdw/output/file_fdw.source
*************** EXECUTE st(100);
*** 174,179 ****
--- 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    
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index 76ff243..7d6443a 100644
*** a/doc/src/sgml/fdwhandler.sgml
--- b/doc/src/sgml/fdwhandler.sgml
*************** EndForeignScan (ForeignScanState *node);
*** 228,233 ****
--- 228,257 ----
      </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 catalogs.
+      This is optional, and if implemented, called when <command>ANALYZE
+      </> command is run.
+      The statistics are used by the query planner in order to make good
+      choices of query plans.
+      The function can be implemented by writing a sampling function that
+      acquires a random sample of rows from an external data source and
+      then by calling <function>do_analyze_rel</>, where you should pass
+      the sampling function as an argument.
+      Or the function can be directly implemented to get the statistics
+      from an external data source, transform it if neccesary, and store
+      it in the pg_class and pg_statistics system catalogs.
+      The function must be set to NULL if it isn't implemented.
+     </para>
+ 
+     <para>
       The <structname>FdwRoutine</> and <structname>FdwPlan</> struct types
       are declared in <filename>src/include/foreign/fdwapi.h</>, which see
       for additional details.
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 03cc6c9..82795d1 100644
*** a/doc/src/sgml/maintenance.sgml
--- b/doc/src/sgml/maintenance.sgml
***************
*** 279,284 ****
--- 279,288 ----
      <command>ANALYZE</> strictly as a function of the number of rows
      inserted or updated; it has no knowledge of whether that will lead
      to meaningful statistical changes.
+     Note that the autovacuum daemon does not issue <command>ANALYZE</>
+     commands on foreign tables.  It is recommended to run manually-managed
+     <command>ANALYZE</> commands as needed, which typically are executed
+     according to a schedule by cron or Task Scheduler scripts.
     </para>
  
     <para>
diff --git a/doc/src/sgml/ref/alter_foreign_table.sgml b/doc/src/sgml/ref/alter_foreign_table.sgml
index 5c7a86f..9fbb108 100644
*** a/doc/src/sgml/ref/alter_foreign_table.sgml
--- b/doc/src/sgml/ref/alter_foreign_table.sgml
*************** ALTER FOREIGN TABLE <replaceable class="
*** 36,41 ****
--- 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>'] [, ... ])
*************** ALTER FOREIGN TABLE <replaceable class="
*** 94,99 ****
--- 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 a per-attribute option.  Currently, the only defined
+       per-attribute option is <literal>n_distinct</>, which overrides
+       the number-of-distinct-values estimates made by subsequent
+       <xref linkend="sql-analyze"> operations. 
+       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>
diff --git a/doc/src/sgml/ref/analyze.sgml b/doc/src/sgml/ref/analyze.sgml
index 7545fa5..fe13b2b 100644
*** a/doc/src/sgml/ref/analyze.sgml
--- b/doc/src/sgml/ref/analyze.sgml
*************** ANALYZE [ VERBOSE ] [ <replaceable class
*** 39,47 ****
  
    <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>
  
--- 39,49 ----
  
    <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.  For a foreign table, it is
!    necessary to specify the name of 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>
  
*************** ANALYZE [ VERBOSE ] [ <replaceable class
*** 63,69 ****
      <listitem>
       <para>
        The name (possibly schema-qualified) of a specific table to
!       analyze. Defaults to all tables in the current database.
       </para>
      </listitem>
     </varlistentry>
--- 65,72 ----
      <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>
*************** ANALYZE [ VERBOSE ] [ <replaceable class
*** 137,143 ****
     In rare situations, this non-determinism will cause the planner's
     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.
    </para>
  
    <para>
--- 140,148 ----
     In rare situations, this non-determinism will cause the planner's
     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 on foreign tables depends on the implementation of
!    the foreign data wrapper via which such tables are attached.
    </para>
  
    <para>
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index c3d3958..fa5fa7e 100644
*** a/src/backend/commands/analyze.c
--- b/src/backend/commands/analyze.c
***************
*** 23,28 ****
--- 23,29 ----
  #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"
***************
*** 30,35 ****
--- 31,38 ----
  #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"
*************** typedef struct AnlIndexData
*** 78,91 ****
  int			default_statistics_target = 100;
  
  /* A few variables that don't seem worth passing around as parameters */
- static int	elevel = -1;
- 
  static MemoryContext anl_context = NULL;
  
  static BufferAccessStrategy vac_strategy;
  
  
- static void do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, bool inh);
  static void BlockSampler_Init(BlockSampler bs, BlockNumber nblocks,
  				  int samplesize);
  static bool BlockSampler_HasMore(BlockSampler bs);
--- 81,91 ----
*************** static void compute_index_stats(Relation
*** 96,110 ****
  					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);
--- 96,110 ----
  					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,
! 							   BlockNumber *totalpages, int elevel);
  static int acquire_inherited_sample_rows(Relation onerel,
  							  HeapTuple *rows, int targrows,
! 							  double *totalrows, double *totaldeadrows,
! 							  BlockNumber *totalpages, int elevel);
! static int	compare_rows(const void *a, const void *b);
  static void update_attstats(Oid relid, bool inh,
  				int natts, VacAttrStats **vacattrstats);
  static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
*************** static bool std_typanalyze(VacAttrStats 
*** 119,125 ****
--- 119,127 ----
  void
  analyze_rel(Oid relid, VacuumStmt *vacstmt, BufferAccessStrategy bstrategy)
  {
+ 	int			elevel;
  	Relation	onerel;
+ 	FdwRoutine *fdwroutine;
  
  	/* Set up static variables */
  	if (vacstmt->options & VACOPT_VERBOSE)
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 184,193 ****
  	}
  
  	/*
! 	 * 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))
--- 186,197 ----
  	}
  
  	/*
! 	 * Check that it's a plain table or 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))
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 211,217 ****
  	}
  
  	/*
! 	 * We can ANALYZE any table except pg_statistic. See update_attstats
  	 */
  	if (RelationGetRelid(onerel) == StatisticRelationId)
  	{
--- 215,223 ----
  	}
  
  	/*
! 	 * We can ANALYZE any table except pg_statistic.  See update_attstats.  In
! 	 * addition, we can ANALYZE foreign tables if AnalyzeForeignTable callback
! 	 * routines of underlying foreign-data wrappers are implemented.
  	 */
  	if (RelationGetRelid(onerel) == StatisticRelationId)
  	{
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 219,224 ****
--- 225,244 ----
  		return;
  	}
  
+ 	if (onerel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
+ 	{
+  		fdwroutine = GetFdwRoutineByRelId(RelationGetRelid(onerel));
+ 
+ 		if (fdwroutine->AnalyzeForeignTable == NULL)
+ 		{
+ 			ereport(WARNING,
+ 					(errmsg("skipping \"%s\" --- underlying foreign-data wrapper cannot analyze it",
+ 							RelationGetRelationName(onerel))));
+ 			relation_close(onerel, ShareUpdateExclusiveLock);
+ 			return;
+ 		}
+ 	}
+ 
  	/*
  	 * OK, let's do it.  First let other backends know I'm in ANALYZE.
  	 */
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 226,241 ****
  	MyPgXact->vacuumFlags |= PROC_IN_ANALYZE;
  	LWLockRelease(ProcArrayLock);
  
! 	/*
! 	 * 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
--- 246,283 ----
  	MyPgXact->vacuumFlags |= PROC_IN_ANALYZE;
  	LWLockRelease(ProcArrayLock);
  
! 	if (onerel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
! 	{
! 		ereport(elevel,
! 				(errmsg("analyzing \"%s.%s\"",
! 						get_namespace_name(RelationGetNamespace(onerel)),
! 						RelationGetRelationName(onerel))));
! 		fdwroutine->AnalyzeForeignTable(onerel, vacstmt, elevel);
! 	}
! 	else
! 	{
! 		/*
! 		 * Do the normal non-recursive ANALYZE.
! 		 */
! 		ereport(elevel,
! 				(errmsg("analyzing \"%s.%s\"",
! 						get_namespace_name(RelationGetNamespace(onerel)),
! 						RelationGetRelationName(onerel))));
! 		do_analyze_rel(onerel, vacstmt, elevel, false, acquire_sample_rows);
  
! 		/*
! 		 * If there are child tables, do recursive ANALYZE.
! 		 */
! 		if (onerel->rd_rel->relhassubclass)
! 		{
! 			ereport(elevel,
! 					(errmsg("analyzing \"%s.%s\" inheritance tree",
! 							get_namespace_name(RelationGetNamespace(onerel)),
! 							RelationGetRelationName(onerel))));
! 			do_analyze_rel(onerel, vacstmt, elevel, true,
! 						   acquire_inherited_sample_rows);
! 		}
! 	}
  
  	/*
  	 * Close source relation now, but keep lock so that no one deletes it
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 257,264 ****
  /*
   *	do_analyze_rel() -- analyze one relation, recursively or not
   */
! static void
! do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, bool inh)
  {
  	int			attr_cnt,
  				tcnt,
--- 299,307 ----
  /*
   *	do_analyze_rel() -- analyze one relation, recursively or not
   */
! void
! do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, int elevel, 
! 			   bool inh, SampleRowAcquireFunc acquirefunc)
  {
  	int			attr_cnt,
  				tcnt,
*************** do_analyze_rel(Relation onerel, VacuumSt
*** 273,278 ****
--- 316,322 ----
  				numrows;
  	double		totalrows,
  				totaldeadrows;
+ 	BlockNumber totalpages;
  	HeapTuple  *rows;
  	PGRUsage	ru0;
  	TimestampTz starttime = 0;
*************** do_analyze_rel(Relation onerel, VacuumSt
*** 281,297 ****
  	int			save_sec_context;
  	int			save_nestlevel;
  
- 	if (inh)
- 		ereport(elevel,
- 				(errmsg("analyzing \"%s.%s\" inheritance tree",
- 						get_namespace_name(RelationGetNamespace(onerel)),
- 						RelationGetRelationName(onerel))));
- 	else
- 		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.
--- 325,330 ----
*************** do_analyze_rel(Relation onerel, VacuumSt
*** 449,459 ****
  	 */
  	rows = (HeapTuple *) palloc(targrows * sizeof(HeapTuple));
  	if (inh)
! 		numrows = acquire_inherited_sample_rows(onerel, rows, targrows,
! 												&totalrows, &totaldeadrows);
  	else
! 		numrows = acquire_sample_rows(onerel, rows, targrows,
! 									  &totalrows, &totaldeadrows);
  
  	/*
  	 * Compute the statistics.	Temporary results during the calculations for
--- 482,494 ----
  	 */
  	rows = (HeapTuple *) palloc(targrows * sizeof(HeapTuple));
  	if (inh)
! 		numrows = acquirefunc(onerel, rows, targrows,
! 							  &totalrows, &totaldeadrows,
! 							  NULL, elevel);
  	else
! 		numrows = acquirefunc(onerel, rows, targrows,
! 							  &totalrows, &totaldeadrows,
! 							  &totalpages, elevel);
  
  	/*
  	 * Compute the statistics.	Temporary results during the calculations for
*************** do_analyze_rel(Relation onerel, VacuumSt
*** 534,540 ****
  	 */
  	if (!inh)
  		vac_update_relstats(onerel,
! 							RelationGetNumberOfBlocks(onerel),
  							totalrows,
  							visibilitymap_count(onerel),
  							hasindex,
--- 569,575 ----
  	 */
  	if (!inh)
  		vac_update_relstats(onerel,
! 							totalpages,
  							totalrows,
  							visibilitymap_count(onerel),
  							hasindex,
*************** BlockSampler_Next(BlockSampler bs)
*** 1017,1023 ****
   */
  static int
  acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
! 					double *totalrows, double *totaldeadrows)
  {
  	int			numrows = 0;	/* # rows now in reservoir */
  	double		samplerows = 0; /* total # rows collected */
--- 1052,1059 ----
   */
  static int
  acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
! 					double *totalrows, double *totaldeadrows,
! 					BlockNumber *totalpages, int elevel)
  {
  	int			numrows = 0;	/* # rows now in reservoir */
  	double		samplerows = 0; /* total # rows collected */
*************** acquire_sample_rows(Relation onerel, Hea
*** 1032,1037 ****
--- 1068,1075 ----
  	Assert(targrows > 0);
  
  	totalblocks = RelationGetNumberOfBlocks(onerel);
+ 	if (totalpages)
+ 		*totalpages = totalblocks;
  
  	/* Need a cutoff xmin for HeapTupleSatisfiesVacuum */
  	OldestXmin = GetOldestXmin(onerel->rd_rel->relisshared, true);
*************** acquire_sample_rows(Relation onerel, Hea
*** 1254,1260 ****
  }
  
  /* Select a random value R uniformly distributed in (0 - 1) */
! static double
  random_fract(void)
  {
  	return ((double) random() + 1) / ((double) MAX_RANDOM_VALUE + 2);
--- 1292,1298 ----
  }
  
  /* Select a random value R uniformly distributed in (0 - 1) */
! double
  random_fract(void)
  {
  	return ((double) random() + 1) / ((double) MAX_RANDOM_VALUE + 2);
*************** random_fract(void)
*** 1274,1287 ****
   * 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;
--- 1312,1325 ----
   * 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;
*************** compare_rows(const void *a, const void *
*** 1397,1403 ****
   */
  static int
  acquire_inherited_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
! 							  double *totalrows, double *totaldeadrows)
  {
  	List	   *tableOIDs;
  	Relation   *rels;
--- 1435,1442 ----
   */
  static int
  acquire_inherited_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
! 							  double *totalrows, double *totaldeadrows,
! 							  BlockNumber *totalpages, int elevel)
  {
  	List	   *tableOIDs;
  	Relation   *rels;
*************** acquire_inherited_sample_rows(Relation o
*** 1460,1465 ****
--- 1499,1506 ----
  		totalblocks += relblocks[nrels];
  		nrels++;
  	}
+ 	if (totalpages)
+ 	  *totalpages = totalblocks;
  
  	/*
  	 * Now sample rows from each relation, proportionally to its fraction of
*************** acquire_inherited_sample_rows(Relation o
*** 1493,1499 ****
  												rows + numrows,
  												childtargrows,
  												&trows,
! 												&tdrows);
  
  				/* We may need to convert from child's rowtype to parent's */
  				if (childrows > 0 &&
--- 1534,1542 ----
  												rows + numrows,
  												childtargrows,
  												&trows,
! 												&tdrows,
! 												NULL,
! 												elevel);
  
  				/* We may need to convert from child's rowtype to parent's */
  				if (childrows > 0 &&
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1ee201c..9e7c063 100644
*** a/src/backend/commands/tablecmds.c
--- b/src/backend/commands/tablecmds.c
*************** static void ATPrepSetStatistics(Relation
*** 317,322 ****
--- 317,324 ----
  					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,
*************** ATPrepCmd(List **wqueue, Relation rel, A
*** 2915,2921 ****
  			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;
--- 2917,2924 ----
  			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;
*************** ATPrepSetStatistics(Relation rel, const 
*** 4851,4860 ****
  	 * 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",
  						RelationGetRelationName(rel))));
  
  	/* Permissions checks */
--- 4854,4864 ----
  	 * 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, index or foreign table",
  						RelationGetRelationName(rel))));
  
  	/* Permissions checks */
*************** ATExecSetStatistics(Relation rel, const 
*** 4923,4928 ****
--- 4927,4952 ----
  }
  
  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_strcasecmp(def->defname, "n_distinct_inherited") == 0)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ 						 errmsg("cannot set \"n_distinct_inherited\" for foreign tables")));
+ 		}
+ 	}
+ }
+ 
+ static void
  ATExecSetOptions(Relation rel, const char *colName, Node *options,
  				 bool isReset, LOCKMODE lockmode)
  {
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index dcafdd2..802abf2 100644
*** a/src/bin/psql/describe.c
--- b/src/bin/psql/describe.c
*************** describeOneTableDetails(const char *sche
*** 1099,1105 ****
  	bool		printTableInitialized = false;
  	int			i;
  	char	   *view_def = NULL;
! 	char	   *headers[6];
  	char	  **seq_values = NULL;
  	char	  **modifiers = NULL;
  	char	  **ptr;
--- 1099,1105 ----
  	bool		printTableInitialized = false;
  	int			i;
  	char	   *view_def = NULL;
! 	char	   *headers[7];
  	char	  **seq_values = NULL;
  	char	  **modifiers = NULL;
  	char	  **ptr;
*************** describeOneTableDetails(const char *sche
*** 1390,1396 ****
  	if (verbose)
  	{
  		headers[cols++] = gettext_noop("Storage");
! 		if (tableinfo.relkind == 'r')
  			headers[cols++] = gettext_noop("Stats target");
  		/* Column comments, if the relkind supports this feature. */
  		if (tableinfo.relkind == 'r' || tableinfo.relkind == 'v' ||
--- 1390,1396 ----
  	if (verbose)
  	{
  		headers[cols++] = gettext_noop("Storage");
! 		if (tableinfo.relkind == 'r' || tableinfo.relkind == 'f')
  			headers[cols++] = gettext_noop("Stats target");
  		/* Column comments, if the relkind supports this feature. */
  		if (tableinfo.relkind == 'r' || tableinfo.relkind == 'v' ||
*************** describeOneTableDetails(const char *sche
*** 1493,1499 ****
  							  false, false);
  
  			/* Statistics target, if the relkind supports this feature */
! 			if (tableinfo.relkind == 'r')
  			{
  				printTableAddCell(&cont, PQgetvalue(res, i, firstvcol + 1),
  								  false, false);
--- 1493,1499 ----
  							  false, false);
  
  			/* Statistics target, if the relkind supports this feature */
! 			if (tableinfo.relkind == 'r' || tableinfo.relkind == 'f')
  			{
  				printTableAddCell(&cont, PQgetvalue(res, i, firstvcol + 1),
  								  false, false);
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index bb0fa09..1507a61 100644
*** a/src/bin/psql/tab-complete.c
--- b/src/bin/psql/tab-complete.c
*************** static const SchemaQuery Query_for_list_
*** 399,404 ****
--- 399,419 ----
  	NULL
  };
  
+ static const SchemaQuery Query_for_list_of_tf = {
+ 	/* catname */
+ 	"pg_catalog.pg_class c",
+ 	/* selcondition */
+ 	"c.relkind IN ('r', 'f')",
+ 	/* viscondition */
+ 	"pg_catalog.pg_table_is_visible(c.oid)",
+ 	/* namespace */
+ 	"c.relnamespace",
+ 	/* result */
+ 	"pg_catalog.quote_ident(c.relname)",
+ 	/* qualresult */
+ 	NULL
+ };
+ 
  static const SchemaQuery Query_for_list_of_views = {
  	/* catname */
  	"pg_catalog.pg_class c",
*************** psql_completion(char *text, int start, i
*** 2769,2775 ****
  /* ANALYZE */
  	/* If the previous word is ANALYZE, produce list of tables */
  	else if (pg_strcasecmp(prev_wd, "ANALYZE") == 0)
! 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_tables, NULL);
  
  /* WHERE */
  	/* Simple case of the word before the where being the table name */
--- 2784,2790 ----
  /* ANALYZE */
  	/* If the previous word is ANALYZE, produce list of tables */
  	else if (pg_strcasecmp(prev_wd, "ANALYZE") == 0)
! 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_tf, NULL);
  
  /* WHERE */
  	/* Simple case of the word before the where being the table name */
diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h
index d8fd0ca..0c24e2d 100644
*** a/src/include/commands/vacuum.h
--- b/src/include/commands/vacuum.h
*************** extern void lazy_vacuum_rel(Relation one
*** 165,171 ****
--- 165,182 ----
  				BufferAccessStrategy bstrategy);
  
  /* in commands/analyze.c */
+ typedef int (*SampleRowAcquireFunc) (Relation onerel, HeapTuple *rows,
+ 									 int targrows,
+ 									 double *totalrows, double *totaldeadrows,
+ 									 BlockNumber *totalpages, int elevel);
+ 
  extern void analyze_rel(Oid relid, VacuumStmt *vacstmt,
  			BufferAccessStrategy bstrategy);
+ extern void do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, int elevel, 
+ 						   bool inh, SampleRowAcquireFunc acquirefunc);
+ extern double random_fract(void);
+ extern double init_selection_state(int n);
+ extern double get_next_S(double t, int n, double *stateptr);
+ 
  
  #endif   /* VACUUM_H */
diff --git a/src/include/foreign/fdwapi.h b/src/include/foreign/fdwapi.h
index 3378ba9..3543f15 100644
*** 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;
*************** typedef void (*ReScanForeignScan_functio
*** 68,73 ****
--- 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
*************** typedef struct FdwRoutine
*** 82,93 ****
--- 87,109 ----
  {
  	NodeTag		type;
  
+ 	/*
+ 	 * These handlers are required to execute simple scans on a foreign
+ 	 * table.  If any of them was set to NULL, scans on a foreign table
+ 	 * managed by FDW would fail.
+ 	 */
  	PlanForeignScan_function PlanForeignScan;
  	ExplainForeignScan_function ExplainForeignScan;
  	BeginForeignScan_function BeginForeignScan;
  	IterateForeignScan_function IterateForeignScan;
  	ReScanForeignScan_function ReScanForeignScan;
  	EndForeignScan_function EndForeignScan;
+ 
+ 	/*
+ 	 * Handlers below are optional.  You can set any of them to NULL to
+ 	 * tell PostgreSQL that FDW doesn't have the capability.
+ 	 */
+ 	AnalyzeForeignTable_function AnalyzeForeignTable;
  } FdwRoutine;
  
  
diff --git a/src/test/regress/expected/foreign_data.out b/src/test/regress/expected/foreign_data.out
index 122e285..48a07f3 100644
*** a/src/test/regress/expected/foreign_data.out
--- b/src/test/regress/expected/foreign_data.out
*************** CREATE FOREIGN TABLE ft1 (
*** 678,689 ****
  COMMENT ON FOREIGN TABLE ft1 IS 'ft1';
  COMMENT ON COLUMN ft1.c1 IS 'ft1.c1';
  \d+ ft1
!                                Foreign table "public.ft1"
!  Column |  Type   | Modifiers |          FDW Options           | Storage  | Description 
! --------+---------+-----------+--------------------------------+----------+-------------
!  c1     | integer | not null  | ("param 1" 'val1')             | plain    | ft1.c1
!  c2     | text    |           | (param2 'val2', param3 'val3') | extended | 
!  c3     | date    |           |                                | plain    | 
  Server: s0
  FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
  Has OIDs: no
--- 678,689 ----
  COMMENT ON FOREIGN TABLE ft1 IS 'ft1';
  COMMENT ON COLUMN ft1.c1 IS 'ft1.c1';
  \d+ ft1
!                                       Foreign table "public.ft1"
!  Column |  Type   | Modifiers |          FDW Options           | Storage  | Stats target | Description 
! --------+---------+-----------+--------------------------------+----------+--------------+-------------
!  c1     | integer | not null  | ("param 1" 'val1')             | plain    |              | ft1.c1
!  c2     | text    |           | (param2 'val2', param3 'val3') | extended |              | 
!  c3     | date    |           |                                | plain    |              | 
  Server: s0
  FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
  Has OIDs: no
*************** ERROR:  cannot alter system column "xmin
*** 729,747 ****
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c7 OPTIONS (ADD p1 'v1', ADD p2 'v2'),
                          ALTER COLUMN c8 OPTIONS (ADD p1 'v1', ADD p2 'v2');
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 OPTIONS (SET p2 'V2', DROP p1);
  \d+ ft1
!                                Foreign table "public.ft1"
!  Column |  Type   | Modifiers |          FDW Options           | Storage  | Description 
! --------+---------+-----------+--------------------------------+----------+-------------
!  c1     | integer | not null  | ("param 1" 'val1')             | plain    | 
!  c2     | text    |           | (param2 'val2', param3 'val3') | extended | 
!  c3     | date    |           |                                | plain    | 
!  c4     | integer |           |                                | plain    | 
!  c6     | integer | not null  |                                | plain    | 
!  c7     | integer |           | (p1 'v1', p2 'v2')             | plain    | 
!  c8     | text    |           | (p2 'V2')                      | extended | 
!  c9     | integer |           |                                | plain    | 
!  c10    | integer |           | (p1 'v1')                      | plain    | 
  Server: s0
  FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
  Has OIDs: no
--- 729,752 ----
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c7 OPTIONS (ADD p1 'v1', ADD p2 'v2'),
                          ALTER COLUMN c8 OPTIONS (ADD p1 'v1', ADD p2 'v2');
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 OPTIONS (SET p2 'V2', DROP p1);
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET STATISTICS 10000;
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct = 100);
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct_inherited = 100); -- ERROR
+ ERROR:  cannot set "n_distinct_inherited" for foreign tables
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STATISTICS -1;
  \d+ ft1
!                                       Foreign table "public.ft1"
!  Column |  Type   | Modifiers |          FDW Options           | Storage  | Stats target | Description 
! --------+---------+-----------+--------------------------------+----------+--------------+-------------
!  c1     | integer | not null  | ("param 1" 'val1')             | plain    | 10000        | 
!  c2     | text    |           | (param2 'val2', param3 'val3') | extended |              | 
!  c3     | date    |           |                                | plain    |              | 
!  c4     | integer |           |                                | plain    |              | 
!  c6     | integer | not null  |                                | plain    |              | 
!  c7     | integer |           | (p1 'v1', p2 'v2')             | plain    |              | 
!  c8     | text    |           | (p2 'V2')                      | extended |              | 
!  c9     | integer |           |                                | plain    |              | 
!  c10    | integer |           | (p1 'v1')                      | plain    |              | 
  Server: s0
  FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
  Has OIDs: no
diff --git a/src/test/regress/sql/foreign_data.sql b/src/test/regress/sql/foreign_data.sql
index e99e707..5908ff3 100644
*** a/src/test/regress/sql/foreign_data.sql
--- b/src/test/regress/sql/foreign_data.sql
*************** ALTER FOREIGN TABLE ft1 ALTER COLUMN xmi
*** 306,311 ****
--- 306,315 ----
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c7 OPTIONS (ADD p1 'v1', ADD p2 'v2'),
                          ALTER COLUMN c8 OPTIONS (ADD p1 'v1', ADD p2 'v2');
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 OPTIONS (SET p2 'V2', DROP p1);
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET STATISTICS 10000;
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct = 100);
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct_inherited = 100); -- ERROR
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STATISTICS -1;
  \d+ ft1
  -- can't change the column type if it's used elsewhere
  CREATE TABLE use_ft1_column_type (x ft1);


Attachments:

  [text/plain] postgresql-analyze-v6.1.patch (47.1K, ../4EE84360.90800@gmail.com/2-postgresql-analyze-v6.1.patch)
  download | inline diff:
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 1cf3b3c..4eb4e72 100644
*** a/contrib/file_fdw/file_fdw.c
--- b/contrib/file_fdw/file_fdw.c
***************
*** 20,25 ****
--- 20,26 ----
  #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"
*************** static void fileBeginForeignScan(Foreign
*** 101,106 ****
--- 102,110 ----
  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
*************** static List *get_file_fdw_attribute_opti
*** 112,118 ****
  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
--- 116,125 ----
  static void estimate_costs(PlannerInfo *root, RelOptInfo *baserel,
  			   const char *filename,
  			   Cost *startup_cost, Cost *total_cost);
! static int	acquire_sample_rows(Relation onerel,
! 			   HeapTuple *rows, int targrows,
! 			   double *totalrows, double *totaldeadrows,
! 			   BlockNumber *totalpages, int elevel);
  
  /*
   * Foreign-data wrapper handler function: return a struct with pointers
*************** file_fdw_handler(PG_FUNCTION_ARGS)
*** 129,134 ****
--- 136,142 ----
  	fdwroutine->IterateForeignScan = fileIterateForeignScan;
  	fdwroutine->ReScanForeignScan = fileReScanForeignScan;
  	fdwroutine->EndForeignScan = fileEndForeignScan;
+ 	fdwroutine->AnalyzeForeignTable = fileAnalyzeForeignTable;
  
  	PG_RETURN_POINTER(fdwroutine);
  }
*************** fileReScanForeignScan(ForeignScanState *
*** 575,580 ****
--- 583,600 ----
  }
  
  /*
+  * fileAnalyzeForeignTable
+  *		Analyze foreign table
+  */
+ static void
+ fileAnalyzeForeignTable(Relation onerel, VacuumStmt *vacstmt, int elevel)
+ {
+ 	do_analyze_rel(onerel, vacstmt,
+ 				   elevel, false,
+ 				   acquire_sample_rows);
+ }
+ 
+ /*
   * Estimate costs of scanning a foreign table.
   */
  static void
*************** estimate_costs(PlannerInfo *root, RelOpt
*** 584,590 ****
  {
  	struct stat stat_buf;
  	BlockNumber pages;
! 	int			tuple_width;
  	double		ntuples;
  	double		nrows;
  	Cost		run_cost = 0;
--- 604,611 ----
  {
  	struct stat stat_buf;
  	BlockNumber pages;
! 	BlockNumber	relpages;
! 	double		reltuples;
  	double		ntuples;
  	double		nrows;
  	Cost		run_cost = 0;
*************** estimate_costs(PlannerInfo *root, RelOpt
*** 604,619 ****
  	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
--- 625,658 ----
  	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
*************** estimate_costs(PlannerInfo *root, RelOpt
*** 645,647 ****
--- 684,872 ----
  	run_cost += cpu_per_tuple * ntuples;
  	*total_cost = *startup_cost + run_cost;
  }
+ 
+ /*
+  * 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 valid 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
+ acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
+ 					double *totalrows, double *totaldeadrows,
+ 					BlockNumber *totalpages, int elevel)
+ {
+ 	int			numrows = 0;
+ 	int			invalrows = 0; /* total # rows violating
+ 								  the NOT NULL constraints */
+ 	double		validrows = 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;
+ 	char	   *filename;
+ 	struct stat	stat_buf;
+ 	List	   *options;
+ 	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));
+ 
+ 	/* Fetch options of foreign table */
+ 	fileGetOptions(RelationGetRelid(onerel), &filename, &options);
+ 
+ 	/*
+ 	 * 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);
+ 
+ 	/* Set up callback to identify error line number. */
+ 	errcontext.callback = CopyFromErrorCallback;
+ 	errcontext.arg = (void *) cstate;
+ 	errcontext.previous = error_context_stack;
+ 	error_context_stack = &errcontext;
+ 
+ 	for (;;)
+ 	{
+ 		sample_it = true;
+ 
+ 		/*
+ 		 * Check for user-requested abort.
+ 		 */
+ 		CHECK_FOR_INTERRUPTS();
+ 
+ 		found = NextCopyFrom(cstate, NULL, values, nulls, NULL);
+ 
+ 		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 &&
+ 					heap_attisnull(tuple, attrChk))
+ 				{
+ 					sample_it = false;
+ 					break;
+ 				}
+ 			}
+ 		}
+ 
+ 		if (!sample_it)
+ 		{
+ 			invalrows += 1;
+ 			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)
+ 			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(validrows, 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]);
+ 				rows[k] = heap_copytuple(tuple);
+ 			}
+ 
+ 			rowstoskip -= 1;
+ 		}
+ 
+ 		validrows += 1;
+ 		heap_freetuple(tuple);
+ 	}
+ 
+ 	/* Remove error callback. */
+ 	error_context_stack = errcontext.previous;
+ 
+ 	*totalrows = validrows;
+ 	*totaldeadrows = 0;
+ 
+ 	EndCopyFrom(cstate);
+ 
+ 	pfree(values);
+ 	pfree(nulls);
+ 
+ 	/*
+ 	 * Emit some interesting relation info
+ 	 */
+ 	ereport(elevel,
+ 			(errmsg("\"%s\": scanned, "
+ 					"containing %d valid rows and %d invalid rows; "
+ 					"%d rows in sample, %d total rows",
+ 					RelationGetRelationName(onerel),
+ 					(int) validrows, invalrows,
+ 					numrows, (int) *totalrows)));
+ 
+ 	return numrows;
+ }
diff --git a/contrib/file_fdw/input/file_fdw.source b/contrib/file_fdw/input/file_fdw.source
index 8e3d553..21b6fb4 100644
*** a/contrib/file_fdw/input/file_fdw.source
--- b/contrib/file_fdw/input/file_fdw.source
*************** EXECUTE st(100);
*** 111,116 ****
--- 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;
  
diff --git a/contrib/file_fdw/output/file_fdw.source b/contrib/file_fdw/output/file_fdw.source
index 84f0750..fe0d67f 100644
*** a/contrib/file_fdw/output/file_fdw.source
--- b/contrib/file_fdw/output/file_fdw.source
*************** EXECUTE st(100);
*** 174,179 ****
--- 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    
diff --git a/doc/src/sgml/fdwhandler.sgml b/doc/src/sgml/fdwhandler.sgml
index 76ff243..7d6443a 100644
*** a/doc/src/sgml/fdwhandler.sgml
--- b/doc/src/sgml/fdwhandler.sgml
*************** EndForeignScan (ForeignScanState *node);
*** 228,233 ****
--- 228,257 ----
      </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 catalogs.
+      This is optional, and if implemented, called when <command>ANALYZE
+      </> command is run.
+      The statistics are used by the query planner in order to make good
+      choices of query plans.
+      The function can be implemented by writing a sampling function that
+      acquires a random sample of rows from an external data source and
+      then by calling <function>do_analyze_rel</>, where you should pass
+      the sampling function as an argument.
+      Or the function can be directly implemented to get the statistics
+      from an external data source, transform it if neccesary, and store
+      it in the pg_class and pg_statistics system catalogs.
+      The function must be set to NULL if it isn't implemented.
+     </para>
+ 
+     <para>
       The <structname>FdwRoutine</> and <structname>FdwPlan</> struct types
       are declared in <filename>src/include/foreign/fdwapi.h</>, which see
       for additional details.
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 03cc6c9..82795d1 100644
*** a/doc/src/sgml/maintenance.sgml
--- b/doc/src/sgml/maintenance.sgml
***************
*** 279,284 ****
--- 279,288 ----
      <command>ANALYZE</> strictly as a function of the number of rows
      inserted or updated; it has no knowledge of whether that will lead
      to meaningful statistical changes.
+     Note that the autovacuum daemon does not issue <command>ANALYZE</>
+     commands on foreign tables.  It is recommended to run manually-managed
+     <command>ANALYZE</> commands as needed, which typically are executed
+     according to a schedule by cron or Task Scheduler scripts.
     </para>
  
     <para>
diff --git a/doc/src/sgml/ref/alter_foreign_table.sgml b/doc/src/sgml/ref/alter_foreign_table.sgml
index 5c7a86f..9fbb108 100644
*** a/doc/src/sgml/ref/alter_foreign_table.sgml
--- b/doc/src/sgml/ref/alter_foreign_table.sgml
*************** ALTER FOREIGN TABLE <replaceable class="
*** 36,41 ****
--- 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>'] [, ... ])
*************** ALTER FOREIGN TABLE <replaceable class="
*** 94,99 ****
--- 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 a per-attribute option.  Currently, the only defined
+       per-attribute option is <literal>n_distinct</>, which overrides
+       the number-of-distinct-values estimates made by subsequent
+       <xref linkend="sql-analyze"> operations. 
+       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>
diff --git a/doc/src/sgml/ref/analyze.sgml b/doc/src/sgml/ref/analyze.sgml
index 7545fa5..fe13b2b 100644
*** a/doc/src/sgml/ref/analyze.sgml
--- b/doc/src/sgml/ref/analyze.sgml
*************** ANALYZE [ VERBOSE ] [ <replaceable class
*** 39,47 ****
  
    <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>
  
--- 39,49 ----
  
    <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.  For a foreign table, it is
!    necessary to specify the name of 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>
  
*************** ANALYZE [ VERBOSE ] [ <replaceable class
*** 63,69 ****
      <listitem>
       <para>
        The name (possibly schema-qualified) of a specific table to
!       analyze. Defaults to all tables in the current database.
       </para>
      </listitem>
     </varlistentry>
--- 65,72 ----
      <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>
*************** ANALYZE [ VERBOSE ] [ <replaceable class
*** 137,143 ****
     In rare situations, this non-determinism will cause the planner's
     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.
    </para>
  
    <para>
--- 140,148 ----
     In rare situations, this non-determinism will cause the planner's
     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 on foreign tables depends on the implementation of
!    the foreign data wrapper via which such tables are attached.
    </para>
  
    <para>
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index c3d3958..fa5fa7e 100644
*** a/src/backend/commands/analyze.c
--- b/src/backend/commands/analyze.c
***************
*** 23,28 ****
--- 23,29 ----
  #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"
***************
*** 30,35 ****
--- 31,38 ----
  #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"
*************** typedef struct AnlIndexData
*** 78,91 ****
  int			default_statistics_target = 100;
  
  /* A few variables that don't seem worth passing around as parameters */
- static int	elevel = -1;
- 
  static MemoryContext anl_context = NULL;
  
  static BufferAccessStrategy vac_strategy;
  
  
- static void do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, bool inh);
  static void BlockSampler_Init(BlockSampler bs, BlockNumber nblocks,
  				  int samplesize);
  static bool BlockSampler_HasMore(BlockSampler bs);
--- 81,91 ----
*************** static void compute_index_stats(Relation
*** 96,110 ****
  					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);
--- 96,110 ----
  					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,
! 							   BlockNumber *totalpages, int elevel);
  static int acquire_inherited_sample_rows(Relation onerel,
  							  HeapTuple *rows, int targrows,
! 							  double *totalrows, double *totaldeadrows,
! 							  BlockNumber *totalpages, int elevel);
! static int	compare_rows(const void *a, const void *b);
  static void update_attstats(Oid relid, bool inh,
  				int natts, VacAttrStats **vacattrstats);
  static Datum std_fetch_func(VacAttrStatsP stats, int rownum, bool *isNull);
*************** static bool std_typanalyze(VacAttrStats 
*** 119,125 ****
--- 119,127 ----
  void
  analyze_rel(Oid relid, VacuumStmt *vacstmt, BufferAccessStrategy bstrategy)
  {
+ 	int			elevel;
  	Relation	onerel;
+ 	FdwRoutine *fdwroutine;
  
  	/* Set up static variables */
  	if (vacstmt->options & VACOPT_VERBOSE)
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 184,193 ****
  	}
  
  	/*
! 	 * 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))
--- 186,197 ----
  	}
  
  	/*
! 	 * Check that it's a plain table or 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))
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 211,217 ****
  	}
  
  	/*
! 	 * We can ANALYZE any table except pg_statistic. See update_attstats
  	 */
  	if (RelationGetRelid(onerel) == StatisticRelationId)
  	{
--- 215,223 ----
  	}
  
  	/*
! 	 * We can ANALYZE any table except pg_statistic.  See update_attstats.  In
! 	 * addition, we can ANALYZE foreign tables if AnalyzeForeignTable callback
! 	 * routines of underlying foreign-data wrappers are implemented.
  	 */
  	if (RelationGetRelid(onerel) == StatisticRelationId)
  	{
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 219,224 ****
--- 225,244 ----
  		return;
  	}
  
+ 	if (onerel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
+ 	{
+  		fdwroutine = GetFdwRoutineByRelId(RelationGetRelid(onerel));
+ 
+ 		if (fdwroutine->AnalyzeForeignTable == NULL)
+ 		{
+ 			ereport(WARNING,
+ 					(errmsg("skipping \"%s\" --- underlying foreign-data wrapper cannot analyze it",
+ 							RelationGetRelationName(onerel))));
+ 			relation_close(onerel, ShareUpdateExclusiveLock);
+ 			return;
+ 		}
+ 	}
+ 
  	/*
  	 * OK, let's do it.  First let other backends know I'm in ANALYZE.
  	 */
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 226,241 ****
  	MyPgXact->vacuumFlags |= PROC_IN_ANALYZE;
  	LWLockRelease(ProcArrayLock);
  
! 	/*
! 	 * 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
--- 246,283 ----
  	MyPgXact->vacuumFlags |= PROC_IN_ANALYZE;
  	LWLockRelease(ProcArrayLock);
  
! 	if (onerel->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
! 	{
! 		ereport(elevel,
! 				(errmsg("analyzing \"%s.%s\"",
! 						get_namespace_name(RelationGetNamespace(onerel)),
! 						RelationGetRelationName(onerel))));
! 		fdwroutine->AnalyzeForeignTable(onerel, vacstmt, elevel);
! 	}
! 	else
! 	{
! 		/*
! 		 * Do the normal non-recursive ANALYZE.
! 		 */
! 		ereport(elevel,
! 				(errmsg("analyzing \"%s.%s\"",
! 						get_namespace_name(RelationGetNamespace(onerel)),
! 						RelationGetRelationName(onerel))));
! 		do_analyze_rel(onerel, vacstmt, elevel, false, acquire_sample_rows);
  
! 		/*
! 		 * If there are child tables, do recursive ANALYZE.
! 		 */
! 		if (onerel->rd_rel->relhassubclass)
! 		{
! 			ereport(elevel,
! 					(errmsg("analyzing \"%s.%s\" inheritance tree",
! 							get_namespace_name(RelationGetNamespace(onerel)),
! 							RelationGetRelationName(onerel))));
! 			do_analyze_rel(onerel, vacstmt, elevel, true,
! 						   acquire_inherited_sample_rows);
! 		}
! 	}
  
  	/*
  	 * Close source relation now, but keep lock so that no one deletes it
*************** analyze_rel(Oid relid, VacuumStmt *vacst
*** 257,264 ****
  /*
   *	do_analyze_rel() -- analyze one relation, recursively or not
   */
! static void
! do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, bool inh)
  {
  	int			attr_cnt,
  				tcnt,
--- 299,307 ----
  /*
   *	do_analyze_rel() -- analyze one relation, recursively or not
   */
! void
! do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, int elevel, 
! 			   bool inh, SampleRowAcquireFunc acquirefunc)
  {
  	int			attr_cnt,
  				tcnt,
*************** do_analyze_rel(Relation onerel, VacuumSt
*** 273,278 ****
--- 316,322 ----
  				numrows;
  	double		totalrows,
  				totaldeadrows;
+ 	BlockNumber totalpages;
  	HeapTuple  *rows;
  	PGRUsage	ru0;
  	TimestampTz starttime = 0;
*************** do_analyze_rel(Relation onerel, VacuumSt
*** 281,297 ****
  	int			save_sec_context;
  	int			save_nestlevel;
  
- 	if (inh)
- 		ereport(elevel,
- 				(errmsg("analyzing \"%s.%s\" inheritance tree",
- 						get_namespace_name(RelationGetNamespace(onerel)),
- 						RelationGetRelationName(onerel))));
- 	else
- 		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.
--- 325,330 ----
*************** do_analyze_rel(Relation onerel, VacuumSt
*** 449,459 ****
  	 */
  	rows = (HeapTuple *) palloc(targrows * sizeof(HeapTuple));
  	if (inh)
! 		numrows = acquire_inherited_sample_rows(onerel, rows, targrows,
! 												&totalrows, &totaldeadrows);
  	else
! 		numrows = acquire_sample_rows(onerel, rows, targrows,
! 									  &totalrows, &totaldeadrows);
  
  	/*
  	 * Compute the statistics.	Temporary results during the calculations for
--- 482,494 ----
  	 */
  	rows = (HeapTuple *) palloc(targrows * sizeof(HeapTuple));
  	if (inh)
! 		numrows = acquirefunc(onerel, rows, targrows,
! 							  &totalrows, &totaldeadrows,
! 							  NULL, elevel);
  	else
! 		numrows = acquirefunc(onerel, rows, targrows,
! 							  &totalrows, &totaldeadrows,
! 							  &totalpages, elevel);
  
  	/*
  	 * Compute the statistics.	Temporary results during the calculations for
*************** do_analyze_rel(Relation onerel, VacuumSt
*** 534,540 ****
  	 */
  	if (!inh)
  		vac_update_relstats(onerel,
! 							RelationGetNumberOfBlocks(onerel),
  							totalrows,
  							visibilitymap_count(onerel),
  							hasindex,
--- 569,575 ----
  	 */
  	if (!inh)
  		vac_update_relstats(onerel,
! 							totalpages,
  							totalrows,
  							visibilitymap_count(onerel),
  							hasindex,
*************** BlockSampler_Next(BlockSampler bs)
*** 1017,1023 ****
   */
  static int
  acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
! 					double *totalrows, double *totaldeadrows)
  {
  	int			numrows = 0;	/* # rows now in reservoir */
  	double		samplerows = 0; /* total # rows collected */
--- 1052,1059 ----
   */
  static int
  acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
! 					double *totalrows, double *totaldeadrows,
! 					BlockNumber *totalpages, int elevel)
  {
  	int			numrows = 0;	/* # rows now in reservoir */
  	double		samplerows = 0; /* total # rows collected */
*************** acquire_sample_rows(Relation onerel, Hea
*** 1032,1037 ****
--- 1068,1075 ----
  	Assert(targrows > 0);
  
  	totalblocks = RelationGetNumberOfBlocks(onerel);
+ 	if (totalpages)
+ 		*totalpages = totalblocks;
  
  	/* Need a cutoff xmin for HeapTupleSatisfiesVacuum */
  	OldestXmin = GetOldestXmin(onerel->rd_rel->relisshared, true);
*************** acquire_sample_rows(Relation onerel, Hea
*** 1254,1260 ****
  }
  
  /* Select a random value R uniformly distributed in (0 - 1) */
! static double
  random_fract(void)
  {
  	return ((double) random() + 1) / ((double) MAX_RANDOM_VALUE + 2);
--- 1292,1298 ----
  }
  
  /* Select a random value R uniformly distributed in (0 - 1) */
! double
  random_fract(void)
  {
  	return ((double) random() + 1) / ((double) MAX_RANDOM_VALUE + 2);
*************** random_fract(void)
*** 1274,1287 ****
   * 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;
--- 1312,1325 ----
   * 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;
*************** compare_rows(const void *a, const void *
*** 1397,1403 ****
   */
  static int
  acquire_inherited_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
! 							  double *totalrows, double *totaldeadrows)
  {
  	List	   *tableOIDs;
  	Relation   *rels;
--- 1435,1442 ----
   */
  static int
  acquire_inherited_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
! 							  double *totalrows, double *totaldeadrows,
! 							  BlockNumber *totalpages, int elevel)
  {
  	List	   *tableOIDs;
  	Relation   *rels;
*************** acquire_inherited_sample_rows(Relation o
*** 1460,1465 ****
--- 1499,1506 ----
  		totalblocks += relblocks[nrels];
  		nrels++;
  	}
+ 	if (totalpages)
+ 	  *totalpages = totalblocks;
  
  	/*
  	 * Now sample rows from each relation, proportionally to its fraction of
*************** acquire_inherited_sample_rows(Relation o
*** 1493,1499 ****
  												rows + numrows,
  												childtargrows,
  												&trows,
! 												&tdrows);
  
  				/* We may need to convert from child's rowtype to parent's */
  				if (childrows > 0 &&
--- 1534,1542 ----
  												rows + numrows,
  												childtargrows,
  												&trows,
! 												&tdrows,
! 												NULL,
! 												elevel);
  
  				/* We may need to convert from child's rowtype to parent's */
  				if (childrows > 0 &&
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 1ee201c..9e7c063 100644
*** a/src/backend/commands/tablecmds.c
--- b/src/backend/commands/tablecmds.c
*************** static void ATPrepSetStatistics(Relation
*** 317,322 ****
--- 317,324 ----
  					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,
*************** ATPrepCmd(List **wqueue, Relation rel, A
*** 2915,2921 ****
  			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;
--- 2917,2924 ----
  			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;
*************** ATPrepSetStatistics(Relation rel, const 
*** 4851,4860 ****
  	 * 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",
  						RelationGetRelationName(rel))));
  
  	/* Permissions checks */
--- 4854,4864 ----
  	 * 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, index or foreign table",
  						RelationGetRelationName(rel))));
  
  	/* Permissions checks */
*************** ATExecSetStatistics(Relation rel, const 
*** 4923,4928 ****
--- 4927,4952 ----
  }
  
  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_strcasecmp(def->defname, "n_distinct_inherited") == 0)
+ 				ereport(ERROR,
+ 						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ 						 errmsg("cannot set \"n_distinct_inherited\" for foreign tables")));
+ 		}
+ 	}
+ }
+ 
+ static void
  ATExecSetOptions(Relation rel, const char *colName, Node *options,
  				 bool isReset, LOCKMODE lockmode)
  {
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index dcafdd2..802abf2 100644
*** a/src/bin/psql/describe.c
--- b/src/bin/psql/describe.c
*************** describeOneTableDetails(const char *sche
*** 1099,1105 ****
  	bool		printTableInitialized = false;
  	int			i;
  	char	   *view_def = NULL;
! 	char	   *headers[6];
  	char	  **seq_values = NULL;
  	char	  **modifiers = NULL;
  	char	  **ptr;
--- 1099,1105 ----
  	bool		printTableInitialized = false;
  	int			i;
  	char	   *view_def = NULL;
! 	char	   *headers[7];
  	char	  **seq_values = NULL;
  	char	  **modifiers = NULL;
  	char	  **ptr;
*************** describeOneTableDetails(const char *sche
*** 1390,1396 ****
  	if (verbose)
  	{
  		headers[cols++] = gettext_noop("Storage");
! 		if (tableinfo.relkind == 'r')
  			headers[cols++] = gettext_noop("Stats target");
  		/* Column comments, if the relkind supports this feature. */
  		if (tableinfo.relkind == 'r' || tableinfo.relkind == 'v' ||
--- 1390,1396 ----
  	if (verbose)
  	{
  		headers[cols++] = gettext_noop("Storage");
! 		if (tableinfo.relkind == 'r' || tableinfo.relkind == 'f')
  			headers[cols++] = gettext_noop("Stats target");
  		/* Column comments, if the relkind supports this feature. */
  		if (tableinfo.relkind == 'r' || tableinfo.relkind == 'v' ||
*************** describeOneTableDetails(const char *sche
*** 1493,1499 ****
  							  false, false);
  
  			/* Statistics target, if the relkind supports this feature */
! 			if (tableinfo.relkind == 'r')
  			{
  				printTableAddCell(&cont, PQgetvalue(res, i, firstvcol + 1),
  								  false, false);
--- 1493,1499 ----
  							  false, false);
  
  			/* Statistics target, if the relkind supports this feature */
! 			if (tableinfo.relkind == 'r' || tableinfo.relkind == 'f')
  			{
  				printTableAddCell(&cont, PQgetvalue(res, i, firstvcol + 1),
  								  false, false);
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index bb0fa09..1507a61 100644
*** a/src/bin/psql/tab-complete.c
--- b/src/bin/psql/tab-complete.c
*************** static const SchemaQuery Query_for_list_
*** 399,404 ****
--- 399,419 ----
  	NULL
  };
  
+ static const SchemaQuery Query_for_list_of_tf = {
+ 	/* catname */
+ 	"pg_catalog.pg_class c",
+ 	/* selcondition */
+ 	"c.relkind IN ('r', 'f')",
+ 	/* viscondition */
+ 	"pg_catalog.pg_table_is_visible(c.oid)",
+ 	/* namespace */
+ 	"c.relnamespace",
+ 	/* result */
+ 	"pg_catalog.quote_ident(c.relname)",
+ 	/* qualresult */
+ 	NULL
+ };
+ 
  static const SchemaQuery Query_for_list_of_views = {
  	/* catname */
  	"pg_catalog.pg_class c",
*************** psql_completion(char *text, int start, i
*** 2769,2775 ****
  /* ANALYZE */
  	/* If the previous word is ANALYZE, produce list of tables */
  	else if (pg_strcasecmp(prev_wd, "ANALYZE") == 0)
! 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_tables, NULL);
  
  /* WHERE */
  	/* Simple case of the word before the where being the table name */
--- 2784,2790 ----
  /* ANALYZE */
  	/* If the previous word is ANALYZE, produce list of tables */
  	else if (pg_strcasecmp(prev_wd, "ANALYZE") == 0)
! 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_tf, NULL);
  
  /* WHERE */
  	/* Simple case of the word before the where being the table name */
diff --git a/src/include/commands/vacuum.h b/src/include/commands/vacuum.h
index d8fd0ca..0c24e2d 100644
*** a/src/include/commands/vacuum.h
--- b/src/include/commands/vacuum.h
*************** extern void lazy_vacuum_rel(Relation one
*** 165,171 ****
--- 165,182 ----
  				BufferAccessStrategy bstrategy);
  
  /* in commands/analyze.c */
+ typedef int (*SampleRowAcquireFunc) (Relation onerel, HeapTuple *rows,
+ 									 int targrows,
+ 									 double *totalrows, double *totaldeadrows,
+ 									 BlockNumber *totalpages, int elevel);
+ 
  extern void analyze_rel(Oid relid, VacuumStmt *vacstmt,
  			BufferAccessStrategy bstrategy);
+ extern void do_analyze_rel(Relation onerel, VacuumStmt *vacstmt, int elevel, 
+ 						   bool inh, SampleRowAcquireFunc acquirefunc);
+ extern double random_fract(void);
+ extern double init_selection_state(int n);
+ extern double get_next_S(double t, int n, double *stateptr);
+ 
  
  #endif   /* VACUUM_H */
diff --git a/src/include/foreign/fdwapi.h b/src/include/foreign/fdwapi.h
index 3378ba9..3543f15 100644
*** 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;
*************** typedef void (*ReScanForeignScan_functio
*** 68,73 ****
--- 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
*************** typedef struct FdwRoutine
*** 82,93 ****
--- 87,109 ----
  {
  	NodeTag		type;
  
+ 	/*
+ 	 * These handlers are required to execute simple scans on a foreign
+ 	 * table.  If any of them was set to NULL, scans on a foreign table
+ 	 * managed by FDW would fail.
+ 	 */
  	PlanForeignScan_function PlanForeignScan;
  	ExplainForeignScan_function ExplainForeignScan;
  	BeginForeignScan_function BeginForeignScan;
  	IterateForeignScan_function IterateForeignScan;
  	ReScanForeignScan_function ReScanForeignScan;
  	EndForeignScan_function EndForeignScan;
+ 
+ 	/*
+ 	 * Handlers below are optional.  You can set any of them to NULL to
+ 	 * tell PostgreSQL that FDW doesn't have the capability.
+ 	 */
+ 	AnalyzeForeignTable_function AnalyzeForeignTable;
  } FdwRoutine;
  
  
diff --git a/src/test/regress/expected/foreign_data.out b/src/test/regress/expected/foreign_data.out
index 122e285..48a07f3 100644
*** a/src/test/regress/expected/foreign_data.out
--- b/src/test/regress/expected/foreign_data.out
*************** CREATE FOREIGN TABLE ft1 (
*** 678,689 ****
  COMMENT ON FOREIGN TABLE ft1 IS 'ft1';
  COMMENT ON COLUMN ft1.c1 IS 'ft1.c1';
  \d+ ft1
!                                Foreign table "public.ft1"
!  Column |  Type   | Modifiers |          FDW Options           | Storage  | Description 
! --------+---------+-----------+--------------------------------+----------+-------------
!  c1     | integer | not null  | ("param 1" 'val1')             | plain    | ft1.c1
!  c2     | text    |           | (param2 'val2', param3 'val3') | extended | 
!  c3     | date    |           |                                | plain    | 
  Server: s0
  FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
  Has OIDs: no
--- 678,689 ----
  COMMENT ON FOREIGN TABLE ft1 IS 'ft1';
  COMMENT ON COLUMN ft1.c1 IS 'ft1.c1';
  \d+ ft1
!                                       Foreign table "public.ft1"
!  Column |  Type   | Modifiers |          FDW Options           | Storage  | Stats target | Description 
! --------+---------+-----------+--------------------------------+----------+--------------+-------------
!  c1     | integer | not null  | ("param 1" 'val1')             | plain    |              | ft1.c1
!  c2     | text    |           | (param2 'val2', param3 'val3') | extended |              | 
!  c3     | date    |           |                                | plain    |              | 
  Server: s0
  FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
  Has OIDs: no
*************** ERROR:  cannot alter system column "xmin
*** 729,747 ****
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c7 OPTIONS (ADD p1 'v1', ADD p2 'v2'),
                          ALTER COLUMN c8 OPTIONS (ADD p1 'v1', ADD p2 'v2');
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 OPTIONS (SET p2 'V2', DROP p1);
  \d+ ft1
!                                Foreign table "public.ft1"
!  Column |  Type   | Modifiers |          FDW Options           | Storage  | Description 
! --------+---------+-----------+--------------------------------+----------+-------------
!  c1     | integer | not null  | ("param 1" 'val1')             | plain    | 
!  c2     | text    |           | (param2 'val2', param3 'val3') | extended | 
!  c3     | date    |           |                                | plain    | 
!  c4     | integer |           |                                | plain    | 
!  c6     | integer | not null  |                                | plain    | 
!  c7     | integer |           | (p1 'v1', p2 'v2')             | plain    | 
!  c8     | text    |           | (p2 'V2')                      | extended | 
!  c9     | integer |           |                                | plain    | 
!  c10    | integer |           | (p1 'v1')                      | plain    | 
  Server: s0
  FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
  Has OIDs: no
--- 729,752 ----
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c7 OPTIONS (ADD p1 'v1', ADD p2 'v2'),
                          ALTER COLUMN c8 OPTIONS (ADD p1 'v1', ADD p2 'v2');
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 OPTIONS (SET p2 'V2', DROP p1);
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET STATISTICS 10000;
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct = 100);
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct_inherited = 100); -- ERROR
+ ERROR:  cannot set "n_distinct_inherited" for foreign tables
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STATISTICS -1;
  \d+ ft1
!                                       Foreign table "public.ft1"
!  Column |  Type   | Modifiers |          FDW Options           | Storage  | Stats target | Description 
! --------+---------+-----------+--------------------------------+----------+--------------+-------------
!  c1     | integer | not null  | ("param 1" 'val1')             | plain    | 10000        | 
!  c2     | text    |           | (param2 'val2', param3 'val3') | extended |              | 
!  c3     | date    |           |                                | plain    |              | 
!  c4     | integer |           |                                | plain    |              | 
!  c6     | integer | not null  |                                | plain    |              | 
!  c7     | integer |           | (p1 'v1', p2 'v2')             | plain    |              | 
!  c8     | text    |           | (p2 'V2')                      | extended |              | 
!  c9     | integer |           |                                | plain    |              | 
!  c10    | integer |           | (p1 'v1')                      | plain    |              | 
  Server: s0
  FDW Options: (delimiter ',', quote '"', "be quoted" 'value')
  Has OIDs: no
diff --git a/src/test/regress/sql/foreign_data.sql b/src/test/regress/sql/foreign_data.sql
index e99e707..5908ff3 100644
*** a/src/test/regress/sql/foreign_data.sql
--- b/src/test/regress/sql/foreign_data.sql
*************** ALTER FOREIGN TABLE ft1 ALTER COLUMN xmi
*** 306,311 ****
--- 306,315 ----
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c7 OPTIONS (ADD p1 'v1', ADD p2 'v2'),
                          ALTER COLUMN c8 OPTIONS (ADD p1 'v1', ADD p2 'v2');
  ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 OPTIONS (SET p2 'V2', DROP p1);
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET STATISTICS 10000;
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct = 100);
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c1 SET (n_distinct_inherited = 100); -- ERROR
+ ALTER FOREIGN TABLE ft1 ALTER COLUMN c8 SET STATISTICS -1;
  \d+ ft1
  -- can't change the column type if it's used elsewhere
  CREATE TABLE use_ft1_column_type (x ft1);

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