Show empty BRIN ranges in brin_page_items

Commit 3581cbdcd6 added a flag to identify empty BRIN ranges. This adds
the new flag to brin_page_items() output.

This is kept as a separate commit as it should not be backpatched.

Reviewed-by: Justin Pryzby, Matthias van de Meent, Alvaro Herrera
Discussion: https://postgr.es/m/402430e4-7d9d-6cf1-09ef-464d80afff3b@enterprisedb.com

contrib/pageinspect/brinfuncs.c

@@ -201,8 +201,8 @@ brin_page_items(PG_FUNCTION_ARGS)
 	dtup = NULL;
 	for (;;)
 	{
-		Datum		values[7];
+		Datum		values[8];
-		bool		nulls[7] = {0};
+		bool		nulls[8] = {0};
 
 		/*
 		 * This loop is called once for every attribute of every tuple in the
@@ -239,6 +239,7 @@ brin_page_items(PG_FUNCTION_ARGS)
 			nulls[4] = true;
 			nulls[5] = true;
 			nulls[6] = true;
+			nulls[7] = true;
 		}
 		else
 		{
@@ -261,6 +262,7 @@ brin_page_items(PG_FUNCTION_ARGS)
 			values[3] = BoolGetDatum(dtup->bt_columns[att].bv_allnulls);
 			values[4] = BoolGetDatum(dtup->bt_columns[att].bv_hasnulls);
 			values[5] = BoolGetDatum(dtup->bt_placeholder);
+			values[6] = BoolGetDatum(dtup->bt_empty_range);
 			if (!dtup->bt_columns[att].bv_allnulls)
 			{
 				BrinValues *bvalues = &dtup->bt_columns[att];
@@ -286,12 +288,12 @@ brin_page_items(PG_FUNCTION_ARGS)
 				}
 				appendStringInfoChar(&s, '}');
 
-				values[6] = CStringGetTextDatum(s.data);
+				values[7] = CStringGetTextDatum(s.data);
 				pfree(s.data);
 			}
 			else
 			{
-				nulls[6] = true;
+				nulls[7] = true;
 			}
 		}
 

contrib/pageinspect/expected/brin.out

@@ -43,9 +43,9 @@ SELECT * FROM brin_revmap_data(get_raw_page('test1_a_idx', 1)) LIMIT 5;
 
 SELECT * FROM brin_page_items(get_raw_page('test1_a_idx', 2), 'test1_a_idx')
     ORDER BY blknum, attnum LIMIT 5;
- itemoffset | blknum | attnum | allnulls | hasnulls | placeholder |  value   
+ itemoffset | blknum | attnum | allnulls | hasnulls | placeholder | empty |  value   
-------------+--------+--------+----------+----------+-------------+----------
+------------+--------+--------+----------+----------+-------------+-------+----------
-          1 |      0 |      1 | f        | f        | f           | {1 .. 1}
+          1 |      0 |      1 | f        | f        | f           | f     | {1 .. 1}
 (1 row)
 
 -- Mask DETAIL messages as these are not portable across architectures.

contrib/pageinspect/pageinspect--1.11--1.12.sql

@@ -21,3 +21,20 @@ CREATE FUNCTION bt_multi_page_stats(IN relname text, IN blkno int8, IN blk_count
 RETURNS SETOF record
 AS 'MODULE_PATHNAME', 'bt_multi_page_stats'
 LANGUAGE C STRICT PARALLEL RESTRICTED;
+
+--
+-- add information about BRIN empty ranges
+--
+DROP FUNCTION brin_page_items(IN page bytea, IN index_oid regclass);
+CREATE FUNCTION brin_page_items(IN page bytea, IN index_oid regclass,
+    OUT itemoffset int,
+    OUT blknum int8,
+    OUT attnum int,
+    OUT allnulls bool,
+    OUT hasnulls bool,
+    OUT placeholder bool,
+    OUT empty bool,
+    OUT value text)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'brin_page_items'
+LANGUAGE C STRICT PARALLEL RESTRICTED;

doc/src/sgml/pageinspect.sgml

@@ -613,14 +613,14 @@ test=# SELECT * FROM brin_revmap_data(get_raw_page('brinidx', 2)) LIMIT 5;
 test=# SELECT * FROM brin_page_items(get_raw_page('brinidx', 5),
                                      'brinidx')
        ORDER BY blknum, attnum LIMIT 6;
- itemoffset | blknum | attnum | allnulls | hasnulls | placeholder |    value
+ itemoffset | blknum | attnum | allnulls | hasnulls | placeholder | empty |    value
-------------+--------+--------+----------+----------+-------------+--------------
+------------+--------+--------+----------+----------+-------------+-------+--------------
-        137 |      0 |      1 | t        | f        | f           |
+        137 |      0 |      1 | t        | f        | f           | f     |
-        137 |      0 |      2 | f        | f        | f           | {1 .. 88}
+        137 |      0 |      2 | f        | f        | f           | f     | {1 .. 88}
-        138 |      4 |      1 | t        | f        | f           |
+        138 |      4 |      1 | t        | f        | f           | f     |
-        138 |      4 |      2 | f        | f        | f           | {89 .. 176}
+        138 |      4 |      2 | f        | f        | f           | f     | {89 .. 176}
-        139 |      8 |      1 | t        | f        | f           |
+        139 |      8 |      1 | t        | f        | f           | f     |
-        139 |      8 |      2 | f        | f        | f           | {177 .. 264}
+        139 |      8 |      2 | f        | f        | f           | f     | {177 .. 264}
 </screen>
       The returned columns correspond to the fields in the
       <structname>BrinMemTuple</structname> and <structname>BrinValues</structname> structs.

src/test/modules/brin/expected/summarization-and-inprogress-insertion.out

@@ -2,9 +2,9 @@ Parsed test spec with 2 sessions
 
 starting permutation: s2check s1b s2b s1i s2summ s1c s2c s2check
 step s2check: SELECT * FROM brin_page_items(get_raw_page('brinidx', 2), 'brinidx'::regclass);
-itemoffset|blknum|attnum|allnulls|hasnulls|placeholder|value   
+itemoffset|blknum|attnum|allnulls|hasnulls|placeholder|empty|value   
-----------+------+------+--------+--------+-----------+--------
+----------+------+------+--------+--------+-----------+-----+--------
-         1|     0|     1|f       |t       |f          |{1 .. 1}
+         1|     0|     1|f       |t       |f          |f    |{1 .. 1}
 (1 row)
 
 step s1b: BEGIN ISOLATION LEVEL REPEATABLE READ;
@@ -24,18 +24,18 @@ brin_summarize_new_values
 step s1c: COMMIT;
 step s2c: COMMIT;
 step s2check: SELECT * FROM brin_page_items(get_raw_page('brinidx', 2), 'brinidx'::regclass);
-itemoffset|blknum|attnum|allnulls|hasnulls|placeholder|value      
+itemoffset|blknum|attnum|allnulls|hasnulls|placeholder|empty|value      
-----------+------+------+--------+--------+-----------+-----------
+----------+------+------+--------+--------+-----------+-----+-----------
-         1|     0|     1|f       |t       |f          |{1 .. 1}   
+         1|     0|     1|f       |t       |f          |f    |{1 .. 1}   
-         2|     1|     1|f       |f       |f          |{1 .. 1000}
+         2|     1|     1|f       |f       |f          |f    |{1 .. 1000}
 (2 rows)
 
 
 starting permutation: s2check s1b s1i s2vacuum s1c s2check
 step s2check: SELECT * FROM brin_page_items(get_raw_page('brinidx', 2), 'brinidx'::regclass);
-itemoffset|blknum|attnum|allnulls|hasnulls|placeholder|value   
+itemoffset|blknum|attnum|allnulls|hasnulls|placeholder|empty|value   
-----------+------+------+--------+--------+-----------+--------
+----------+------+------+--------+--------+-----------+-----+--------
-         1|     0|     1|f       |t       |f          |{1 .. 1}
+         1|     0|     1|f       |t       |f          |f    |{1 .. 1}
 (1 row)
 
 step s1b: BEGIN ISOLATION LEVEL REPEATABLE READ;
@@ -43,9 +43,9 @@ step s1i: INSERT INTO brin_iso VALUES (1000);
 step s2vacuum: VACUUM brin_iso;
 step s1c: COMMIT;
 step s2check: SELECT * FROM brin_page_items(get_raw_page('brinidx', 2), 'brinidx'::regclass);
-itemoffset|blknum|attnum|allnulls|hasnulls|placeholder|value      
+itemoffset|blknum|attnum|allnulls|hasnulls|placeholder|empty|value      
-----------+------+------+--------+--------+-----------+-----------
+----------+------+------+--------+--------+-----------+-----+-----------
-         1|     0|     1|f       |t       |f          |{1 .. 1}   
+         1|     0|     1|f       |t       |f          |f    |{1 .. 1}   
-         2|     1|     1|f       |f       |f          |{1 .. 1000}
+         2|     1|     1|f       |f       |f          |f    |{1 .. 1000}
 (2 rows)