[Quan Zongliang <quanzongliang@yeah.net>]

If the block size is 32k, the function page_header of the pageinspect 
module returns negative numbers:

postgres=# select * from page_header(get_raw_page('t1',0));
     lsn    | checksum | flags | lower | upper | special | pagesize | 
version | prune_xid
-----------+----------+-------+-------+-------+---------+----------+---------+-----------
  0/174CF58 |        0 |     0 |    28 | 32736 |  -32768 |   -32768 | 
    4 |         0
(1 row)


This patch changes the output parameters lower, upper, special and 
pagesize to int32.

postgres=# select * from page_header(get_raw_page('t1',0));
     lsn    | checksum | flags | lower | upper | special | pagesize | 
version | prune_xid
-----------+----------+-------+-------+-------+---------+----------+---------+-----------
  0/19EA640 |        0 |     0 |    28 | 32736 |   32768 |    32768 | 
    4 |         0
(1 row)


--
Quan Zongliang

Attachments:

pageinspect.patch (text/plain, 1.5K) download
diff --git a/contrib/pageinspect/pageinspect--1.5.sql b/contrib/pageinspect/pageinspect--1.5.sql
index 1e40c3c97e..f71eff19c5 100644
--- a/contrib/pageinspect/pageinspect--1.5.sql
+++ b/contrib/pageinspect/pageinspect--1.5.sql
@@ -23,10 +23,10 @@ CREATE FUNCTION page_header(IN page bytea,
     OUT lsn pg_lsn,
     OUT checksum smallint,
     OUT flags smallint,
-    OUT lower smallint,
-    OUT upper smallint,
-    OUT special smallint,
-    OUT pagesize smallint,
+    OUT lower int,
+    OUT upper int,
+    OUT special int,
+    OUT pagesize int,
     OUT version smallint,
     OUT prune_xid xid)
 AS 'MODULE_PATHNAME', 'page_header'
diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c
index 7272b21016..af04c1a688 100644
--- a/contrib/pageinspect/rawpage.c
+++ b/contrib/pageinspect/rawpage.c
@@ -316,10 +316,10 @@ page_header(PG_FUNCTION_ARGS)
 		values[0] = LSNGetDatum(lsn);
 	values[1] = UInt16GetDatum(page->pd_checksum);
 	values[2] = UInt16GetDatum(page->pd_flags);
-	values[3] = UInt16GetDatum(page->pd_lower);
-	values[4] = UInt16GetDatum(page->pd_upper);
-	values[5] = UInt16GetDatum(page->pd_special);
-	values[6] = UInt16GetDatum(PageGetPageSize(page));
+	values[3] = Int32GetDatum(page->pd_lower);
+	values[4] = Int32GetDatum(page->pd_upper);
+	values[5] = Int32GetDatum(page->pd_special);
+	values[6] = Int32GetDatum(PageGetPageSize(page));
 	values[7] = UInt16GetDatum(PageGetPageLayoutVersion(page));
 	values[8] = TransactionIdGetDatum(page->pd_prune_xid);