Re: Assert in pageinspect with NULL pages

BRIN can also crash if passed a non-brin index.

I've been sitting on this one for awhile. Feel free to include it in your
patchset.

commit 08010a6037fc4e24a9ba05e5386e766f4310d35e
Author: Justin Pryzby <pryzbyj(at)telsasoft(dot)com>
Date: Tue Jan 19 00:25:15 2021 -0600

pageinspect: brin_page_items(): check that given relation is not only an index, but a brin one

diff --git a/contrib/pageinspect/brinfuncs.c b/contrib/pageinspect/brinfuncs.c
index f1e64a39ef2..3de6dd943ef 100644
--- a/contrib/pageinspect/brinfuncs.c
+++ b/contrib/pageinspect/brinfuncs.c
@@ -16,6 +16,7 @@
#include "access/brin_tuple.h"
#include "access/htup_details.h"
#include "catalog/index.h"
+#include "catalog/pg_am.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "lib/stringinfo.h"
@@ -59,7 +60,7 @@ brin_page_type(PG_FUNCTION_ARGS)
if (raw_page_size != BLCKSZ)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("input page too small"),
+ errmsg("input page wrong size"),
errdetail("Expected size %d, got %d",
BLCKSZ, raw_page_size)));

@@ -97,7 +98,7 @@ verify_brin_page(bytea *raw_page, uint16 type, const char *strtype)
if (raw_page_size != BLCKSZ)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("input page too small"),
+ errmsg("input page wrong size"),
errdetail("Expected size %d, got %d",
BLCKSZ, raw_page_size)));

@@ -169,7 +170,14 @@ brin_page_items(PG_FUNCTION_ARGS)
MemoryContextSwitchTo(oldcontext);

indexRel = index_open(indexRelid, AccessShareLock);
- bdesc = brin_build_desc(indexRel);
+
+ /* Must be a BRIN index */
+ if (indexRel->rd_rel->relkind != RELKIND_INDEX ||
+ indexRel->rd_rel->relam != BRIN_AM_OID)
+ ereport(ERROR,
+ (errcode(ERRCODE_WRONG_OBJECT_TYPE),
+ errmsg("\"%s\" is not a BRIN index",
+ RelationGetRelationName(indexRel))));

/* minimally verify the page we got */
page = verify_brin_page(raw_page, BRIN_PAGETYPE_REGULAR, "regular");
@@ -178,6 +186,7 @@ brin_page_items(PG_FUNCTION_ARGS)
* Initialize output functions for all indexed datatypes; simplifies
* calling them later.
*/
+ bdesc = brin_build_desc(indexRel);
columns = palloc(sizeof(brin_column_state *) * RelationGetDescr(indexRel)->natts);
for (attno = 1; attno <= bdesc->bd_tupdesc->natts; attno++)
{