1 files changed, 373 insertions, 0 deletions

diff --git a/contrib/pageinspect/gistfuncs.c b/contrib/pageinspect/gistfuncs.c
new file mode 100644
index 0000000..894d74f
--- /dev/null
+++ b/contrib/pageinspect/gistfuncs.c
@@ -0,0 +1,373 @@
+/*
+ * gistfuncs.c
+ *		Functions to investigate the content of GiST indexes
+ *
+ * Copyright (c) 2014-2022, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		contrib/pageinspect/gistfuncs.c
+ */
+#include "postgres.h"
+
+#include "access/gist.h"
+#include "access/gist_private.h"
+#include "access/htup.h"
+#include "access/relation.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_am_d.h"
+#include "funcapi.h"
+#include "miscadmin.h"
+#include "pageinspect.h"
+#include "storage/itemptr.h"
+#include "utils/array.h"
+#include "utils/builtins.h"
+#include "utils/pg_lsn.h"
+#include "utils/lsyscache.h"
+#include "utils/rel.h"
+#include "utils/ruleutils.h"
+#include "utils/varlena.h"
+
+PG_FUNCTION_INFO_V1(gist_page_opaque_info);
+PG_FUNCTION_INFO_V1(gist_page_items);
+PG_FUNCTION_INFO_V1(gist_page_items_bytea);
+
+#define IS_GIST(r) ((r)->rd_rel->relam == GIST_AM_OID)
+
+#define ItemPointerGetDatum(X)	 PointerGetDatum(X)
+
+
+static Page verify_gist_page(bytea *raw_page);
+
+/*
+ * Verify that the given bytea contains a GIST page or die in the attempt.
+ * A pointer to the page is returned.
+ */
+static Page
+verify_gist_page(bytea *raw_page)
+{
+	Page		page = get_page_from_raw(raw_page);
+	GISTPageOpaque opaq;
+
+	if (PageIsNew(page))
+		return page;
+
+	/* verify the special space has the expected size */
+	if (PageGetSpecialSize(page) != MAXALIGN(sizeof(GISTPageOpaqueData)))
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("input page is not a valid %s page", "GiST"),
+				 errdetail("Expected special size %d, got %d.",
+						   (int) MAXALIGN(sizeof(GISTPageOpaqueData)),
+						   (int) PageGetSpecialSize(page))));
+
+	opaq = GistPageGetOpaque(page);
+	if (opaq->gist_page_id != GIST_PAGE_ID)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("input page is not a valid %s page", "GiST"),
+				 errdetail("Expected %08x, got %08x.",
+						   GIST_PAGE_ID,
+						   opaq->gist_page_id)));
+
+	return page;
+}
+
+Datum
+gist_page_opaque_info(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	TupleDesc	tupdesc;
+	Page		page;
+	HeapTuple	resultTuple;
+	Datum		values[4];
+	bool		nulls[4];
+	Datum		flags[16];
+	int			nflags = 0;
+	uint16		flagbits;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	page = verify_gist_page(raw_page);
+
+	if (PageIsNew(page))
+		PG_RETURN_NULL();
+
+	/* Build a tuple descriptor for our result type */
+	if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
+		elog(ERROR, "return type must be a row type");
+
+	/* Convert the flags bitmask to an array of human-readable names */
+	flagbits = GistPageGetOpaque(page)->flags;
+	if (flagbits & F_LEAF)
+		flags[nflags++] = CStringGetTextDatum("leaf");
+	if (flagbits & F_DELETED)
+		flags[nflags++] = CStringGetTextDatum("deleted");
+	if (flagbits & F_TUPLES_DELETED)
+		flags[nflags++] = CStringGetTextDatum("tuples_deleted");
+	if (flagbits & F_FOLLOW_RIGHT)
+		flags[nflags++] = CStringGetTextDatum("follow_right");
+	if (flagbits & F_HAS_GARBAGE)
+		flags[nflags++] = CStringGetTextDatum("has_garbage");
+	flagbits &= ~(F_LEAF | F_DELETED | F_TUPLES_DELETED | F_FOLLOW_RIGHT | F_HAS_GARBAGE);
+	if (flagbits)
+	{
+		/* any flags we don't recognize are printed in hex */
+		flags[nflags++] = DirectFunctionCall1(to_hex32, Int32GetDatum(flagbits));
+	}
+
+	memset(nulls, 0, sizeof(nulls));
+
+	values[0] = LSNGetDatum(PageGetLSN(page));
+	values[1] = LSNGetDatum(GistPageGetNSN(page));
+	values[2] = Int64GetDatum(GistPageGetOpaque(page)->rightlink);
+	values[3] = PointerGetDatum(construct_array(flags, nflags,
+												TEXTOID,
+												-1, false, TYPALIGN_INT));
+
+	/* Build and return the result tuple. */
+	resultTuple = heap_form_tuple(tupdesc, values, nulls);
+
+	return HeapTupleGetDatum(resultTuple);
+}
+
+Datum
+gist_page_items_bytea(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	Page		page;
+	OffsetNumber offset;
+	OffsetNumber maxoff = InvalidOffsetNumber;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	InitMaterializedSRF(fcinfo, 0);
+
+	page = verify_gist_page(raw_page);
+
+	if (PageIsNew(page))
+		PG_RETURN_NULL();
+
+	/* Avoid bogus PageGetMaxOffsetNumber() call with deleted pages */
+	if (GistPageIsDeleted(page))
+		elog(NOTICE, "page is deleted");
+	else
+		maxoff = PageGetMaxOffsetNumber(page);
+
+	for (offset = FirstOffsetNumber;
+		 offset <= maxoff;
+		 offset++)
+	{
+		Datum		values[5];
+		bool		nulls[5];
+		ItemId		id;
+		IndexTuple	itup;
+		bytea	   *tuple_bytea;
+		int			tuple_len;
+
+		id = PageGetItemId(page, offset);
+
+		if (!ItemIdIsValid(id))
+			elog(ERROR, "invalid ItemId");
+
+		itup = (IndexTuple) PageGetItem(page, id);
+		tuple_len = IndexTupleSize(itup);
+
+		memset(nulls, 0, sizeof(nulls));
+
+		values[0] = DatumGetInt16(offset);
+		values[1] = ItemPointerGetDatum(&itup->t_tid);
+		values[2] = Int32GetDatum((int) IndexTupleSize(itup));
+
+		tuple_bytea = (bytea *) palloc(tuple_len + VARHDRSZ);
+		SET_VARSIZE(tuple_bytea, tuple_len + VARHDRSZ);
+		memcpy(VARDATA(tuple_bytea), itup, tuple_len);
+		values[3] = BoolGetDatum(ItemIdIsDead(id));
+		values[4] = PointerGetDatum(tuple_bytea);
+
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
+	}
+
+	return (Datum) 0;
+}
+
+Datum
+gist_page_items(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	Oid			indexRelid = PG_GETARG_OID(1);
+	ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+	Relation	indexRel;
+	TupleDesc	tupdesc;
+	Page		page;
+	uint16		flagbits;
+	bits16		printflags = 0;
+	OffsetNumber offset;
+	OffsetNumber maxoff = InvalidOffsetNumber;
+	char	   *index_columns;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 errmsg("must be superuser to use raw page functions")));
+
+	InitMaterializedSRF(fcinfo, 0);
+
+	/* Open the relation */
+	indexRel = index_open(indexRelid, AccessShareLock);
+
+	if (!IS_GIST(indexRel))
+		ereport(ERROR,
+				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+				 errmsg("\"%s\" is not a %s index",
+						RelationGetRelationName(indexRel), "GiST")));
+
+	page = verify_gist_page(raw_page);
+
+	if (PageIsNew(page))
+	{
+		index_close(indexRel, AccessShareLock);
+		PG_RETURN_NULL();
+	}
+
+	flagbits = GistPageGetOpaque(page)->flags;
+
+	/*
+	 * Included attributes are added when dealing with leaf pages, discarded
+	 * for non-leaf pages as these include only data for key attributes.
+	 */
+	printflags |= RULE_INDEXDEF_PRETTY;
+	if (flagbits & F_LEAF)
+	{
+		tupdesc = RelationGetDescr(indexRel);
+	}
+	else
+	{
+		tupdesc = CreateTupleDescCopy(RelationGetDescr(indexRel));
+		tupdesc->natts = IndexRelationGetNumberOfKeyAttributes(indexRel);
+		printflags |= RULE_INDEXDEF_KEYS_ONLY;
+	}
+
+	index_columns = pg_get_indexdef_columns_extended(indexRelid,
+													 printflags);
+
+	/* Avoid bogus PageGetMaxOffsetNumber() call with deleted pages */
+	if (GistPageIsDeleted(page))
+		elog(NOTICE, "page is deleted");
+	else
+		maxoff = PageGetMaxOffsetNumber(page);
+
+	for (offset = FirstOffsetNumber;
+		 offset <= maxoff;
+		 offset++)
+	{
+		Datum		values[5];
+		bool		nulls[5];
+		ItemId		id;
+		IndexTuple	itup;
+		Datum		itup_values[INDEX_MAX_KEYS];
+		bool		itup_isnull[INDEX_MAX_KEYS];
+		StringInfoData buf;
+		int			i;
+
+		id = PageGetItemId(page, offset);
+
+		if (!ItemIdIsValid(id))
+			elog(ERROR, "invalid ItemId");
+
+		itup = (IndexTuple) PageGetItem(page, id);
+
+		index_deform_tuple(itup, tupdesc,
+						   itup_values, itup_isnull);
+
+		memset(nulls, 0, sizeof(nulls));
+
+		values[0] = DatumGetInt16(offset);
+		values[1] = ItemPointerGetDatum(&itup->t_tid);
+		values[2] = Int32GetDatum((int) IndexTupleSize(itup));
+		values[3] = BoolGetDatum(ItemIdIsDead(id));
+
+		if (index_columns)
+		{
+			initStringInfo(&buf);
+			appendStringInfo(&buf, "(%s)=(", index_columns);
+
+			/* Most of this is copied from record_out(). */
+			for (i = 0; i < tupdesc->natts; i++)
+			{
+				char	   *value;
+				char	   *tmp;
+				bool		nq = false;
+
+				if (itup_isnull[i])
+					value = "null";
+				else
+				{
+					Oid			foutoid;
+					bool		typisvarlena;
+					Oid			typoid;
+
+					typoid = tupdesc->attrs[i].atttypid;
+					getTypeOutputInfo(typoid, &foutoid, &typisvarlena);
+					value = OidOutputFunctionCall(foutoid, itup_values[i]);
+				}
+
+				if (i == IndexRelationGetNumberOfKeyAttributes(indexRel))
+					appendStringInfoString(&buf, ") INCLUDE (");
+				else if (i > 0)
+					appendStringInfoString(&buf, ", ");
+
+				/* Check whether we need double quotes for this value */
+				nq = (value[0] == '\0');	/* force quotes for empty string */
+				for (tmp = value; *tmp; tmp++)
+				{
+					char		ch = *tmp;
+
+					if (ch == '"' || ch == '\\' ||
+						ch == '(' || ch == ')' || ch == ',' ||
+						isspace((unsigned char) ch))
+					{
+						nq = true;
+						break;
+					}
+				}
+
+				/* And emit the string */
+				if (nq)
+					appendStringInfoCharMacro(&buf, '"');
+				for (tmp = value; *tmp; tmp++)
+				{
+					char		ch = *tmp;
+
+					if (ch == '"' || ch == '\\')
+						appendStringInfoCharMacro(&buf, ch);
+					appendStringInfoCharMacro(&buf, ch);
+				}
+				if (nq)
+					appendStringInfoCharMacro(&buf, '"');
+			}
+
+			appendStringInfoChar(&buf, ')');
+
+			values[4] = CStringGetTextDatum(buf.data);
+			nulls[4] = false;
+		}
+		else
+		{
+			values[4] = (Datum) 0;
+			nulls[4] = true;
+		}
+
+		tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
+	}
+
+	relation_close(indexRel, AccessShareLock);
+
+	return (Datum) 0;
+}