Rewrite the FSM. Instead of relying on a fixed-size shared memory segment, the

free space information is stored in a dedicated FSM relation fork, with each
relation (except for hash indexes; they don't use FSM).

This eliminates the max_fsm_relations and max_fsm_pages GUC options; remove any
trace of them from the backend, initdb, and documentation.

Rewrite contrib/pg_freespacemap to match the new FSM implementation. Also
introduce a new variant of the get_raw_page(regclass, int4, int4) function in
contrib/pageinspect that let's you to return pages from any relation fork, and
a new fsm_page_contents() function to inspect the new FSM pages.

1 files changed, 61 insertions, 0 deletions

diff --git a/contrib/pageinspect/fsmfuncs.c b/contrib/pageinspect/fsmfuncs.c
new file mode 100644
index 0000000000..fb522e5ff5
--- /dev/null
+++ b/contrib/pageinspect/fsmfuncs.c
@@ -0,0 +1,61 @@
+/*-------------------------------------------------------------------------
+ *
+ * fsmfuncs.c
+ *	  Functions to investigate FSM pages
+ *
+ * These functions are restricted to superusers for the fear of introducing
+ * security holes if the input checking isn't as water-tight as it should.
+ * You'd need to be superuser to obtain a raw page image anyway, so
+ * there's hardly any use case for using these without superuser-rights
+ * anyway.
+ *
+ * Copyright (c) 2007-2008, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *	  $PostgreSQL: pgsql/contrib/pageinspect/fsmfuncs.c,v 1.1 2008/09/30 10:52:09 heikki Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+#include "lib/stringinfo.h"
+#include "storage/fsm_internals.h"
+#include "utils/builtins.h"
+#include "miscadmin.h"
+#include "funcapi.h"
+
+Datum fsm_page_contents(PG_FUNCTION_ARGS);
+
+/*
+ * Dumps the contents of a FSM page.
+ */
+PG_FUNCTION_INFO_V1(fsm_page_contents);
+
+Datum
+fsm_page_contents(PG_FUNCTION_ARGS)
+{
+	bytea	   *raw_page = PG_GETARG_BYTEA_P(0);
+	int			raw_page_size;
+	StringInfoData sinfo;
+	FSMPage		fsmpage;
+	int			i;
+
+	if (!superuser())
+		ereport(ERROR,
+				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+				 (errmsg("must be superuser to use raw page functions"))));
+
+	raw_page_size = VARSIZE(raw_page) - VARHDRSZ;
+	fsmpage = (FSMPage) PageGetContents(VARDATA(raw_page));
+
+	initStringInfo(&sinfo);
+
+	for(i=0; i < NodesPerPage; i++)
+	{
+		if (fsmpage->fp_nodes[i] != 0)
+			appendStringInfo(&sinfo, "%d: %d\n", i, fsmpage->fp_nodes[i]);
+	}
+	appendStringInfo(&sinfo, "fp_next_slot: %d\n", fsmpage->fp_next_slot);
+
+	PG_RETURN_TEXT_P(cstring_to_text(sinfo.data));
+}