postgresql/contrib/pageinspect/fsmfuncs.c
Heikki Linnakangas 15c121b3ed 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.
2008-09-30 10:52:14 +00:00

62 lines
1.7 KiB
C

/*-------------------------------------------------------------------------
*
* 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));
}