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On machines with MAXALIGN = 8, the payload of a bytea is not maxaligned,
since it will start 4 bytes into a palloc'd value. On alignment-picky
hardware, this will cause failures in accesses to 8-byte-wide values
within the page. We already encountered this problem when we introduced
GIN index inspection functions, and fixed it in commit 84ad68d64
. Make
use of the same function for hash indexes.
A small difficulty is that up to now contrib/pageinspect has not shared
any functions at all across files. To support that, introduce a common
header file "pageinspect.h" for the module.
Also, move get_page_from_raw() out of ginfuncs.c, where it didn't
especially belong, and put it in rawpage.c which seems a more natural home.
Per buildfarm.
Discussion: https://postgr.es/m/17311.1486134714@sss.pgh.pa.us
61 lines
1.5 KiB
C
61 lines
1.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* fsmfuncs.c
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* Functions to investigate FSM pages
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*
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* These functions are restricted to superusers for the fear of introducing
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* security holes if the input checking isn't as water-tight as it should.
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* You'd need to be superuser to obtain a raw page image anyway, so
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* there's hardly any use case for using these without superuser-rights
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* anyway.
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*
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* Copyright (c) 2007-2017, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/pageinspect/fsmfuncs.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "pageinspect.h"
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#include "funcapi.h"
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#include "lib/stringinfo.h"
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#include "miscadmin.h"
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#include "storage/fsm_internals.h"
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#include "utils/builtins.h"
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/*
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* Dumps the contents of a FSM page.
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*/
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PG_FUNCTION_INFO_V1(fsm_page_contents);
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Datum
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fsm_page_contents(PG_FUNCTION_ARGS)
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{
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bytea *raw_page = PG_GETARG_BYTEA_P(0);
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StringInfoData sinfo;
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FSMPage fsmpage;
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int i;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("must be superuser to use raw page functions"))));
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fsmpage = (FSMPage) PageGetContents(VARDATA(raw_page));
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initStringInfo(&sinfo);
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for (i = 0; i < NodesPerPage; i++)
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{
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if (fsmpage->fp_nodes[i] != 0)
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appendStringInfo(&sinfo, "%d: %d\n", i, fsmpage->fp_nodes[i]);
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}
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appendStringInfo(&sinfo, "fp_next_slot: %d\n", fsmpage->fp_next_slot);
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PG_RETURN_TEXT_P(cstring_to_text_with_len(sinfo.data, sinfo.len));
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}
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