git.postgresql.org Git - postgresql.git/commitdiff

diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out

index 08599af774d0157c78d2e5593ef87dc4dea5ea52..8e15947a8187326351b2684aae3b362e319660d2 100644 (file)

--- a/contrib/pageinspect/expected/page.out

+++ b/contrib/pageinspect/expected/page.out

8192 | 4

(1 row)

+SELECT page_checksum(get_raw_page('test1', 0), 0) IS NOT NULL AS silly_checksum_test;

+ silly_checksum_test

+---------------------

+ t

+(1 row)

+

SELECT tuple_data_split('test1'::regclass, t_data, t_infomask, t_infomask2, t_bits)

FROM heap_page_items(get_raw_page('test1', 0));

tuple_data_split

diff --git a/contrib/pageinspect/pageinspect--1.5--1.6.sql b/contrib/pageinspect/pageinspect--1.5--1.6.sql

index ac3956882c94c64c7aae36b8c75d9167234b1ac3..6ac2a8011d80a1af6e178029685adcdf634d3be2 100644 (file)

--- a/contrib/pageinspect/pageinspect--1.5--1.6.sql

+++ b/contrib/pageinspect/pageinspect--1.5--1.6.sql

OUT mapp int8[])

AS 'MODULE_PATHNAME', 'hash_metapage_info'

LANGUAGE C STRICT PARALLEL SAFE;

+

+--

+-- page_checksum()

+--

+CREATE FUNCTION page_checksum(IN page bytea, IN blkno int4)

+RETURNS smallint

+AS 'MODULE_PATHNAME', 'page_checksum'

+LANGUAGE C STRICT PARALLEL SAFE;

diff --git a/contrib/pageinspect/rawpage.c b/contrib/pageinspect/rawpage.c

index a5def917511cd5ce78dc2c92ad6ab0aeb3cdf298..631e435a939c2a56c30ea3d7ac28bd623e69c681 100644 (file)

--- a/contrib/pageinspect/rawpage.c

+++ b/contrib/pageinspect/rawpage.c

#include "funcapi.h"

#include "miscadmin.h"

#include "storage/bufmgr.h"

+#include "storage/checksum.h"

#include "utils/builtins.h"

#include "utils/pg_lsn.h"

#include "utils/rel.h"

PG_RETURN_DATUM(result);

}

+

+/*

+ * page_checksum

+ *

+ * Compute checksum of a raw page

+ */

+

+PG_FUNCTION_INFO_V1(page_checksum);

+

+Datum

+page_checksum(PG_FUNCTION_ARGS)

+{

+ bytea *raw_page = PG_GETARG_BYTEA_P(0);

+ uint32 blkno = PG_GETARG_INT32(1);

+ int raw_page_size;

+ PageHeader page;

+

+ if (!superuser())

+ ereport(ERROR,

+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),

+ (errmsg("must be superuser to use raw page functions"))));

+

+ raw_page_size = VARSIZE(raw_page) - VARHDRSZ;

+

+ /*

+ * Check that the supplied page is of the right size.

+ */

+ if (raw_page_size != BLCKSZ)

+ ereport(ERROR,

+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),

+ errmsg("incorrect size of input page (%d bytes)", raw_page_size)));

+

+ page = (PageHeader) VARDATA(raw_page);

+

+ PG_RETURN_INT16(pg_checksum_page((char *)page, blkno));

+}

diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql

index 53e9f8022d437772840a65bdd8d7237a597fb9b0..493ca9b211d38db0105dbca6a3f28361c382a224 100644 (file)

--- a/contrib/pageinspect/sql/page.sql

+++ b/contrib/pageinspect/sql/page.sql

SELECT pagesize, version FROM page_header(get_raw_page('test1', 0));

+SELECT page_checksum(get_raw_page('test1', 0), 0) IS NOT NULL AS silly_checksum_test;

+

SELECT tuple_data_split('test1'::regclass, t_data, t_infomask, t_infomask2, t_bits)

FROM heap_page_items(get_raw_page('test1', 0));

diff --git a/doc/src/sgml/pageinspect.sgml b/doc/src/sgml/pageinspect.sgml

index 5e6712f9cdee7c4943a64157b97bdc9423c20df9..9f41bb21eb9f22006cff40d60913655423ecc6bb 100644 (file)

--- a/doc/src/sgml/pageinspect.sgml

+++ b/doc/src/sgml/pageinspect.sgml

test=# SELECT * FROM page_header(get_raw_page('pg_class', 0));

lsn | checksum | flags | lower | upper | special | pagesize | version | prune_xid

-----------+----------+--------+-------+-------+---------+----------+---------+-----------

- 0/24A1B50 | 1 | 1 | 232 | 368 | 8192 | 8192 | 4 | 0

+ 0/24A1B50 | 0 | 1 | 232 | 368 | 8192 | 8192 | 4 | 0

</screen>

The returned columns correspond to the fields in the

<structname>PageHeaderData</> struct.

See <filename>src/include/storage/bufpage.h</> for details.

- </para>

+ </para>

+

+ <para>

+ The <structfield>checksum</structfield> field is the checksum stored in

+ the page, which might be incorrect if the page is somehow corrupted. If

+ data checksums are not enabled for this instance, then the value stored

+ is meaningless.

+ </para>

+ </listitem>

+ </varlistentry>

+

+ <varlistentry>

+ <term>

+ <function>page_checksum(page bytea, blkno int4) returns smallint</function>

+ <indexterm>

+ <primary>page_checksum</primary>

+ </indexterm>

+ </term>

+

+ <listitem>

+ <para>

+ <function>page_checksum</function> computes the checksum for the page, as if

+ it was located at the given block.

+ </para>

+

+ <para>

+ A page image obtained with <function>get_raw_page</function> should be

+ passed as argument. For example:

+<screen>

+test=# SELECT page_checksum(get_raw_page('pg_class', 0), 0);

+ page_checksum

+---------------

+ 13443

+</screen>

+ Note that the checksum depends on the block number, so matching block

+ numbers should be passed (except when doing esoteric debugging).

+ </para>

+

+ <para>

+ The checksum computed with this function can be compared with

+ the <structfield>checksum</structfield> result field of the

+ function <function>page_header</function>. If data checksums are

+ enabled for this instance, then the two values should be equal.

+ </para>

</listitem>

</varlistentry>