PGFILEDESC = "pg_walinspect - functions to inspect contents of PostgreSQL Write-Ahead Log"
EXTENSION = pg_walinspect
-DATA = pg_walinspect--1.0.sql
+DATA = pg_walinspect--1.0.sql pg_walinspect--1.0--1.1.sql
REGRESS = pg_walinspect
SELECT pg_current_wal_lsn() AS wal_lsn1 \gset
INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
SELECT pg_current_wal_lsn() AS wal_lsn2 \gset
-INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
+INSERT INTO sample_tbl SELECT * FROM generate_series(3, 4);
-- ===================================================================
-- Tests for input validation
-- ===================================================================
t
(1 row)
+-- ===================================================================
+-- Tests to get full page image (FPI) from WAL record
+-- ===================================================================
+SELECT pg_current_wal_lsn() AS wal_lsn3 \gset
+-- Force FPI on the next update.
+CHECKPOINT;
+-- Update table to generate an FPI.
+UPDATE sample_tbl SET col1 = col1 * 100 WHERE col1 = 1;
+SELECT pg_current_wal_lsn() AS wal_lsn4 \gset
+-- Check if we get FPI from WAL record.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_fpi_info(:'wal_lsn3', :'wal_lsn4')
+ WHERE relfilenode = :'sample_tbl_oid';
+ ok
+----
+ t
+(1 row)
+
-- ===================================================================
-- Tests for permissions
-- ===================================================================
f
(1 row)
+SELECT has_function_privilege('regress_pg_walinspect',
+ 'pg_get_wal_fpi_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- no
+ has_function_privilege
+------------------------
+ f
+(1 row)
+
-- Functions accessible by users with role pg_read_server_files
GRANT pg_read_server_files TO regress_pg_walinspect;
SELECT has_function_privilege('regress_pg_walinspect',
t
(1 row)
+SELECT has_function_privilege('regress_pg_walinspect',
+ 'pg_get_wal_fpi_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- yes
+ has_function_privilege
+------------------------
+ t
+(1 row)
+
REVOKE pg_read_server_files FROM regress_pg_walinspect;
-- Superuser can grant execute to other users
GRANT EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn)
TO regress_pg_walinspect;
GRANT EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean)
TO regress_pg_walinspect;
+GRANT EXECUTE ON FUNCTION pg_get_wal_fpi_info(pg_lsn, pg_lsn)
+ TO regress_pg_walinspect;
SELECT has_function_privilege('regress_pg_walinspect',
'pg_get_wal_record_info(pg_lsn)', 'EXECUTE'); -- yes
has_function_privilege
t
(1 row)
+SELECT has_function_privilege('regress_pg_walinspect',
+ 'pg_get_wal_fpi_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- yes
+ has_function_privilege
+------------------------
+ t
+(1 row)
+
REVOKE EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn)
FROM regress_pg_walinspect;
REVOKE EXECUTE ON FUNCTION pg_get_wal_records_info(pg_lsn, pg_lsn)
FROM regress_pg_walinspect;
REVOKE EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean)
FROM regress_pg_walinspect;
+REVOKE EXECUTE ON FUNCTION pg_get_wal_fpi_info(pg_lsn, pg_lsn)
+ FROM regress_pg_walinspect;
-- ===================================================================
-- Clean up
-- ===================================================================
install_data(
'pg_walinspect.control',
'pg_walinspect--1.0.sql',
+ 'pg_walinspect--1.0--1.1.sql',
kwargs: contrib_data_args,
)
--- /dev/null
+/* contrib/pg_walinspect/pg_walinspect--1.0--1.1.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pg_walinspect UPDATE TO '1.1'" to load this file. \quit
+
+--
+-- pg_get_wal_fpi_info()
+--
+CREATE FUNCTION pg_get_wal_fpi_info(IN start_lsn pg_lsn,
+ IN end_lsn pg_lsn,
+ OUT lsn pg_lsn,
+ OUT reltablespace oid,
+ OUT reldatabase oid,
+ OUT relfilenode oid,
+ OUT relblocknumber int8,
+ OUT forkname text,
+ OUT fpi bytea
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME', 'pg_get_wal_fpi_info'
+LANGUAGE C STRICT PARALLEL SAFE;
+
+REVOKE EXECUTE ON FUNCTION pg_get_wal_fpi_info(pg_lsn, pg_lsn) FROM PUBLIC;
+GRANT EXECUTE ON FUNCTION pg_get_wal_fpi_info(pg_lsn, pg_lsn) TO pg_read_server_files;
PG_MODULE_MAGIC;
+PG_FUNCTION_INFO_V1(pg_get_wal_fpi_info);
PG_FUNCTION_INFO_V1(pg_get_wal_record_info);
PG_FUNCTION_INFO_V1(pg_get_wal_records_info);
PG_FUNCTION_INFO_V1(pg_get_wal_records_info_till_end_of_wal);
Datum *values, bool *nulls, uint32 ncols);
static void GetWalStats(FunctionCallInfo fcinfo, XLogRecPtr start_lsn,
XLogRecPtr end_lsn, bool stats_per_record);
+static void GetWALFPIInfo(FunctionCallInfo fcinfo, XLogReaderState *record);
/*
* Check if the given LSN is in future. Also, return the LSN up to which the
Assert(i == ncols);
}
+
+/*
+ * Store a set of full page images from a single record.
+ */
+static void
+GetWALFPIInfo(FunctionCallInfo fcinfo, XLogReaderState *record)
+{
+#define PG_GET_WAL_FPI_INFO_COLS 7
+ int block_id;
+ ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
+
+ for (block_id = 0; block_id <= XLogRecMaxBlockId(record); block_id++)
+ {
+ PGAlignedBlock buf;
+ Page page;
+ bytea *raw_page;
+ BlockNumber blk;
+ RelFileLocator rnode;
+ ForkNumber fork;
+ Datum values[PG_GET_WAL_FPI_INFO_COLS] = {0};
+ bool nulls[PG_GET_WAL_FPI_INFO_COLS] = {0};
+ int i = 0;
+
+ if (!XLogRecHasBlockRef(record, block_id))
+ continue;
+
+ if (!XLogRecHasBlockImage(record, block_id))
+ continue;
+
+ page = (Page) buf.data;
+
+ if (!RestoreBlockImage(record, block_id, page))
+ ereport(ERROR,
+ (errcode(ERRCODE_INTERNAL_ERROR),
+ errmsg_internal("%s", record->errormsg_buf)));
+
+ /* Full page exists, so let's save it. */
+ (void) XLogRecGetBlockTagExtended(record, block_id,
+ &rnode, &fork, &blk, NULL);
+
+ values[i++] = LSNGetDatum(record->ReadRecPtr);
+ values[i++] = ObjectIdGetDatum(rnode.spcOid);
+ values[i++] = ObjectIdGetDatum(rnode.dbOid);
+ values[i++] = ObjectIdGetDatum(rnode.relNumber);
+ values[i++] = Int64GetDatum((int64) blk);
+
+ if (fork >= 0 && fork <= MAX_FORKNUM)
+ values[i++] = CStringGetTextDatum(forkNames[fork]);
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_INTERNAL_ERROR),
+ errmsg_internal("invalid fork number: %u", fork)));
+
+ /* Initialize bytea buffer to copy the FPI to. */
+ raw_page = (bytea *) palloc(BLCKSZ + VARHDRSZ);
+ SET_VARSIZE(raw_page, BLCKSZ + VARHDRSZ);
+
+ /* Take a verbatim copy of the FPI. */
+ memcpy(VARDATA(raw_page), page, BLCKSZ);
+
+ values[i++] = PointerGetDatum(raw_page);
+
+ Assert(i == PG_GET_WAL_FPI_INFO_COLS);
+
+ tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
+ values, nulls);
+ }
+
+#undef PG_GET_WAL_FPI_INFO_COLS
+}
+
+/*
+ * Get full page images with their relation information for all the WAL
+ * records between start and end LSNs. Decompression is applied to the
+ * blocks, if necessary.
+ *
+ * This function emits an error if a future start or end WAL LSN i.e. WAL LSN
+ * the database system doesn't know about is specified.
+ */
+Datum
+pg_get_wal_fpi_info(PG_FUNCTION_ARGS)
+{
+ XLogRecPtr start_lsn;
+ XLogRecPtr end_lsn;
+ XLogReaderState *xlogreader;
+
+ start_lsn = PG_GETARG_LSN(0);
+ end_lsn = PG_GETARG_LSN(1);
+
+ end_lsn = ValidateInputLSNs(false, start_lsn, end_lsn);
+
+ InitMaterializedSRF(fcinfo, 0);
+
+ xlogreader = InitXLogReaderState(start_lsn);
+
+ while (ReadNextXLogRecord(xlogreader) &&
+ xlogreader->EndRecPtr <= end_lsn)
+ {
+ GetWALFPIInfo(fcinfo, xlogreader);
+
+ CHECK_FOR_INTERRUPTS();
+ }
+
+ pfree(xlogreader->private_data);
+ XLogReaderFree(xlogreader);
+
+ PG_RETURN_VOID();
+}
+
/*
* Get WAL record info.
*
# pg_walinspect extension
comment = 'functions to inspect contents of PostgreSQL Write-Ahead Log'
-default_version = '1.0'
+default_version = '1.1'
module_pathname = '$libdir/pg_walinspect'
relocatable = true
SELECT pg_current_wal_lsn() AS wal_lsn2 \gset
-INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
+INSERT INTO sample_tbl SELECT * FROM generate_series(3, 4);
-- ===================================================================
-- Tests for input validation
SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', :'wal_lsn2')
WHERE resource_manager = 'Heap' AND record_type = 'INSERT';
+-- ===================================================================
+-- Tests to get full page image (FPI) from WAL record
+-- ===================================================================
+SELECT pg_current_wal_lsn() AS wal_lsn3 \gset
+
+-- Force FPI on the next update.
+CHECKPOINT;
+
+-- Update table to generate an FPI.
+UPDATE sample_tbl SET col1 = col1 * 100 WHERE col1 = 1;
+SELECT pg_current_wal_lsn() AS wal_lsn4 \gset
+
+-- Check if we get FPI from WAL record.
+SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_fpi_info(:'wal_lsn3', :'wal_lsn4')
+ WHERE relfilenode = :'sample_tbl_oid';
+
-- ===================================================================
-- Tests for permissions
-- ===================================================================
SELECT has_function_privilege('regress_pg_walinspect',
'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- no
+SELECT has_function_privilege('regress_pg_walinspect',
+ 'pg_get_wal_fpi_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- no
+
-- Functions accessible by users with role pg_read_server_files
GRANT pg_read_server_files TO regress_pg_walinspect;
SELECT has_function_privilege('regress_pg_walinspect',
'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+SELECT has_function_privilege('regress_pg_walinspect',
+ 'pg_get_wal_fpi_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- yes
+
REVOKE pg_read_server_files FROM regress_pg_walinspect;
-- Superuser can grant execute to other users
GRANT EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean)
TO regress_pg_walinspect;
+GRANT EXECUTE ON FUNCTION pg_get_wal_fpi_info(pg_lsn, pg_lsn)
+ TO regress_pg_walinspect;
+
SELECT has_function_privilege('regress_pg_walinspect',
'pg_get_wal_record_info(pg_lsn)', 'EXECUTE'); -- yes
SELECT has_function_privilege('regress_pg_walinspect',
'pg_get_wal_stats(pg_lsn, pg_lsn, boolean) ', 'EXECUTE'); -- yes
+SELECT has_function_privilege('regress_pg_walinspect',
+ 'pg_get_wal_fpi_info(pg_lsn, pg_lsn) ', 'EXECUTE'); -- yes
+
REVOKE EXECUTE ON FUNCTION pg_get_wal_record_info(pg_lsn)
FROM regress_pg_walinspect;
REVOKE EXECUTE ON FUNCTION pg_get_wal_stats(pg_lsn, pg_lsn, boolean)
FROM regress_pg_walinspect;
+REVOKE EXECUTE ON FUNCTION pg_get_wal_fpi_info(pg_lsn, pg_lsn)
+ FROM regress_pg_walinspect;
+
-- ===================================================================
-- Clean up
-- ===================================================================
</listitem>
</varlistentry>
+ <varlistentry>
+ <term>
+ <function>pg_get_wal_fpi_info(start_lsn pg_lsn, end_lsn pg_lsn) returns setof record</function>
+ </term>
+
+ <listitem>
+ <para>
+ Gets a copy of full page images as <type>bytea</type> values (after
+ applying decompression when necessary) and their information associated
+ with all the valid WAL records between
+ <replaceable>start_lsn</replaceable> and
+ <replaceable>end_lsn</replaceable>. Returns one row per full page image.
+ If <replaceable>start_lsn</replaceable> or
+ <replaceable>end_lsn</replaceable> are not yet available, the function
+ will raise an error. For example:
+<screen>
+postgres=# SELECT lsn, reltablespace, reldatabase, relfilenode, relblocknumber,
+ forkname, substring(fpi for 24) as fpi_trimmed
+ FROM pg_get_wal_fpi_info('0/1801690', '0/1825C60');
+-[ RECORD 1 ]--+---------------------------------------------------
+lsn | 0/1807E20
+reltablespace | 1663
+reldatabase | 5
+relfilenode | 16396
+relblocknumber | 43
+forkname | main
+fpi_trimmed | \x00000000b89e660100000000a003c0030020042000000000
+</screen>
+ </para>
+ </listitem>
+ </varlistentry>
+
</variablelist>
</sect2>
projects / users / gsingh / postgres.git / commitdiff