数据仓库服务 GAUSSDB(DWS)-统计信息函数:pg_xlogdump (tablename)

时间：2024-07-08 10:36:05

pg_xlogdump (tablename)

描述：在CN或者DN上执行，根据表名解析xlog文件并过滤。该函数仅8.3.0及以上集群版本支持。

返回值类型：record

返回信息如下：

名称	类型	描述
node_name	text	节点名称。
start_lsn	text	设定的起始LSN。
end_lsn	text	设定的终止LSN。
startlsn	text	xlog起始lsn。
endlsn	text	xlog终止lsn。
prelsn	text	前一条xlog起始lsn。
xid	xid	xlog事务id号。
datalen	int4	xlog数据长度，单位为byte。
totallen	int4	xlog长度，单位为byte。
type	text	xlog类型。
desc	text	xlog内容。
blkref	text	xlog关联的relfilenode。

由于不同xlog类型xlogdescribe字段的长度不一致，pg_xlogdump()函数会对该字段进行裁剪，仅保留前64个字节。
可以找到目标xlog后结合pg_xlog_display_one_lsn()函数查看完整xlog内容。

示例：

  
   
     
     
       SELECT * FROM pg_xlogdump(pg_class);
 node_name | startlsn  |  endlsn   |  prelsn   | xlog_tid | datalen | totallen | xlogtype |  xlogdescribe   |                      blkref
-----------+-----------+-----------+-----------+----------+---------+----------+----------+-----------------+---------------------------------------------------
 datanode1 | 0/2DFC660 | 0/2DFE1D0 | 0/2DFA610 |        0 |       2 |     7000 | Heap     | inplace: off 17 | blkrel #0: rel 1663/16324/15920, fork main, blk 2
 datanode1 | 0/2E02270 | 0/2E02D88 | 0/2E00220 |        0 |       2 |     2840 | Heap     | inplace: off 2  | blkrel #0: rel 1663/16324/15920, fork main, blk 0
 datanode1 | 0/2E06E60 | 0/2E06F68 | 0/2E06E28 |        0 |       2 |      264 | Heap     | inplace: off 10 | blkrel #0: rel 1663/16324/15920, fork main, blk 0
 datanode1 | 0/2E0FC08 | 0/2E0FD10 | 0/2E0EBB8 |        0 |       2 |      264 | Heap     | inplace: off 13 | blkrel #0: rel 1663/16324/15920, fork main, blk 0
 datanode1 | 0/2E12960 | 0/2E12A68 | 0/2E11960 |        0 |       2 |      264 | Heap     | inplace: off 15 | blkrel #0: rel 1663/16324/15920, fork main, blk 0
 datanode1 | 0/2E12C88 | 0/2E12D90 | 0/2E12B78 |        0 |       2 |      264 | Heap     | inplace: off 17 | blkrel #0: rel 1663/16324/15920, fork main, blk 0
 datanode1 | 0/2E13FF8 | 0/2E14118 | 0/2E13110 |        0 |       2 |      264 | Heap     | inplace: off 18 | blkrel #0: rel 1663/16324/15920, fork main, blk 0
 datanode1 | 0/2E169F8 | 0/2E185E0 | 0/2E169B0 |        0 |       2 |     7120 | Heap     | inplace: off 1  | blkrel #0: rel 1663/16324/15920, fork main, blk 1
 datanode1 | 0/2E188B8 | 0/2E189D0 | 0/2E185E0 |        0 |       2 |      280 | Heap     | inplace: off 2  | blkrel #0: rel 1663/16324/15920, fork main, blk 1
 datanode1 | 0/2E18BF8 | 0/2E18CE0 | 0/2E189D0 |        0 |       2 |      232 | Heap     | inplace: off 28 | blkrel #0: rel 1663/16324/15920, fork main, blk 1
 datanode1 | 0/2E18E80 | 0/2E18F88 | 0/2E18DC0 |        0 |       2 |      264 | Heap     | inplace: off 4  | blkrel #0: rel 1663/16324/15920, fork main, blk 1
 datanode1 | 0/2E19160 | 0/2E19268 | 0/2E19088 |        0 |       2 |      264 | Heap     | inplace: off 5  | blkrel #0: rel 1663/16324/15920, fork main, blk 1
 datanode1 | 0/2E19460 | 0/2E1B1D0 | 0/2E19388 |        0 |       2 |     7508 | Heap     | inplace: off 16 | blkrel #0: rel 1663/16324/15920, fork main, blk 6
 datanode1 | 0/2E1B1D0 | 0/2E1B2E8 | 0/2E19460 |        0 |       2 |      280 | Heap     | inplace: off 18 | blkrel #0: rel 1663/16324/15920, fork main, blk 6
 datanode1 | 0/2E1B2E8 | 0/2E1B3D0 | 0/2E1B1D0 |        0 |       2 |      232 | Heap     | inplace: off 30 | blkrel #0: rel 1663/16324/15920, fork main, blk 1
(15 rows)

      

    

  
 