GLOBAL_GS_SEG_EXTENTS

GLOBAL_GS_SEG_EXTTENTS displays the extent information about all tablespaces on all nodes, which can only be executed on the CN. This view displays all extents of user segments, including segment heads, fork heads, and level-1 pages in file 1 and data extents in files 2 to 5. Only an administrator can query the information.

**Table 1** GLOBAL_GS_SEG_EXTTENTS columns
Name	Type	Description
node_name	text	Node name.
tablespace_name	name	Tablespace to which a segment object belongs.
bucketnode	integer	0 to 1023 indicate the bucket nodes of a hash bucket table. 1024 indicates the bucket node of a segment-page ordinary table. 1025 indicates the bucket node of a segment-page global temporary table. 1026 indicates the bucket node of a segment-page unlogged table. 1027 indicates the bucket node of a segment-page local temporary table.
head_block_id	bigint	Page number of the segment header.
extent_id	integer	Logical extent number.
file_id	integer	ID of the data file where the extent is located.
forknum	integer	Fork of a segment object. Value range: 0: main. 1: fsm. 2: vm.
block_id	bigint	Start page number in the data file where the extent is located.
blocks	integer	Extent size. The value can be 1, 8, 128, 1024, or 4096.
usage_type	text	Usage type of the extension. Value range: segment head: segment header. fork head: fork header. level1 page: level-1 page. data extent: data extents.