Help Center/GaussDB/Developer Guide(Distributed_V2.0-8.x)/System Catalogs and System Views/System Views/Segment-Page Storage/GS_SEG_SEGMENTS
Updated on 2025-08-19 GMT+08:00
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GS_SEG_SEGMENTS

GS_SEG_SEGMENTS displays information about segments in all tablespaces, including tables, indexes, TOAST, TOAST INDEX segments, and fsm fork and vm fork segments. Only an administrator can query the information.

Table 1 GS_SEG_SEGMENTS columns

Name

Type

Description

node_name

text

Node name.

schema_name

name

Namespace to which a segment belongs.

segment_name

name

Segment object name, which is obtained from pg_class and relname in pg_partition.

partition_name

name

Partition name of the segment object; NULL if the segment object is not partitioned. Source: pg_partition.relname.

forknum

integer

Fork type of a segment object. Value range:

  • 0: main fork.
  • 1: FSM fork.
  • 2: VM fork.

segment_type

text

Segment object type. Value range:

  • table: segment-page ordinary table.
  • table partition: segment-page partitioned table (main table and child table) and segment-page level-2 partitioned table (level-1 partitioned table).
  • table subpartition: segment-page level-2 partitioned table (top node table and level-2 partitioned table).
  • index: index of a segment-page ordinary table.
  • index partition: index of a segment-page partitioned table or level-2 partitioned table.
  • global partition index: global index for segment-page partitioned tables and level-2 partitioned tables.
  • toast: segment-page TOAST table.
  • toast index: index of a segment-page TOAST table.

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.
  • 2048 to 6143 indicate the bucket nodes of a range bucket table.

head_block_id

bigint

Page number of the segment header.

contents

text

Storage content of a data file. Value range:
  • permanent: permanent.
  • unlogged: no log.
  • temporary: global temporary.
  • temporary2: local temporary.

table_name

name

Name of the base table to which a segment belongs.

blocks

bigint

Number of logical pages of a segment.

total_blocks

bigint

Number of physical pages of a segment.

extents

integer

Number of logical extents of a segment.

total_extents

integer

Number of physical extents of a segment.

head_lsn

text

Segment header LSN.

level0_slots

bigint[]

Level-0 slot array of segment extent mapping.

level1_slots

bigint[]

Level-1 slot array of segment extent mapping.

fork_head

bigint[]

Fork head array of a segment.