__gp_aocsseg_history(regclass)
This function returns metadata information contained in a column-oriented append-optimized table's on-disk segment file. Each row describes a segment for a column in the table. The data is complex, but users with a deep understanding of the system may find it useful for debugging.
The input argument is the name or the OID of a column-oriented append-optimized table.
| Column | Description |
|---|---|
gp_tid |
The ID of the tuple |
gp_xmin |
The earliest transaction |
gp_xmin_status |
The status of the |
gp_xmin_distrib_id |
Distribution ID of the |
gp_xmax |
The latest transaction |
gp_xmax_status |
The status of the |
gp_xmax_distrib_id |
Distribution ID of the |
gp_command_id |
ID of the command operating on the tuple |
gp_infomask |
A bitmap containing state information |
gp_update_tid |
The ID of the newer tuple if the row is updated |
gp_visibility |
The tuple visibility status |
segno |
The segment number in the segment file |
column_num |
The column number |
physical_segno |
The segment containing data for the column |
tupcount |
The total number of tuples in the segment |
eof |
The effective end of file for the segment |
eof_uncompressed |
The end of file for the segment if the data were uncompressed |
modcount |
A count of the data modification operations |
formatversion |
The storage format version of the append-only segment file |
state |
The state of the segment |