pg_appendonly
The pg_appendonly table contains information about the storage options and other characteristics of append-only tables.
Table 1. pg_catalog.pg_appendonly
| column | type | references | description |
|---|---|---|---|
relid |
oid | The table object identifier (OID) of the compressed table. | |
compresslevel |
smallint | The compression level, with increasing compression ratio. If the gzip or zlib compression type is specified, valid values are 1-9. |
|
majorversion |
smallint | The major version number of the pg_appendonly table. |
|
minorversion |
smallint | The minor version number of the pg_appendonly table. |
|
checksum |
boolean | A checksum value that is stored to compare the state of a block of data at compression time and at scan time to ensure data integrity. | |
compresstype |
text | Type of compression used on append-only and parquet tables. zlib, snappy, and gzip compression types are supported. |
|
columnstore |
boolean | 0 for row-oriented storage. |
|
segrelid |
oid | Table on-disk segment file id. | |
segidxid |
oid | Index on-disk segment file id. | |
blkdirrelid |
oid | Block used for on-disk column-oriented table file. | |
blkdiridxid |
oid | Block used for on-disk column-oriented index file. | |
version |
integer | Version of MemTuples and block layout for this table. | |
pagesize |
integer | The max page size of this relation. Only valid for Parquet tables; otherwise, the value is 0. | |
splitsize |
integer | Size of a split. Default value is 64M, which is controlled by server configuration parameter appendonly_split_write_size_mb. |