System Catalogs / System views
pg_aios
Read the PG 18 manualThe pg_aios view lists all Asynchronous I/O handles that are currently in-use.
Reading PG 18current·documented in 3 of 24 versions, 18 to 20
- Kind
- System views
- Columns in this snapshot
- 15
- Definition source
- English manual
- Metadata snapshot
- 18.6
Columns 15
As listed in the PostgreSQL 18 manual.
| Column | Type | Description / reference |
|---|---|---|
pid | int4 | Process ID of the server process that is issuing this I/O. |
io_id | int4 | Identifier of the I/O handle. Handles are reused once the I/O completed (or if the handle is released before I/O is started). On reuse pg_aios.io_generation is incremented. |
io_generation | int8 | Generation of the I/O handle. |
state | text | State of the I/O handle: HANDED_OUT, referenced by code but not yet used DEFINED, information necessary for execution is known STAGED, ready for execution SUBMITTED, submitted for execution COMPLETED_IO, finished, but result has not yet been processed COMPLETED_SHARED, shared completion processing completed COMPLETED_LOCAL, backend local completion processing completed |
operation | text | Operation performed using the I/O handle: invalid, not yet known readv, a vectored read writev, a vectored write |
off | int8 | Offset of the I/O operation. |
length | int8 | Length of the I/O operation. |
target | text | What kind of object is the I/O targeting: smgr, I/O on relations |
handle_data_len | int2 | Length of the data associated with the I/O operation. For I/O to/from shared_buffers and temp_buffers, this indicates the number of buffers the I/O is operating on. |
raw_result | int4 | Low-level result of the I/O operation, or NULL if the operation has not yet completed. |
result | text | High-level result of the I/O operation: UNKNOWN means that the result of the operation is not yet known. OK means the I/O completed successfully. PARTIAL means that the I/O completed without error, but did not process all data. Commonly callers will need to retry and perform the remainder of the work in a separate I/O. WARNING means that the I/O completed without error, but that execution of the IO triggered a warning. E.g. when encountering a corrupted buffer with zero_damaged_pages enabled. ERROR means the I/O failed with an error. |
target_desc | text | Description of what the I/O operation is targeting. |
f_sync | bool | Flag indicating whether the I/O is executed synchronously. |
f_localmem | bool | Flag indicating whether the I/O references process local memory. |
f_buffered | bool | Flag indicating whether the I/O is buffered I/O. |
Column history across versions
Version history 1
- 17 → 18 added
Definition snapshot: english-manuals:8aee55a862794c52c55af2fece1… · English manual source