ClickHouse/docs/en/operations/system-tables/errors.md
Azat Khuzhin 7c07b43597 Convert system.errors.stack_trace from String into Array(UInt64)
This should decrease overhead for the errors collecting.
2021-03-24 06:52:48 +03:00

37 lines
1.6 KiB
Markdown

# system.errors {#system_tables-errors}
Contains error codes with the number of times they have been triggered.
Columns:
- `name` ([String](../../sql-reference/data-types/string.md)) — name of the error (`errorCodeToName`).
- `code` ([Int32](../../sql-reference/data-types/int-uint.md)) — code number of the error.
- `value` ([UInt64](../../sql-reference/data-types/int-uint.md)) — the number of times this error has been happened.
- `last_error_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — time when the last error happened.
- `last_error_message` ([String](../../sql-reference/data-types/string.md)) — message for the last error.
- `last_error_trace` ([Array(UInt64)](../../sql-reference/data-types/array.md)) — A [stack trace](https://en.wikipedia.org/wiki/Stack_trace) which represents a list of physical addresses where the called methods are stored.
- `remote` ([UInt8](../../sql-reference/data-types/int-uint.md)) — remote exception (i.e. received during one of the distributed query).
**Example**
``` sql
SELECT name, code, value
FROM system.errors
WHERE value > 0
ORDER BY code ASC
LIMIT 1
┌─name─────────────┬─code─┬─value─┐
│ CANNOT_OPEN_FILE │ 76 │ 1 │
└──────────────────┴──────┴───────┘
```
``` sql
WITH arrayMap(x -> demangle(addressToSymbol(x)), last_error_trace) AS all
SELECT name, arrayStringConcat(all, '\n') AS res
FROM system.errors
LIMIT 1
SETTINGS allow_introspection_functions=1\G
```