When the `input_format_csv_enum_as_number` setting is enabled:
When the `input_format_csv_enum_as_number` setting is enabled:
```sql
SETinput_format_csv_enum_as_number=1;
...
...
@@ -1841,7 +1841,7 @@ Default value: 0.
Enables or disables synchronous data insertion into a [Distributed](../../engines/table-engines/special/distributed.md#distributed) table.
By default, when inserting data into a `Distributed` table, the ClickHouse server sends data to cluster nodes in asynchronous mode. When `insert_distributed_sync=1`, the data is processed synchronously, and the `INSERT` operation succeeds only after all the data is saved on all shards (at least one replica for each shard if `internal_replication` is true).
By default, when inserting data into a `Distributed` table, the ClickHouse server sends data to cluster nodes in asynchronous mode. When `insert_distributed_sync=1`, the data is processed synchronously, and the `INSERT` operation succeeds only after all the data is saved on all shards (at least one replica for each shard if `internal_replication` is true).
- 1 - The query waits for all mutations to complete on the current server.
- 0 - Mutations execute asynchronously.
- 1 - The query waits for all mutations to complete on the current server.
- 2 - The query waits for all mutations to complete on all replicas (if they exist).
Default value: `0`.
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@@ -2137,11 +2137,11 @@ Default value: `0`.
## ttl_only_drop_parts {#ttl_only_drop_parts}
Enables or disables complete dropping of data parts where all rows are expired in [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
Enables or disables complete dropping of data parts where all rows are expired in [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md) tables.
When `ttl_only_drop_parts` is disabled (by default), the ClickHouse server only deletes expired rows according to their TTL.
When `ttl_only_drop_parts` is disabled (by default), the ClickHouse server only deletes expired rows according to their TTL.
When `ttl_only_drop_parts` is enabled, the ClickHouse server drops a whole part when all rows in it are expired.
When `ttl_only_drop_parts` is enabled, the ClickHouse server drops a whole part when all rows in it are expired.
Dropping whole parts instead of partial cleaning TTL-d rows allows having shorter `merge_with_ttl_timeout` times and lower impact on system performance.
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@@ -2152,14 +2152,14 @@ Possible values:
Default value: `0`.
**See Also**
**See Also**
-[CREATE TABLE query clauses and settings](../../engines/table-engines/mergetree-family/mergetree.md#mergetree-query-clauses)(`merge_with_ttl_timeout` setting)
Defines how many seconds a locking request waits before failing.
Defines how many seconds a locking request waits before failing.
Locking timeout is used to protect from deadlocks while executing read/write operations with tables. When the timeout expires and the locking request fails, the ClickHouse server throws an exception "Locking attempt timed out! Possible deadlock avoided. Client should retry." with error code `DEADLOCK_AVOIDED`.
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@@ -2179,11 +2179,11 @@ When the setting is enabled and the argument of `CAST` function is `Nullable`, t
Possible values:
- 0 — The `CAST` result has exactly the destination type specified.
- 1 — If the argument type is `Nullable`, the `CAST` result is transformed to `Nullable(DestinationDataType)`.
- 1 — If the argument type is `Nullable`, the `CAST` result is transformed to `Nullable(DestinationDataType)`.
Default value: `0`.
**Examples**
**Examples**
The following query results in the destination data type exactly:
Limits the width of value displayed in [Pretty](../../interfaces/formats.md#pretty) formats. If the value width exceeds the limit, the value is cut.
Limits the width of value displayed in [Pretty](../../interfaces/formats.md#pretty) formats. If the value width exceeds the limit, the value is cut.
Possible values:
- Positive integer.
- Positive integer.
- 0 — The value is cut completely.
Default value: `10000` symbols.
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@@ -2352,7 +2352,7 @@ Default value: `0`.
## persistent {#persistent}
Disables persistency for the [Set](../../engines/table-engines/special/set.md#set) and [Join](../../engines/table-engines/special/join.md#join) table engines.
Disables persistency for the [Set](../../engines/table-engines/special/set.md#set) and [Join](../../engines/table-engines/special/join.md#join) table engines.
Reduces the I/O overhead. Suitable for scenarios that pursue performance and do not require persistence.
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@@ -2426,7 +2426,7 @@ Result:
[
{"number":"0"},
{"number":"1"},
{"number":"2"}
{"number":"2"}
]
```
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@@ -2447,7 +2447,6 @@ Result:
{"number":"2"}
```
=======
## allow_nullable_key {#allow-nullable-key}
Allows using of the [Nullable](../../sql-reference/data-types/nullable.md#data_type-nullable)-typed values in a sorting and a primary key for [MergeTree](../../engines/table-engines/mergetree-family/mergetree.md#table_engines-mergetree) tables.
@@ -1252,7 +1251,7 @@ SELECT * FROM line_as_string;
## RawBLOB {#rawblob}
В этом формате все входные данные считываются в одно значение. Парсить можно только таблицу с одним полем типа [String](../sql-reference/data-types/string.md) или подобным ему.
В этом формате все входные данные считываются в одно значение. Парсить можно только таблицу с одним полем типа [String](../sql-reference/data-types/string.md) или подобным ему.
Результат выводится в бинарном виде без разделителей и экранирования. При выводе более одного значения формат неоднозначен и будет невозможно прочитать данные снова.
Ниже приведено сравнение форматов `RawBLOB` и [TabSeparatedRaw](#tabseparatedraw).
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@@ -1272,7 +1271,7 @@ SELECT * FROM line_as_string;
- строки представлены как длина в формате varint (unsigned [LEB128](https://en.wikipedia.org/wiki/LEB128)), а затем байты строки.
При передаче на вход `RawBLOB` пустых данных, ClickHouse бросает исключение:
${CLICKHOUSE_CLIENT}"${opts[@]}"-q"SELECT groupArray(repeat('a', if(_shard_num == 2, 100000, 1))), number%100000 k from remote('127.{2,3}', system.numbers) GROUP BY k LIMIT 10e6" |& {
# the query should fail earlier on 127.3 and 127.2 should not even go to the memory limit exceeded error.
fgrep-q'DB::Exception: Received from 127.3:9000. DB::Exception: Memory limit (for query) exceeded:'
grep-F-q'DB::Exception: Received from 127.3:9000. DB::Exception: Memory limit (for query) exceeded:'
# while if this will not correctly then it will got the exception from the 127.2:9000 and fail
xargs grep'std::[io]\?stringstream' | grep-v"STYLE_CHECK_ALLOW_STD_STRING_STREAM"&&echo"Use WriteBufferFromOwnString or ReadBufferFromString instead of std::stringstream"
xargs grep-P'std::[io]?stringstream' | grep-v"STYLE_CHECK_ALLOW_STD_STRING_STREAM"&&echo"Use WriteBufferFromOwnString or ReadBufferFromString instead of std::stringstream"
