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flynn 2023-06-23 14:29:49 +00:00
parent e7d1dfb704
commit 733e2905c7
3 changed files with 76 additions and 41 deletions
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78
docs/en/operations/system-tables/merge_tree_settings.md
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@ -7,11 +7,17 @@ Contains information about settings for `MergeTree` tables.
Columns:
- `name` (String) — Setting name.
- `value` (String) — Setting value.
- `description` (String) — Setting description.
- `type` (String) — Setting type (implementation specific string value).
- `changed` (UInt8) — Whether the setting was explicitly defined in the config or explicitly changed.
- `name` ([String](../../sql-reference/data-types/string.md)) — Setting name.
- `value` ([String](../../sql-reference/data-types/string.md)) — Setting value.
- `changed` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Whether the setting was explicitly defined in the config or explicitly changed.
- `description` ([String](../../sql-reference/data-types/string.md)) — Setting description.
- `min` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Minimum value of the setting, if any is set via [constraints](../../operations/settings/constraints-on-settings.md#constraints-on-settings). If the setting has no minimum value, contains [NULL](../../sql-reference/syntax.md#null-literal).
- `max` ([Nullable](../../sql-reference/data-types/nullable.md)([String](../../sql-reference/data-types/string.md))) — Maximum value of the setting, if any is set via [constraints](../../operations/settings/constraints-on-settings.md#constraints-on-settings). If the setting has no maximum value, contains [NULL](../../sql-reference/syntax.md#null-literal).
- `readonly` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether the current user can change the setting:
- `0` — Current user can change the setting.
- `1` — Current user can’t change the setting.
- `type` ([String](../../sql-reference/data-types/string.md)) — Setting type (implementation specific string value).
- `is_obsolete` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) _ Shows whether a setting is obsolete.
**Example**
```sql
@ -19,37 +25,53 @@ SELECT * FROM system.merge_tree_settings LIMIT 4 FORMAT Vertical;
```
```response
Row 1:
Row 1:
──────
name: min_compress_block_size
value: 0
changed: 0
description: When granule is written, compress the data in buffer if the size of pending uncompressed data is larger or equal than the specified threshold. If this setting is not set, the corresponding global setting is used.
min: ____
max: ____
readonly: 0
type: UInt64
is_obsolete: 0
Row 2:
──────
name: max_compress_block_size
value: 0
changed: 0
description: Compress the pending uncompressed data in buffer if its size is larger or equal than the specified threshold. Block of data will be compressed even if the current granule is not finished. If this setting is not set, the corresponding global setting is used.
min: ____
max: ____
readonly: 0
type: UInt64
is_obsolete: 0
Row 3:
──────
name: index_granularity
value: 8192
changed: 0
description: How many rows correspond to one primary key value.
type: SettingUInt64
Row 2:
──────
name: min_bytes_for_wide_part
value: 0
changed: 0
description: Minimal uncompressed size in bytes to create part in wide format instead of compact
type: SettingUInt64
Row 3:
──────
name: min_rows_for_wide_part
value: 0
changed: 0
description: Minimal number of rows to create part in wide format instead of compact
type: SettingUInt64
min: ____
max: ____
readonly: 0
type: UInt64
is_obsolete: 0
Row 4:
──────
name: merge_max_block_size
value: 8192
name: max_digestion_size_per_segment
value: 268435456
changed: 0
description: How many rows in blocks should be formed for merge operations.
type: SettingUInt64
description: Max number of bytes to digest per segment to build GIN index.
min: ____
max: ____
readonly: 0
type: UInt64
is_obsolete: 0
4 rows in set. Elapsed: 0.001 sec.
4 rows in set. Elapsed: 0.009 sec.
```

25
docs/en/operations/system-tables/server_settings.md
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@ -14,6 +14,7 @@ Columns:
- `changed` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether a setting was specified in `config.xml`
- `description` ([String](../../sql-reference/data-types/string.md)) — Short server setting description.
- `type` ([String](../../sql-reference/data-types/string.md)) — Server setting value type.
- `is_obsolete` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) _ Shows whether a setting is obsolete.
**Example**
@ -26,14 +27,22 @@ WHERE name LIKE '%thread_pool%'
```
``` text
┌─name─────────────────────────┬─value─┬─default─┬─changed─┬─description─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─type───┐
│ max_thread_pool_size │ 5000 │ 10000 │ 1 │ The maximum number of threads that could be allocated from the OS and used for query execution and background operations. │ UInt64 │
│ max_thread_pool_free_size │ 1000 │ 1000 │ 0 │ The maximum number of threads that will always stay in a global thread pool once allocated and remain idle in case of insufficient number of tasks. │ UInt64 │
│ thread_pool_queue_size │ 10000 │ 10000 │ 0 │ The maximum number of tasks that will be placed in a queue and wait for execution. │ UInt64 │
│ max_io_thread_pool_size │ 100 │ 100 │ 0 │ The maximum number of threads that would be used for IO operations │ UInt64 │
│ max_io_thread_pool_free_size │ 0 │ 0 │ 0 │ Max free size for IO thread pool. │ UInt64 │
│ io_thread_pool_queue_size │ 10000 │ 10000 │ 0 │ Queue size for IO thread pool. │ UInt64 │
└──────────────────────────────┴───────┴─────────┴─────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴────────┘
┌─name────────────────────────────────────────_─value─_─default─_─changed─_─description──────────────────────────────────────────────────────────────────────────────────────────────────────
───────────────────────────────────_─type───_─is_obsolete─┐
│ max_thread_pool_size │ 10000 │ 10000 │ 1 │ The maximum number of threads that could be allocated from the OS and used for query execution and background operations. │ UInt64 │ 0 │
│ max_thread_pool_free_size │ 1000 │ 1000 │ 0 │ The maximum number of threads that will always stay in a global thread pool once allocated and remain idle in case of insufficient number of tasks. │ UInt64 │ 0 │
│ thread_pool_queue_size │ 10000 │ 10000 │ 0 │ The maximum number of tasks that will be placed in a queue and wait for execution. │ UInt64 │ 0 │
│ max_io_thread_pool_size │ 100 │ 100 │ 0 │ The maximum number of threads that would be used for IO operations │ UInt64 │ 0 │
│ max_io_thread_pool_free_size │ 0 │ 0 │ 0 │ Max free size for IO thread pool. │ UInt64 │ 0 │
│ io_thread_pool_queue_size │ 10000 │ 10000 │ 0 │ Queue size for IO thread pool. │ UInt64 │ 0 │
│ max_active_parts_loading_thread_pool_size │ 64 │ 64 │ 0 │ The number of threads to load active set of data parts (Active ones) at startup. │ UInt64 │ 0 │
│ max_outdated_parts_loading_thread_pool_size │ 32 │ 32 │ 0 │ The number of threads to load inactive set of data parts (Outdated ones) at startup. │ UInt64 │ 0 │
│ max_parts_cleaning_thread_pool_size │ 128 │ 128 │ 0 │ The number of threads for concurrent removal of inactive data parts. │ UInt64 │ 0 │
│ max_backups_io_thread_pool_size │ 1000 │ 1000 │ 0 │ The maximum number of threads that would be used for IO operations for BACKUP queries │ UInt64 │ 0 │
│ max_backups_io_thread_pool_free_size │ 0 │ 0 │ 0 │ Max free size for backups IO thread pool. │ UInt64 │ 0 │
│ backups_io_thread_pool_queue_size │ 0 │ 0 │ 0 │ Queue size for backups IO thread pool. │ UInt64 │ 0 │
└─────────────────────────────────────────────┴───────┴─────────┴─────────┴──────────────────────────────────────────────────────────────────────────────────────────────────────────────────
───────────────────────────────────┴────────┴─────────────┘
```
Using of `WHERE changed` can be useful, for example, when you want to check

14
docs/en/operations/system-tables/settings.md
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@ -17,6 +17,7 @@ Columns:
- `0` — Current user can change the setting.
- `1` — Current user can’t change the setting.
- `default` ([String](../../sql-reference/data-types/string.md)) — Setting default value.
- `is_obsolete` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) _ Shows whether a setting is obsolete.
**Example**
@ -29,11 +30,14 @@ WHERE name LIKE '%min_i%'
```
``` text
┌─name────────────────────────────────────────┬─value─────┬─changed─┬─description───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─min──┬─max──┬─readonly─┐
│ min_insert_block_size_rows │ 1048576 │ 0 │ Squash blocks passed to INSERT query to specified size in rows, if blocks are not big enough. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │
│ min_insert_block_size_bytes │ 268435456 │ 0 │ Squash blocks passed to INSERT query to specified size in bytes, if blocks are not big enough. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │
│ read_backoff_min_interval_between_events_ms │ 1000 │ 0 │ Settings to reduce the number of threads in case of slow reads. Do not pay attention to the event, if the previous one has passed less than a certain amount of time. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │
└─────────────────────────────────────────────┴───────────┴─────────┴───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴──────┴──────┴──────────┘
┌─name───────────────────────────────────────────────_─value─────_─changed─_─description───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────_─min──_─max──_─readonly─_─type─────────_─default───_─alias_for─_─is_obsolete─┐
│ min_insert_block_size_rows │ 1048449 │ 0 │ Squash blocks passed to INSERT query to specified size in rows, if blocks are not big enough. │ ____ │ ____ │ 0 │ UInt64 │ 1048449 │ │ 0 │
│ min_insert_block_size_bytes │ 268402944 │ 0 │ Squash blocks passed to INSERT query to specified size in bytes, if blocks are not big enough. │ ____ │ ____ │ 0 │ UInt64 │ 268402944 │ │ 0 │
│ min_insert_block_size_rows_for_materialized_views │ 0 │ 0 │ Like min_insert_block_size_rows, but applied only during pushing to MATERIALIZED VIEW (default: min_insert_block_size_rows) │ ____ │ ____ │ 0 │ UInt64 │ 0 │ │ 0 │
│ min_insert_block_size_bytes_for_materialized_views │ 0 │ 0 │ Like min_insert_block_size_bytes, but applied only during pushing to MATERIALIZED VIEW (default: min_insert_block_size_bytes) │ ____ │ ____ │ 0 │ UInt64 │ 0 │ │ 0 │
│ read_backoff_min_interval_between_events_ms │ 1000 │ 0 │ Settings to reduce the number of threads in case of slow reads. Do not pay attention to the event, if the previous one has passed less than a certain amount of time. │ ____ │ ____ │ 0 │ Milliseconds │ 1000 │ │ 0 │
└────────────────────────────────────────────────────┴───────────┴─────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────
──────────────────────────────────────────────────────┴──────┴──────┴──────────┴──────────────┴───────────┴───────────┴─────────────┘
```
Using of `WHERE changed` can be useful, for example, when you want to check: