محرك الجدول MergeTree

CREATE TABLE [IF NOT EXISTS] [db.]table_name [ON CLUSTER cluster]
(
    name1 [type1] [[NOT] NULL] [DEFAULT|MATERIALIZED|ALIAS|EPHEMERAL expr1] [COMMENT ...] [CODEC(codec1)] [STATISTICS(stat1)] [TTL expr1] [PRIMARY KEY] [SETTINGS (name = value, ...)],
    name2 [type2] [[NOT] NULL] [DEFAULT|MATERIALIZED|ALIAS|EPHEMERAL expr2] [COMMENT ...] [CODEC(codec2)] [STATISTICS(stat2)] [TTL expr2] [PRIMARY KEY] [SETTINGS (name = value, ...)],
    ...
    INDEX index_name1 expr1 TYPE type1(...) [GRANULARITY value1],
    INDEX index_name2 expr2 TYPE type2(...) [GRANULARITY value2],
    ...
    PROJECTION projection_name_1 (SELECT <COLUMN LIST EXPR> [GROUP BY] [ORDER BY]),
    PROJECTION projection_name_2 (SELECT <COLUMN LIST EXPR> [GROUP BY] [ORDER BY])
) ENGINE = MergeTree()
ORDER BY expr
[PARTITION BY expr]
[PRIMARY KEY expr]
[SAMPLE BY expr]
[TTL expr
    [DELETE|TO DISK 'xxx'|TO VOLUME 'xxx' [, ...] ]
    [WHERE conditions]
    [GROUP BY key_expr [SET v1 = aggr_func(v1) [, v2 = aggr_func(v2) ...]] ] ]
[SETTINGS name = value, ...]

ENGINE MergeTree() PARTITION BY toYYYYMM(EventDate) ORDER BY (CounterID, EventDate, intHash32(UserID)) SAMPLE BY intHash32(UserID) SETTINGS index_granularity=8192

Whole data:     [---------------------------------------------]
CounterID:      [aaaaaaaaaaaaaaaaaabbbbcdeeeeeeeeeeeeefgggggggghhhhhhhhhiiiiiiiiikllllllll]
Date:           [1111111222222233331233211111222222333211111112122222223111112223311122333]
Marks:           |      |      |      |      |      |      |      |      |      |      |
                a,1    a,2    a,3    b,3    e,2    e,3    g,1    h,2    i,1    i,3    l,3
Marks numbers:   0      1      2      3      4      5      6      7      8      9      10

ENGINE MergeTree()
PARTITION BY toYYYYMM(EventDate)
ORDER BY (CounterID, EventDate)
SETTINGS index_granularity=8192

SELECT count() FROM table
WHERE EventDate = toDate(now())
AND CounterID = 34

SELECT count() FROM table
WHERE EventDate = toDate(now())
AND (CounterID = 34 OR CounterID = 42)

SELECT count() FROM table
WHERE ((EventDate >= toDate('2014-01-01')
AND EventDate <= toDate('2014-01-31')) OR EventDate = toDate('2014-05-01'))
AND CounterID IN (101500, 731962, 160656)
AND (CounterID = 101500 OR EventDate != toDate('2014-05-01'))

SELECT count() FROM table WHERE CounterID = 34 OR URL LIKE '%upyachka%'

ENGINE = MergeTree()
ORDER BY length(user_id)

SELECT * FROM table WHERE user_id = 'alice';
SELECT * FROM table WHERE user_id IN ('alice', 'bob');
SELECT * FROM table WHERE has(['alice', 'bob'], user_id);

ENGINE = MergeTree()
ORDER BY hex(p)

ENGINE = MergeTree()
ORDER BY reverse(tuple(reverse(p), hex(p)))

SELECT * FROM table WHERE p != 'abc';
SELECT * FROM table WHERE p NOT IN ('abc', '12345');
SELECT * FROM table WHERE NOT has(['abc', '12345'], p);

INDEX index_name expr TYPE type(...) [GRANULARITY granularity_value]

CREATE TABLE table_name
(
    u64 UInt64,
    i32 Int32,
    s String,
    ...
    INDEX idx1 u64 TYPE bloom_filter GRANULARITY 3,
    INDEX idx2 u64 * i32 TYPE minmax GRANULARITY 3,
    INDEX idx3 u64 * length(s) TYPE set(1000) GRANULARITY 4
) ENGINE = MergeTree()
...

SELECT count() FROM table WHERE u64 == 10;
SELECT count() FROM table WHERE u64 * i32 >= 1234
SELECT count() FROM table WHERE u64 * length(s) == 1234

-- on columns of type Map:
INDEX map_key_index mapKeys(map_column) TYPE bloom_filter
INDEX map_value_index mapValues(map_column) TYPE bloom_filter

-- on columns of type JSON:
INDEX json_paths_index JSONAllPaths(json_column) TYPE bloom_filter

-- on columns of type Tuple:
INDEX tuple_1_index tuple_column.1 TYPE bloom_filter
INDEX tuple_2_index tuple_column.2 TYPE bloom_filter

-- on columns of type Nested:
INDEX nested_1_index col.nested_col1 TYPE bloom_filter
INDEX nested_2_index col.nested_col2 TYPE bloom_filter

--- estimate number of bits in the filter
SELECT bfEstimateBmSize(4300, 0.0001) / 8 AS size_of_bloom_filter_in_bytes;

┌─size_of_bloom_filter_in_bytes─┐
│                         10304 │
└───────────────────────────────┘

--- estimate number of hash functions
SELECT bfEstimateFunctions(4300, bfEstimateBmSize(4300, 0.0001)) as number_of_hash_functions

┌─number_of_hash_functions─┐
│                       13 │
└──────────────────────────┘

SELECT <column list expr> [GROUP BY] <group keys expr> [ORDER BY] <expr>

PROJECTION <name> INDEX <index_expr> TYPE <index_type>

CREATE TABLE example
(
    id UInt64,
    region String,
    user_id UInt32,
    PROJECTION region_proj INDEX region TYPE basic,
    PROJECTION uid_proj INDEX user_id TYPE basic
)
ENGINE = MergeTree
ORDER BY id;

TTL time_column
TTL time_column + interval

TTL date_time + INTERVAL 1 MONTH
TTL date_time + INTERVAL 15 HOUR

CREATE TABLE tab
(
    d DateTime,
    a Int TTL d + INTERVAL 1 MONTH,
    b Int TTL d + INTERVAL 1 MONTH,
    c String
)
ENGINE = MergeTree
PARTITION BY toYYYYMM(d)
ORDER BY d;

ALTER TABLE tab
    MODIFY COLUMN
    c String TTL d + INTERVAL 1 DAY;

ALTER TABLE tab
    MODIFY COLUMN
    c String TTL d + INTERVAL 1 MONTH;

TTL expr
    [DELETE|RECOMPRESS codec_name1|TO DISK 'xxx'|TO VOLUME 'xxx'][, DELETE|RECOMPRESS codec_name2|TO DISK 'aaa'|TO VOLUME 'bbb'] ...
    [WHERE conditions]
    [GROUP BY key_expr [SET v1 = aggr_func(v1) [, v2 = aggr_func(v2) ...]] ]

TTL time_column + INTERVAL 1 MONTH DELETE WHERE column = 'value'

CREATE TABLE tab
(
    d DateTime,
    a Int
)
ENGINE = MergeTree
PARTITION BY toYYYYMM(d)
ORDER BY d
TTL d + INTERVAL 1 MONTH DELETE,
    d + INTERVAL 1 WEEK TO VOLUME 'aaa',
    d + INTERVAL 2 WEEK TO DISK 'bbb';

ALTER TABLE tab
    MODIFY TTL d + INTERVAL 1 DAY;

CREATE TABLE table_with_where
(
    d DateTime,
    a Int
)
ENGINE = MergeTree
PARTITION BY toYYYYMM(d)
ORDER BY d
TTL d + INTERVAL 1 MONTH DELETE WHERE toDayOfWeek(d) = 1;

CREATE TABLE table_for_recompression
(
    d DateTime,
    key UInt64,
    value String
) ENGINE MergeTree()
ORDER BY tuple()
PARTITION BY key
TTL d + INTERVAL 1 MONTH RECOMPRESS CODEC(ZSTD(17)), d + INTERVAL 1 YEAR RECOMPRESS CODEC(LZ4HC(10))
SETTINGS min_rows_for_wide_part = 0, min_bytes_for_wide_part = 0;

CREATE TABLE table_for_aggregation
(
    d DateTime,
    k1 Int,
    k2 Int,
    x Int,
    y Int
)
ENGINE = MergeTree
ORDER BY (k1, k2)
TTL d + INTERVAL 1 MONTH GROUP BY k1, k2 SET x = max(x), y = min(y);

<storage_configuration>
    <disks>
        <disk_name_1> <!-- disk name -->
            <path>/mnt/fast_ssd/clickhouse/</path>
        </disk_name_1>
        <disk_name_2>
            <path>/mnt/hdd1/clickhouse/</path>
            <keep_free_space_bytes>10485760</keep_free_space_bytes>
        </disk_name_2>
        <disk_name_3>
            <path>/mnt/hdd2/clickhouse/</path>
            <keep_free_space_bytes>10485760</keep_free_space_bytes>
        </disk_name_3>

        ...
    </disks>

    ...
</storage_configuration>

<storage_configuration>
    ...
    <policies>
        <policy_name_1>
            <volumes>
                <volume_name_1>
                    <disk>disk_name_from_disks_configuration</disk>
                    <max_data_part_size_bytes>1073741824</max_data_part_size_bytes>
                    <load_balancing>round_robin</load_balancing>
                </volume_name_1>
                <volume_name_2>
                    <!-- configuration -->
                </volume_name_2>
                <!-- more volumes -->
            </volumes>
            <move_factor>0.2</move_factor>
        </policy_name_1>
        <policy_name_2>
            <!-- configuration -->
        </policy_name_2>

        <!-- more policies -->
    </policies>
    ...
</storage_configuration>

<storage_configuration>
    ...
    <policies>
        <hdd_in_order> <!-- policy name -->
            <volumes>
                <single> <!-- volume name -->
                    <disk>disk1</disk>
                    <disk>disk2</disk>
                </single>
            </volumes>
        </hdd_in_order>

        <moving_from_ssd_to_hdd>
            <volumes>
                <hot>
                    <disk>fast_ssd</disk>
                    <max_data_part_size_bytes>1073741824</max_data_part_size_bytes>
                </hot>
                <cold>
                    <disk>disk1</disk>
                </cold>
            </volumes>
            <move_factor>0.2</move_factor>
        </moving_from_ssd_to_hdd>

        <small_jbod_with_external_no_merges>
            <volumes>
                <main>
                    <disk>jbod1</disk>
                </main>
                <external>
                    <disk>external</disk>
                </external>
            </volumes>
        </small_jbod_with_external_no_merges>
    </policies>
    ...
</storage_configuration>

CREATE TABLE table_with_non_default_policy (
    EventDate Date,
    OrderID UInt64,
    BannerID UInt64,
    SearchPhrase String
) ENGINE = MergeTree
ORDER BY (OrderID, BannerID)
PARTITION BY toYYYYMM(EventDate)
SETTINGS storage_policy = 'moving_from_ssd_to_hdd'

<storage_configuration>
    ...
    <disks>
        <s3>
            <type>s3</type>
            <support_batch_delete>true</support_batch_delete>
            <endpoint>https://clickhouse-public-datasets.s3.amazonaws.com/my-bucket/root-path/</endpoint>
            <access_key_id>your_access_key_id</access_key_id>
            <secret_access_key>your_secret_access_key</secret_access_key>
            <region></region>
            <header>Authorization: Bearer SOME-TOKEN</header>
            <server_side_encryption_customer_key_base64>your_base64_encoded_customer_key</server_side_encryption_customer_key_base64>
            <server_side_encryption_kms_key_id>your_kms_key_id</server_side_encryption_kms_key_id>
            <server_side_encryption_kms_encryption_context>your_kms_encryption_context</server_side_encryption_kms_encryption_context>
            <server_side_encryption_kms_bucket_key_enabled>true</server_side_encryption_kms_bucket_key_enabled>
            <proxy>
                <uri>http://proxy1</uri>
                <uri>http://proxy2</uri>
            </proxy>
            <connect_timeout_ms>10000</connect_timeout_ms>
            <request_timeout_ms>5000</request_timeout_ms>
            <retry_attempts>10</retry_attempts>
            <single_read_retries>4</single_read_retries>
            <min_bytes_for_seek>1000</min_bytes_for_seek>
            <metadata_path>/var/lib/clickhouse/disks/s3/</metadata_path>
            <skip_access_check>false</skip_access_check>
        </s3>
        <s3_cache>
            <type>cache</type>
            <disk>s3</disk>
            <path>/var/lib/clickhouse/disks/s3_cache/</path>
            <max_size>10Gi</max_size>
        </s3_cache>
    </disks>
    ...
</storage_configuration>

<storage_configuration>
    <disks>
        <s3_bucket1>
            <type>s3</type>
            <endpoint>https://s3.amazonaws.com/bucket-1/data/</endpoint>
            <access_key_id>your_access_key_id</access_key_id>
            <secret_access_key>your_secret_access_key</secret_access_key>
        </s3_bucket1>
        <s3_bucket2>
            <type>s3</type>
            <endpoint>https://s3.amazonaws.com/bucket-2/data/</endpoint>
            <access_key_id>your_access_key_id</access_key_id>
            <secret_access_key>your_secret_access_key</secret_access_key>
        </s3_bucket2>
    </disks>
    <policies>
        <s3_multi_bucket>
            <volumes>
                <main>
                    <disk>s3_bucket1</disk>
                    <disk>s3_bucket2</disk>
                </main>
            </volumes>
        </s3_multi_bucket>
    </policies>
</storage_configuration>

<storage_configuration>
    <disks>
        <local_ssd>
            <path>/mnt/fast_ssd/clickhouse/</path>
        </local_ssd>
        <s3_cold>
            <type>s3</type>
            <endpoint>https://s3.amazonaws.com/cold-storage/data/</endpoint>
            <access_key_id>your_access_key_id</access_key_id>
            <secret_access_key>your_secret_access_key</secret_access_key>
        </s3_cold>
    </disks>
    <policies>
        <local_to_s3>
            <volumes>
                <hot>
                    <disk>local_ssd</disk>
                    <max_data_part_size_bytes>1073741824</max_data_part_size_bytes>
                </hot>
                <cold>
                    <disk>s3_cold</disk>
                </cold>
            </volumes>
            <move_factor>0.2</move_factor>
        </local_to_s3>
    </policies>
</storage_configuration>

CREATE TABLE tab
(
    a Int64 STATISTICS(tdigest, uniq),
    b Float64
)
ENGINE = MergeTree
ORDER BY a

ALTER TABLE tab ADD STATISTICS b TYPE tdigest, uniq;
ALTER TABLE tab DROP STATISTICS a;

-- Create a table with basic statistics on the 'value' column
CREATE TABLE test_stats
(
    id UInt64,
    value Int64 STATISTICS(basic)
)
ENGINE = MergeTree
ORDER BY id;

SYSTEM STOP MERGES test_stats;

-- Insert data in separate inserts to create multiple parts
INSERT INTO test_stats SELECT number, number FROM numbers(1000); -- Part 1: value range [0, 999]
INSERT INTO test_stats SELECT number, number + 10000 FROM numbers(1000); -- Part 2: value range [10000, 10999]

SET use_statistics_for_part_pruning = 1;

-- This query will skip Part 1 entirely because its max value (999) < 5000
SELECT count() FROM test_stats WHERE value > 5000;

-- Use EXPLAIN to see the pruning effect
EXPLAIN indexes = 1 SELECT count() FROM test_stats WHERE value > 5000;
-- The output will show "Parts: 1/2" indicating one part was pruned

CREATE TABLE tab
(
    id Int64,
    document String SETTINGS (min_compress_block_size = 16777216, max_compress_block_size = 16777216)
)
ENGINE = MergeTree
ORDER BY id

ALTER TABLE tab MODIFY COLUMN document REMOVE SETTINGS;

ALTER TABLE tab MODIFY COLUMN document MODIFY SETTING min_compress_block_size = 8192;

ALTER TABLE tab MODIFY COLUMN document RESET SETTING min_compress_block_size;