Commit Graph

5 Commits

Author SHA1 Message Date
Amos Bird
1cbd05ae9e
Correctly prevent nullable primary keys if necessary. 2021-12-27 17:32:37 +08:00
Amos Bird
29c87b2f44
Fix nullable key 2021-11-29 20:49:01 +08:00
Azat Khuzhin
038241b6ed Add new index data skipping minmax index format for proper Nullable support
Note, that it cannot be done w/o new extension, since index does not
have any header.

v2: use IDisk interface for existence check
v3: remove extra file existence check
v4: fix MATERIALIZE INDEX
2021-08-08 19:30:12 +03:00
Azat Khuzhin
dee27fcbb9 Fix on-disk format breakage for secondary indices over Nullable column
[1] breaks on disk format (and the relevant change in the:

  [1]: https://github.com/ClickHouse/ClickHouse/pull/12455#discussion_r682830812

Too bad that I checked this patchset only for compatibility after
reverting this patch [2] (use case: I've applied it manually, then
revert it, and data skipping indexes over Nullable column had been
broken)

  [2]: https://github.com/ClickHouse/ClickHouse/pull/12455#issuecomment-823423772

But this patchset actually breaks compatibility with older versions of
clickhouse for Nullable data skipping indexes after simple upgrade:

Here is a simple reproducer:

    --
    -- run this with 21.6 or similar (i.e. w/o this patch)
    --

    CREATE TABLE data
    (
        `key` Int,
        `value` Nullable(Int),
        INDEX value_index value TYPE minmax GRANULARITY 1
    )
    ENGINE = MergeTree
    ORDER BY key;

    INSERT INTO data SELECT
        number,
        number
    FROM numbers(10000);

    SELECT * FROM data WHERE value = 20000 SETTINGS force_data_skipping_indices = 'value_index' SETTINGS force_data_skipping_indices = 'value_index', max_rows_to_read=1;

Now upgrade and run the query again:

    SELECT * FROM data WHERE value = 20000 SETTINGS force_data_skipping_indices = 'value_index' SETTINGS force_data_skipping_indices = 'value_index', max_rows_to_read=1;

And it will fail because of on disk format changes:

    $ ll --time-style=+ data/*/data/all_1_1_0/skp*.idx
    -rw-r----- 1 azat azat 36  data/with_nullable_patch/data/all_1_1_0/skp_idx_value_index.idx
    -rw-r----- 1 azat azat 37  data/without_nullable_patch/data/all_1_1_0/skp_idx_value_index.idx

    $ md5sum data/*/data/all_1_1_0/skp*.idx
    a19c95c4a14506c65665a1e30ab404bf  data/with_nullable_patch/data/all_1_1_0/skp_idx_value_index.idx
    e50e2fcfa873b232196623d56ab26105  data/without_nullable_patch/data/all_1_1_0/skp_idx_value_index.idx

Note, that there is no stable release with this patch included yet, so
no need to backport.

Also note that you may create data skipping indexes over Nullable
column even before [3].

  [3]: https://github.com/ClickHouse/ClickHouse/pull/12455

v2: break cases when granulas has Null in values due to backward
compatibility
2021-08-05 00:19:38 +03:00
Amos Bird
f2ed5ef42b
Nullable primary key with correct KeyCondition 2021-06-18 23:04:24 +08:00