MariaDB ColumnStore 22.08.8 Release Notes

Overview

MariaDB Enterprise ColumnStore 22.08.8 is a maintenance release of MariaDB Enterprise ColumnStore. MariaDB Enterprise ColumnStore is a columnar storage engine included with MariaDB Enterprise Server.

MariaDB Enterprise ColumnStore 22.08.8 was released on 2023-02-10. This release is of General Availability (GA) maturity.

MariaDB Enterprise ColumnStore 22.08 replaces MariaDB Enterprise ColumnStore 6 in MariaDB Enterprise Server 10.6.

This release of MariaDB Enterprise ColumnStore is included with MariaDB Enterprise Server 10.6.11-6.

Users of earlier MariaDB Enterprise ColumnStore 22.08 releases are encouraged to upgrade.

Notable Changes

• The JSON_ARRAYAGG function is supported for ColumnStore tables as a distributed aggregate function and can be used to aggregate a column's values into a JSON array. (MCOL-5224, MCOL-5227)
  • In previous releases, the following error can be raised when the JSON_ARRAYAGG function is called in a query on a ColumnStore table and the ColumnStore select handler is enabled:

ERROR 1178 (42000): The storage engine for the table doesn't support Non supported aggregate type on the select clause

• Starting with this release, the JSON_ARRAYAGG function can be called in a query on a ColumnStore table when the ColumnStore select handler is enabled. The function accepts a column or expression as an argument. The expression is evaluated for every column in the result set, and all of the values are aggregated into a single JSON array:

CREATE TABLE t (a INT, b INT)
ENGINE=ColumnStore;

INSERT INTO t VALUES
  (1,3), (1,5), (8,2), (5,7),
  (5,6), (10,1), (6,4), (3,9),
  (3,9), (7,2), (7,5), (2,6),
  (9,10), (9,5), (4,8);

SELECT a, JSON_ARRAYAGG(b)
 FROM t
 GROUP BY a;

+------+------------------+
| a    | JSON_ARRAYAGG(b) |
+------+------------------+
|    1 | [3,5]            |
|    2 | [6]              |
|    3 | [9,9]            |
|    4 | [8]              |
|    5 | [7,6]            |
|    6 | [4]              |
|    7 | [2,5]            |
|    8 | [2]              |
|    9 | [10,5]           |
|   10 | [1]              |
+------+------------------+

In many cases, when a query uses the GROUP_CONCAT function, the query can be converted to use the JSON_ARRAYAGG function instead. The primary benefit is that the JSON_ARRAYAGG function returns a JSON array, and there are many functions and external tools available for reading and manipulating JSON.

• Collection of histogram statistics is supported on ColumnStore tables and can be used for cost-based optimization of joins. (MCOL-5191)
  • In previous releases, queries containing complex joins on ColumnStore tables can fail with the following error:

ERROR 1815 (HY000) at line 6: Internal error: IDB-1003: Circular joins are not supported.

• Starting with this release, when histogram statistics are available for a ColumnStore table, the storage engine can use the histogram statistics to determine the uniqueness of a column and process the join graph more efficiently. To collect histogram statistics on a ColumnStore table, use the ANALYZE TABLE statement:

ANALYZE TABLE t1;

Issues Fixed

Can result in data loss

• When ColumnStore is configured to use S3-compatible storage, if the endpoint and region parameters in /etc/columnstore/storagemanager.cnf do not refer to the same region where bucket is located, ColumnStore fails to send data to cloud storage, but does not detect the failure. (MCOL-5177)
  • In previous releases, the endpoint would send ColumnStore an HTTP 301 status code to indicate a failure, but ColumnStore would incorrectly treat it as a success.
    • Starting with this release, ColumnStore correctly identifies the failure and raises an error message:

       S3Storage::putObject(): Bucket location not match provided endpoint:, bucket = BUCKET, endpoint = ENDPOINT.
      

Can result in a hang or crash

• When processing a hash join, ExeMgr can crash with a SIGABRT. (MCOL-5265)

Can result in unexpected behavior

• When a SELECT statement calls SUM(COLUMN=VALUE), the statement fails with an unclear error message. (MCOL-603)
  • In previous releases, the following error is raised:

ERROR 1815 (HY000): Internal error: std::bad_typeid

Starting with this release, the following error is raised: <<code>.

ERROR 1178 (42000): The storage engine for the table doesn't support MCS-2027: Non supported item in aggregate function SUM(COLUMN=VALUE). <</code>.

• When the ANALYZE statement is executed with a SQL statement as an argument, ColumnStore can return an error. (MCOL-1170)
  • In previous releases, the following error is sometimes raised:

ERROR 1815 (HY000): Internal error: Unknown error

• Starting with this release, an error should not be raised, and the execution plan should be printed:

ANALYZE SELECT * FROM t1 WHERE c1 = 1;

+------+---------------+-------+------+---------------+------+---------+------+------+--------+----------+------------+-------+
| id   | select_type   | table | type | possible_keys | key  | key_len | ref  | rows | r_rows | filtered | r_filtered | Extra |
+------+---------------+-------+------+---------------+------+---------+------+------+--------+----------+------------+-------+
|    1 | PUSHED SELECT | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL | NULL   |     NULL |       NULL | NULL  |
+------+---------------+-------+------+---------------+------+---------+------+------+--------+----------+------------+-------+

• When a column is added to a table on a primary node with multi-node ColumnStore, ColumnStore tries to add the new column to the table twice on the replica nodes, which causes a replication failure. (MCOL-5000)
  • In previous releases, when replication failed, messages like the following appear in the MariaDB error log: <<ocde>> [ERROR] Slave SQL: Error 'Got error 1815 "Unknown error 1815" from storage engine ColumnStore' on query. Default database: 'db1'. Query: 'ALTER TABLE t1 ADD COLUMN (col2 varchar(100))', Gtid GTID_POS, Internal MariaDB error code: 1030 [Warning] Slave: Got error 1815 "Unknown error 1815" from storage engine ColumnStore Error_code: 1030 [ERROR] Error running query, slave SQL thread aborted. Fix the problem, and restart the slave SQL thread with "SLAVE START". We stopped at log 'LOG_FILE' position LOG_POS; GTID position 'GTID_POS' <</code>>
  • Starting with this release, ColumnStore only adds the new column to the table once on the replica nodes, so the replication failure does not occur.

• When querytstats is enabled, if a query contains a LEFT JOIN and the ON clause contains the LOWER() function, an error is written to the ColumnStore log. (MCOL-5223)
  • In previous releases, the following error is written to the ColumnStore log:

1e3afaf1eaef Calpont[135]: 37.906020 |0|0|0| E 00 CAL0000: /home/buildbot/buildbot/padding_for_CPACK_RPM_BUILD_SOURCE_DIRS_PREFIX/mariadb-10.6.8/storage/columnstore/columnstore/dbcon/joblist/tuplehashjoin.cpp@1095: assertion 'idlsz > 1' failed

Starting with this release, the query can be executed without raising an error.

• When the TRUNCATE() function is called with a CHAR or VARCHAR column that contains numeric characters, an incorrect value is returned. (MCOL-5248)
• When multi-node ColumnStore is configured to use shared local storage, replica nodes can overwrite their local copies of the extent map files multiple times during shutdown. (MCOL-5302)
• When columnstore_use_import_for_batchinsert=ON is set on multi-node ColumnStore, INSERT INTO .. SELECT statements in a transaction report that rows were inserted, even though no rows are inserted. (MCOL-5367)
• When ExeMgr finishes serving a request from MariaDB Server, ExeMgr's TCP connection can remain open, and its thread can continue running, which can cause ColumnStore to use more resources than required. (MCOL-5384)

Platforms

In alignment to the enterprise lifecycle, MariaDB Enterprise ColumnStore 22.08.8 is provided for:

• CentOS 7 (x86_64)
• Debian 11 (x86_64, ARM64)
• Red Hat Enterprise Linux 7 (x86_64)
• Red Hat Enterprise Linux 8 (x86_64, ARM64)
• Red Hat Enterprise Linux 9 (x86_64, ARM64)
• Rocky Linux 8 (x86_64, ARM64)
• Rocky Linux 9 (x86_64, ARM64)
• Ubuntu 20.04 (x86_64, ARM64)
• Ubuntu 22.04 (x86_64, ARM64)

Installation Instructions

• ColumnStore Object Storage Topology with MariaDB Enterprise Server 10.6 and MariaDB Enterprise ColumnStore 23.10
• ColumnStore Shared Local Storage Topology with MariaDB Enterprise Server 10.6 and MariaDB Enterprise ColumnStore 23.10
• HTAP Topology with MariaDB Enterprise Server 10.6 and MariaDB Enterprise ColumnStore 23.10
• Single-Node Enterprise ColumnStore 23.10 with MariaDB Enterprise Server 10.6 and Object Storage
• Single-Node Enterprise ColumnStore 23.10 with MariaDB Enterprise Server 10.6

Upgrade Instructions

• Upgrade Multi-Node MariaDB Enterprise ColumnStore from 6 to 23.10
• Major Release Upgrades for MariaDB Enterprise ColumnStore