[Stable] 2.5.18
RRelease date: Jan 10, 2024
New Features
- Users can set or modify session variables when they CREATE or ALTER asynchronous materialized views. #37401
Improvements
- When using JDK, the default GC algorithm is G1. #37498
- The result returned by the SHOW ROUTINE LOAD statement now includes the timestamps of consumption messages from each partition. #36222
Behavior Change
- Added the session variable
enable_materialized_view_for_insert
, which controls whether materialized views rewrite the queries in INSERT INTO SELECT statements. The default value isfalse
. #37505 - Added the session variable
enable_strict_order_by
. When this variable is set to the default valueTRUE
, an error is reported for such a query pattern: Duplicate alias is used in different expressions of the query and this alias is also a sorting field in ORDER BY, for example,select distinct t1.* from tbl1 t1 order by t1.k1;
. The logic is the same as that in v2.3 and earlier. When this variable is set toFALSE
, a loose deduplication mechanism is used, which processes such queries as valid SQL queries. #37910
Parameter Change
- Added session variables
transaction_read_only
andtx_read_only
to specify the transaction access mode, which are compatible with MySQL versions 5.7.20 and above. #37249 - Added the FE configuration item
routine_load_unstable_threshold_second
. #36222 - Added the FE configuration item
http_worker_threads_num
, which specifies the number of threads for HTTP server to deal with HTTP requests. The default value is0
. If the value for this parameter is set to a negative value or 0, the actual thread number is twice the number of CPU cores. #37530 - Added the BE configuration item
pindex_major_compaction_limit_per_disk
to configure the maximum concurrency of compaction on a disk. This addresses the issue of uneven I/O across disks due to compaction. This issue can cause excessively high I/O for certain disks. The default value is1
. #37695
Bug Fixes
Fixed the following issues:
- Using NaN (Not a Number) columns as ORDER BY columns may cause BEs to crash. #30759
- Failure to update primary key indexes may cause the error "get_applied_rowsets failed". #27488
- Hive metadata in Hive catalogs is not automatically refreshed when new fields are added to Hive tables. #37668
- When
SELECT ... FROM ... INTO OUTFILE
is executed to export data into CSV files, the error "Unmatched number of columns" is reported if the FROM clause contains multiple constants. #38045 - In some cases,
bitmap_to_string
may return incorrect result due to data type overflow. #37405