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TiDB 5.0.3 Release Notes
Release date: July 2, 2021
TiDB version: 5.0.3
Compatibility Changes
TiDB
- After a v4.0 cluster is upgraded to v5.0 or a later version (dev or v5.1), the default value of the
tidb_multi_statement_mode
variable changes fromWARN
toOFF
- TiDB is now compatible with MySQL 5.7's noop variable
innodb_default_row_format
. Setting this variable will have no effect. #23541
- After a v4.0 cluster is upgraded to v5.0 or a later version (dev or v5.1), the default value of the
Feature Enhancements
Tools
Improvements
TiDB
- Support pushing down the
TopN
operator to TiFlash #25162 - Support pushing down the built-in function
json_unquote()
to TiKV #24415 - Support removing the union branch from the dual table #25614
- Support pushing down the built-in function
replace()
to TiFlash #25565 - Support pushing down the built-in functions
unix_timestamp()
,concat()
,year()
,day()
,datediff()
,datesub()
, andconcat_ws()
to TiFlash #25564 - Optimize the aggregate operator's cost factor #25241
- Support pushing down the
Limit
operator to TiFlash #25159 - Support pushing down the built-in function
str_to_date
to TiFlash #25148 - Allow the MPP outer join to choose the build table based on the table row count #25142
- Support pushing down the built-in functions
left()
,right()
, andabs()
to TiFlash #25133 - Support pushing down the Broadcast Cartesian join to TiFlash #25106
- Support pushing down the
Union All
operator to TiFlash #25051 - Support balancing the MPP query workload among different TiFlash nodes based on Regions #24724
- Support invalidating stale Regions in the cache after the MPP query is executed #24432
- Improve the MySQL compatibility of the built-in function
str_to_date
for the format specifiers%b/%M/%r/%T
#25767
- Support pushing down the
TiKV
PD
- Update TiDB Dashboard to v2021.06.15.1 #3798
TiFlash
- Support casting the
STRING
type to theDOUBLE
type - Support the
STR_TO_DATE()
function - Optimize the non-joined data in right outer join using multiple threads
- Support the Cartesian join
- Support the
LEFT()
andRIGHT()
functions - Support automatically invalidating stale Regions in MPP queries
- Support the
ABS()
function
- Support casting the
Tools
Bug Fixes
TiDB
- Fix the issue that an incorrect result is returned when using merge join on the
SET
type column #25669 - Fix the data corruption issue in the
IN
expression's arguments #25591 - Avoid the sessions of GC being affected by global variables #24976
- Fix the panic issue that occurs when using
limit
in the window function queries #25344 - Fix the wrong value returned when querying a partitioned table using
Limit
#24636 - Fix the issue that
IFNULL
does not correctly take effect on theENUM
orSET
type column #24944 - Fix the wrong results caused by changing the
count
in the join subqueries tofirst_row
#24865 - Fix the query hang issue that occurs when
ParallelApply
is used under theTopN
operator #24930 - Fix the issue that more results than expected are returned when executing SQL statements using multi-column prefix indexes #24356
- Fix the issue that the
<=>
operator cannot correctly take effect #24477 - Fix the data race issue of the parallel
Apply
operator #23280 - Fix the issue that the
index out of range
error is reported when sorting the IndexMerge results of the PartitionUnion operator #23919 - Fix the issue that setting the
tidb_snapshot
variable to an unexpectedly large value might damage the transaction isolation #25680 - Fix the issue that the ODBC-styled constant (for example,
{d '2020-01-01'}
) cannot be used as the expression #25531 - Fix the issue that
SELECT DISTINCT
converted toBatch Get
causes incorrect results #25320 - Fix the issue that backing off queries from TiFlash to TiKV cannot be triggered #23665 #24421
- Fix the
index-out-of-range
error that occurs when checkingonly_full_group_by
#23839) - Fix the issue that the result of index join in correlated subqueries is wrong #25799
- Fix the issue that an incorrect result is returned when using merge join on the
TiKV
- Fix the wrong
tikv_raftstore_hibernated_peer_state
metric #10330 - Fix the wrong arguments type of the
json_unquote()
function in the coprocessor #10176 - Skip clearing callback during graceful shutdown to avoid breaking ACID in some cases #10353 #10307
- Fix a bug that the read index is shared for replica reads on a Leader #10347
- Fix the wrong function that casts
DOUBLE
toDOUBLE
#25200
- Fix the wrong
PD
- Fix the data race issue that occurs when loading TTL configurations after the scheduler is started #3771
- Fix a bug that the
is_learner
field of theTIKV_REGION_PEERS
table in TiDB is incorrect #3372 #24293 - Fix the issue that when all TiKV nodes in a zone are offline or down, PD does not schedule replicas to other zones #3705
- Fix the issue that PD might get panic after the scatter Region scheduler is added #3762
TiFlash
- Fix the issue that TiFlash keeps restarting because of the split failure
- Fix the potential issue that TiFlash cannot delete the delta data
- Fix a bug that TiFlash adds wrong padding for non-binary characters in the
CAST
function - Fix the issue of incorrect results when handling aggregation queries with complex
GROUP BY
columns - Fix the TiFlash panic issue that occurs under heavy write pressure
- Fix the panic that occurs when the right jon key is not nullalbe and the left join key is nullable
- Fix the potential issue that the
read-index
requests take a long time - Fix the panic issue that occurs when the read load is heavy
- Fix the panic issue that might occur when the
Date_Format
function is called with theSTRING
type argument andNULL
values
Tools
TiCDC
- Fix the issue that TiCDC owner exits when refreshing the checkpoint #1902
- Fix a bug that some MySQL connection might leak after MySQL sink meets the error and pauses #1946
- Fix the panic issue that occurs when TiCDC fails to read
/proc/meminfo
#2024 - Reduce TiCDC's runtime memory consumption #2012 #1958
- Fix a bug that might cause TiCDC server panic due to the late calculation of resolved ts #1576
- Fix the potential deadlock issue for the processor #2142
Backup & Restore (BR)
TiDB Lightning
- Fix the TiDB Lightning panic issue for some special data #1213
- Fix the EOF error reported when TiDB Lightning splits the imported large CSV files #1133
- Fix a bug that an excessively large base value is generated when TiDB Lightning imports tables with the
auto_increment
column of theFLOAT
orDOUBLE
type #1186 - Fix the issue that TiDB fails to parse the
DECIMAL
type data in Parquet files #1277
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