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TiDB 4.0.12 Release Notes
Release date: April 2, 2021
TiDB version: 4.0.12
New Features
TiFlash
- Add tools to check the status of
tiflash replica
for online rolling updates
- Add tools to check the status of
Improvements
TiDB
- Refine the output information of the
EXPLAIN
statement for thebatch cop
mode #23164 - Add the warning information for expressions that cannot be pushed to the storage layer in the output of the
EXPLAIN
statement #23020 - Migrate a part of the DDL package code from
Execute
/ExecRestricted
to the safe API (2) #22935 - Migrate a part of the DDL package code from
Execute
/ExecRestricted
to the safe API (1) #22929 - Add
optimization-time
andwait-TS-time
into the slow log #22918 - Support querying
partition_id
from theinfoschema.partitions
table #22489 - Add
last_plan_from_binding
to help the users know whether a SQL statement's execution plan is matched with the hints in the binding #21430 - Scatter truncated tables without the
pre-split
option #22872 - Add three format specifiers for the
str_to_date
expression #22812 - Record the
PREPARE
execution failure asFailed Query OPM
in the metrics monitor #22672 - Do not report errors for the
PREPARE
execution iftidb_snapshot
is set #22641
- Refine the output information of the
TiKV
PD
TiFlash
- Optimize the configuration file and remove useless items
- Reduce the size of TiFlash binary files
- Use an adaptive aggressive GC strategy to reduce memory usage
Tools
TiCDC
Backup & Restore (BR)
- Log the
HTTP_PROXY
andHTTPS_PROXY
environmental variables #827 - Improve the backup performance when there are many tables #745
- Report errors if the service safe point check fails #826
- Add the
cluster_version
andbr_version
information inbackupmeta
#803 - Add retry for external storage errors to increase the success rate of backup #851
- Reduce memory usage during backup #886
- Log the
TiDB Lightning
- Check the TiDB cluster version before running TiDB Lightning to avoid unexpected errors #787
- Fail fast when TiDB Lightning meets the
cancel
error #867 - Add
tikv-importer.engine-mem-cache-size
andtikv-importer.local-writer-mem-cache-size
configuration items to balance between memory usage and performance #866 - Run
batch split region
in parallel for TiDB Lightning's Local-backend to increase the import speed #868 - When using TiDB Lightning to import data from a S3 storage, TiDB Lightning no longer requires the
s3:ListBucket
permission #919 - When resuming from a checkpoint, TiDB Lightning keeps using the original engine #924
Bug Fixes
TiDB
- Fix the issue that the
get
variable expression goes wrong when the session variable is hexadecimal literals#23372 - Fix the issue that wrong collation is used when creating the fast execution plan for the
Enum
orSet
type #23292 - Fix the possible wrong result of the
nullif
expression when it is used withis-null
#23279 - Fix the issue that the auto-analysis is triggered outside its time range #23219
- Fix the issue that the
CAST
function might ignore errors for thepoint get
plan #23211 - Fix a bug that prevents SPM from taking effect when
CurrentDB
is empty #23209 - Fix the issue of possible wrong table filters for the IndexMerge plan #23165
- Fix the issue of unexpected
NotNullFlag
in the returning types of theNULL
constant #23135 - Fix a bug that collation might not be handled by the text type #23092
- Fix the issue that the range partition might incorrectly handle the
IN
expression #23074 - Fix the issue that after marking a TiKV store as tombstone, starting new TiKV stores with different StoreIDs with the same IP address and port keeps returning the
StoreNotMatch
error #23071 - Do not adjust the
INT
type when it isNULL
and compared withYEAR
#22844 - Fix the issue of lost connection when loading data on tables with the
auto_random
column #22736 - Fix the issue of DDL hangover when the DDL operation meets panic in the cancelling path #23297
- Fix the wrong key range of index scan when comparing the
YEAR
column withNULL
#23104 - Fix the issue that a successfully created view is failed to use #23083
- Fix the issue that the
TiKV
PD
- Fix a bug that the isolation level is wrong when the store lacks the label #3474
TiFlash
- Fix the issue of incorrect execution results when the default value of the
binary
type column contains leading or tailing zero bytes - Fix a bug that TiFlash fails to synchronize schema if the name of the database contains special characters
- Fix the issue of incorrect results when handling the
IN
expression with decimal values - Fix a bug that the metric for the opened file count shown in Grafana is high
- Fix a bug that TiFlash does not support the
Timestamp
literal - Fix the potential not responding issue while handling the
FROM_UNIXTIME
expression - Fix the issue of incorrect results when casting string as integer
- Fix a bug that the
like
function might return wrong results
- Fix the issue of incorrect execution results when the default value of the
Tools
TiCDC
- Fix a disorder issue of the
resolved ts
event #1464 - Fix a data loss issue caused by wrong table scheduling due to the network problem #1508
- Fix a bug of untimely release of resources after a processor is stopped #1547
- Fix a bug that the transaction counter is not correctly updated, which might cause database connection leak #1524
- Fix the issue that multiple owners can co-exist when PD has jitter, which might lead to table missing #1540
- Fix a disorder issue of the
Backup & Restore (BR)
TiDB Lightning
- Fix the error that TiKV Importer might ignore that the file has already existed #848
- Fix a bug that the TiDB Lightning might use the wrong timestamp and read the wrong data #850
- Fix a bug that TiDB Lightning's unexpected exit might cause damaged checkpoint file #889
- Fix the issue of possible data error that occurs because the
cancel
error is ignored #874
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