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DESCRIBE
DO
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- Glossary
TiDB 2.1 RC2 Release Notes
On September 14, 2018, TiDB 2.1 RC2 is released. Compared with TiDB 2.1 RC1, this release has great improvement in stability, SQL optimizer, statistics information, and execution engine.
TiDB
- SQL Optimizer
- Put forward a proposal of the next generation Planner #7543
- Improve the optimization rules of constant propagation #7276
- Enhance the computing logic of
Range
to enable it to handle multipleIN
orEQUAL
conditions simultaneously #7577 - Fix the issue that the estimation result of
TableScan
is incorrect whenRange
is empty #7583 - Support the
PointGet
operator for theUPDATE
statement #7586 - Fix the panic issue during the process of executing the
FirstRow
aggregate function in some conditions #7624
- SQL Execution Engine
- Fix the potential
DataRace
issue when theHashJoin
operator encounters an error #7554 - Make the
HashJoin
operator read the inner table and build the hash table simultaneously #7544 - Optimize the performance of Hash aggregate operators #7541
- Optimize the performance of Join operators #7493, #7433
- Fix the issue that the result of
UPDATE JOIN
is incorrect when the Join order is changed #7571 - Improve the performance of Chunk’s iterator #7585
- Fix the potential
- Statistics
- Fix the issue that the auto Analyze work repeatedly analyzes the statistics #7550
- Fix the statistics update error that occurs when there is no statistics change #7530
- Use the RC isolation level and low priority when building
Analyze
requests #7496 - Support enabling statistics auto-analyze on certain period of a day #7570
- Fix the panic issue when logging the statistics information #7588
- Support configuring the number of buckets in the histogram using the
ANALYZE TABLE WITH BUCKETS
statement #7619 - Fix the panic issue when updating an empty histogram #7640
- Update
information_schema.tables.data_length
using the statistics information #7657
- Server
- Add Trace related dependencies #7532
- Enable the
mutex profile
feature of Golang #7512 - The
Admin
statement requires theSuper_priv
privilege #7486 - Forbid users to
Drop
crucial system tables #7471 - Switch from
juju/errors
topkg/errors
#7151 - Complete the functional prototype of SQL Tracing #7016
- Remove the goroutine pool #7564
- Support viewing the goroutine information using the
USER1
signal #7587 - Set the internal SQL to high priority while TiDB is started #7616
- Use different labels to filter internal SQL and user SQL in monitoring metrics #7631
- Store the top 30 slow queries in the last week to the TiDB server #7646
- Put forward a proposal of setting the global system time zone for the TiDB cluster #7656
- Enrich the error message of “GC life time is shorter than transaction duration” #7658
- Set the global system time zone when starting the TiDB cluster #7638
- Compatibility
- Add the unsigned flag for the
Year
type #7542 - Fix the issue of configuring the result length of the
Year
type in thePrepare
/Execute
mode #7525 - Fix the issue of inserting zero timestamp in the
Prepare
/Execute
mode #7506 - Fix the error handling issue of the integer division #7492
- Fix the compatibility issue when processing
ComStmtSendLongData
#7485 - Fix the error handling issue during the process of converting string to integer #7483
- Optimize the accuracy of values in the
information_schema.columns_in_table
table #7463 - Fix the compatibility issue when writing or updating the string type of data using the MariaDB client #7573
- Fix the compatibility issue of aliases of the returned value #7600
- Fix the issue that the
NUMERIC_SCALE
value of the float type is incorrect in theinformation_schema.COLUMNS
table #7602 - Fix the issue that Parser reports an error when the single line comment is empty #7612
- Add the unsigned flag for the
- Expressions
- Check the value of
max_allowed_packet
in theinsert
function #7528 - Support the built-in function
json_contains
#7443 - Support the built-in function
json_contains_path
#7596 - Support the built-in function
encode/decode
#7622 - Fix the issue that some time related functions are not compatible with the MySQL behaviors in some cases #7636
- Fix the compatibility issue of parsing the time type of data in string #7654
- Fix the issue that the time zone is not considered when computing the default value of the
DateTime
data #7655
- Check the value of
- DML
- DDL
- Add the DDL job type and the current schema version information in the monitor #7472
- Complete the design of the
Admin Restore Table
feature #7383 - Fix the issue that the default value of the
Bit
type exceeds 128 #7249 - Fix the issue that the default value of the
Bit
type cannot beNULL
#7604 - Reduce the interval of checking
CREATE TABLE/DATABASE
in the DDL queue #7608 - Use the
ddl/owner/resign
HTTP interface ro release the DDL owner and start electing a new owner #7649
- TiKV Go Client
- Support the issue that the
Seek
operation only obtainsKey
#7419
- Support the issue that the
- Table Partition (Experimental)
PD
- Features
- Improvements
- Optimize the handling process of down stores to make up replicas as soon as possible #1222
- Optimize the start of Coordinator to reduce the unnecessary scheduling caused by restarting PD #1225
- Optimize the memory usage to reduce the overhead caused by heartbeats #1195
- Optimize error handling and improve the log information #1227
- Support querying the Region information of a specific store in pd-ctl #1231
- Support querying the topN Region information based on version comparison in pd-ctl #1233
- Support more accurate TSO decoding in pd-ctl #1242
- Bug fix
- Fix the issue that pd-ctl uses the
hot store
command to exit wrongly #1244
- Fix the issue that pd-ctl uses the
TiKV
- Performance
- Improvements
- Add the pushdown support for a large number of built-in functions
- Add the
leader-transfer-max-log-lag
configuration to fix the failure issue of leader scheduling in specific scenarios #3507 - Add the
max-open-engines
configuration to limit the number of engines opened bytikv-importer
simultaneously #3496 - Limit the cleanup speed of garbage data to reduce the impact on
snapshot apply
#3547 - Broadcast the commit message for crucial Raft messages to avoid unnecessary delay #3592
- Bug fixes
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