New Features

• [IOTDB-959] Add create storage group Grammar
• [IOTDB-1399] Add a session interface to connect multiple nodes
• [IOTDB-1466] Support device template
• [IOTDB-1491] UDTF query supported in cluster
• [IOTDB-1496] Timed flush memtable
• [IOTDB-1536] Support fuzzy query REGEXP
• [IOTDB-1561] Support fill by specific value
• [IOTDB-1565] Add sql: set system to readonly/writable
• [IOTDB-1569] Timed close TsFileProcessor
• [IOTDB-1586] Support mysql-style Like clause
• [ISSUE-3811] Provide a data type column for the last query dataset
• TTL can be set to the prefix path of storage group
• add JMX monitor to all ThreadPools in the server module

Improvements

• [IOTDB-1566] Do not restrict concurrent write partitions
• [IOTDB-1585] ModificationFile‘s write interface blocking
• [IOTDB-1587] SessionPool optimization: a more aggressive Session creation strategy
• Use StringCachedPool in TsFileResource to reduce the memory size
• write performance optimization when replicaNum == 1
• Optimize Primitive Array Manager
• Function Improvement: add overlapped page rate in Tracing

Bug Fixes

• [IOTDB-1282] fix C++ class SessionDataSet mem-leak
• [IOTDB-1407] fix Filtering time series based on tags query fails Occasionally
• [IOTDB-1437] Fix the TsFileSketchTool NPE
• [IOTDB-1442] Time filter & TTL do not take effect in cluster
• [IOTDB-1452] remove compaction log/ change logger to daily
• [IOTDB-1447] ClientPool is blocking other nodes when one node fails
• [IOTDB-1456] Fix Error occurred while executing delete timeseries statement
• [IOTDB-1461] Fix compaction conflicts with ttl
• [IOTDB-1462] Fix cross space compaction recover null pointer bug
• [IOTDB-1464] fix take byte array null pointer
• [IOTDB-1469] fix cross space compaction lost data bug
• [IOTDB-1471] Fix path not right in "sg may not ready" log
• [IOTDB-1475] MeasurementId check while create timeseries or template/ disable time or timestamp in timeseries path
• [IOTDB-1488] Fix metaMember's forwarding clientPool timeout in cluster module
• [IOTDB-1494] fix compaction block flush bug
• [IoTDB-1499] Remove series registration using IoTDBSink
• [IoTDB-1501] Fix compaction recover delete tsfile bug
• [IOTDB-1529] Fix mlog recover idx bug and synchronize setStorageGroup
• [IOTDB-1537] fix insertTablet permission
• [IOTDB-1539] Fix delete operation with value filter is abnormal
• [IOTDB-1540] Bug Fix: 500 when using IN operator
• [IOTDB-1541] Fix query result not right due to non-precise time index of resource
• [IOTDB-1542] Cpp client segment fault: char[] buffer overflow caused by long exception message
• [IOTDB-1545] Query dataset memory leak on server caused by cpp client
• [IOTDB-1546] Optimize the Upgrade Tool rewrite logic to reduce the temp memory cost
• [IOTDB-1552] Only allow equivalent filter for TEXT data type
• [IOTDB-1556] Abort auto create device when meet exception in setStorageGroup
• [IOTDB-1574] Deleted file handler leak
• [IOTDB-1580] Error result of order by time desc when enable time partition
• [IOTDB-1584] Doesn't support order by time desc in cluster mode
• [IOTDB-1588] Bug fix: MAX_TIME is incorrect in cluster mode
• [IOTDB-1594] Fix show timeseries returns incorrect tag value
• [IOTDB-1600] Fix InsertRowsOfOneDevicePlan being not supported in cluster mode
• [IOTDB-1610] Fix TsFileRewriteTool writing incorrect data file
• [ISSUE-3116] Bug when using natural month unit in time interval in group by query
• [ISSUE-3316] Query result with the same time range is inconsistent in group by query
• [ISSUE-3436] Fix query result not right after deleting multiple time interval of one timeseries
• [ISSUE-3458] fix load configuration does not take effect
• [ISSUE-3545] Fix Time interval value is disorder in group by month
• [ISSUE-3653] fix Max_time and last return inconsistent result
• [ISSUE-3690] Memory leaks on the server when cpp client invokes checkTimeseriesExists
• [ISSUE-3805] OOM caused by Chunk cache
• [ISSUE-3865] Meaningless connection reset issues caused by low default value for SOMAXCONN
• Fix DataMigrationExample OOM if migrate too many timeseries
• Handle false positive cases which may cause NPE of tsfile bloom filter
• Fix Windows shell error on JDK11 & fix iotdb-env.bat not working
• Fix cluster auto create schema bug when retry locally
• Fix thrift out of sequence in cluster module
• Skip non exist measurement in where clause in align by device
• fix blocking query when selecting TsFile in compaction
• Fix redundant data in compaction recover
• Fix load tsfile with time partition enable

Incompatible changes

• [IOTDB-1485] Replace tsfile_size_threshold by unseq_tsfile_size/seq_tsfile_size

Miscellaneous changes

• [IOTDB-1499] Remove unused exception throwing notation in IoTDBSink
• [IOTDB-1500] Remove current dynamic query memory control
• [ISSUE-3674] Disable thrift code generation for Javascript
• enable cacheLeader by default
• add audit log when execute delete and set sg for tracing
• modify nodeTool user to root