New Features

• [IOTDB-68] New shared-nothing cluster
• [IOTDB-507] Add zeppelin-interpreter module
• [IOTDB-825] Aggregation by natural month
• [IOTDB-890] support SDT lossy compression
• [IOTDB-944] Support UDTF (User-defined Timeseries Generating Function)
• [IOTDB-965] Add timeout parameter for query
• [IOTDB-1077] Add insertOneDeviceRecords API in java session
• [IOTDB-1055] Support data compression type GZIP
• [IOTDB-1024] Support multiple aggregated measurements for group by level statement
• [IOTDB-1276] Add explain sql support and remove debug_state parameter
• [IOTDB-1197] Add iotdb-client-go as a git submodule of IoTDB repo
• [IOTDB-1230] Support spans multi time partitions when loading one TsFile
• [IOTDB-1273] Feature/restrucutre python module as well as supporting pandas dataframe
• [IOTDB-1277] support IoTDB as Flink's data source
• [PR-2605] Add level merge to "merge" command

Incompatible changes

• [IOTDB-1081] New TsFile Format
• [ISSUE-2730] Add the number of unseq merge times in TsFile name.

Miscellaneous changes

• [IOTDB-868] Change mlog from txt to bin
• [IOTDB-1069] Restrict the flushing memtable number to avoid OOM when mem_control is disabled
• [IOTDB-1104] Refactor the error handling process of query exceptions
• [IOTDB-1108] Add error log to print file name while error happened
• [IOTDB-1152] Optimize regular data size in traversing
• [IOTDB-1180] Reset the system log file names and maximal disk-space size
• [ISSUE-2515] Set fetchsize through JDBC and Session
• [ISSUE-2598] Throw explicit exception when time series is unknown in where clause
• [PR-2944] Throw exception when device to be queried is not in TsFileMetaData
• [PR-2967] Log memory usage information in SystemInfo for better diagnosis

Bug Fixes

• [IOTDB-1049] Fix NullpointerException and a delete bug in Last query
• [IOTDB-1050] Fix Count timeserise column name is wrong
• [IOTDB-1068] Fix Time series metadata cache bug
• [IOTDB-1084] Fix temporary memory of flushing may cause OOM
• [IOTDB-1106] Fix delete timeseries bug
• [IOTDB-1126] Fix the unseq tsfile delete due to merge
• [IOTDB-1135] Fix the count timeseries prefix path bug
• [IOTDB-1137] Fix MNode.getLeafCount error when existing sub-device
• [ISSUE-2484] Fix creating timeseries error by using "create" or "insert" statement
• [ISSUE-2545, 2549] Fix unseq merge end time bug
• [ISSUE-2611] An unsequence file that covers too many sequence file causes OOM query
• [ISSUE-2688] LRULinkedHashMap does not work as an LRU Cache
• [ISSUE-2709, 1178] Fix cache not cleared after unseq compaction bug, Fix windows 70,10 ci bug in unseq compaction ci
• [ISSUE-2741] getObject method in JDBC should return an Object
• [ISSUE-2746] Fix data overlapped bug after unseq compaction
• [ISSUE-2758] NullPointerException in QueryTimeManager.checkQueryAlive()
• [ISSUE-2905] Fix Files.deleteIfExists() doesn't work for HDFS file
• [ISSUE-2919] Fix C++ client memory leak bug
• [PR-2613] Fix importCSVTool import directory bug & encode bug
• [PR-2409] Fix import csv which can't import time format str
• [PR-2582] Fix sync bug for tsfiles's directory changed by vitural storage group
• [ISSUE-2911] Fix The write stream is not closed when executing the command 'tracing off'