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TiKV Change Log

All notable changes to this project are documented in this file. See also TiDB Changelog and PD Changelog.

[5.0.1] - 2021-04-23

  • Improvements
    • Use zstd to compress the Region snapshot #10005
  • Bug Fixes
    • Fix the issue that the coprocessor fails to properly handle the signed or unsigned integer types in the IN expression #10018
    • Fix the issue of many empty Regions after batch ingesting SST files #10015
    • Fix the potential panic that occurs when the input of cast_string_as_time is invalid UTF-8 bytes #9995
    • Fix a bug that TiKV cannot start up after the file dictionary file is damaged #9992

[5.0.0] - 2021-04-07

  • Compatibility changes
    • Replace the rocksdb.auto-tuned configuration item with rocksdb.rate-limiter-auto-tuned
    • Delete the raftstore.sync-log configuration item. By default, written data is forcibly spilled to the disk. Before v5.0, you can explicitly disable raftstore.sync-log. Since v5.0, the configuration value is forcibly set to true
    • Change the default value of the gc.enable-compaction-filter configuration item from false to true
    • Change the default value of the rate-limiter-auto-tuned configuration item from false to true
  • New features
    • Support log redaction to desensitize the output log information. The configuration item security.redact-info-log. Its default value is false, which means that desensitization is disabled. To enable desensitization for tikv-server logs, set the variable value to true
    • Support transaction async commit
    • Support Raft joint consensus
  • Improvements
    • Enable the system to automatically adjust the data compaction speed by default to balance the contention for I/O resources between background tasks and foreground reads and writes
    • Enable the GC Compaction Filter feature by default to reduce GC’s consumption of CPU and I/O resources

[4.0.12] - 2021-04-02

  • Improvements
  • Prevent a large number of reconnections in a short period of time #9879
  • Optimize the write operations in the scenarios of many tombstones #9729
  • Change the default value of leader-transfer-max-log-lag to 128 to increase the success rate of leader transfer #9605
  • Bug Fixes
  • Fix the issue that the IN expression does not properly handle unsigned/signed integers #9850
  • Fix the issue that the ingest operation is not re-entrant #9779
  • Fix the issue that the space is missed when converting JSON to string in TiKV coprocessor #9666

[4.0.11] - 2021-02-26

  • New Features
    • Support the utf8mb4_unicode_ci collation #9577
    • Support the cast_year_as_time collation #9299
  • Improvements
    • Add metrics of server information for DBaaS #9591
    • Support multiple clusters in Grafana dashboards #9572
    • Report RocksDB metrics to TiDB #9316
    • Record the suspension time for Coprocessor tasks #9277
    • Add thresholds of key counts and key size for Load Base Split #9354
    • Check whether the file exists before data import #9544
    • Improve Fast Tune panels #9180
  • Bug Fixes
    • Fix the issue that TiKV is failed to build with PROST=1 #9604
    • Fix the unmatched memory diagnostics #9589
    • Fix the issue that the end key of a partial RawKV-restore range is inclusive #9583
    • Fix the issue that TiKV might panic when loading the old value of a key of a rolled-back transaction during TiCDC's incremental scan #9569
    • Fix the configuration glitch of old values when changefeeds with different settings connect to one Region #9565
    • Fix a crash issue that occurs when running a TiKV cluster on a machine with a network interface that lacks the MAC address (introduced in v4.0.9) #9516
    • Fix the issue of TiKV OOM when backing up a huge Region #9448
    • Fix the issue that region-split-check-diff cannot be customized #9530
    • Fix the issue of TiKV panic when the system time goes back #9542

[4.0.10] - 2021-01-15

  • Bug Fixes
    • Fix the wrong mapping between ready and peer #9409
    • Fix the issue that some logs are not redacted when security.redact-info-log is set to true #9314

[4.0.9] - 2020-12-18

  • Improvements
    • Add the tag to trace the source of the split command #8936
    • Support dynamically changing the pessimistic-txn.pipelined configuration #9100
    • Reduce the impact on performance when running Backup & Restore and TiDB Lightning #9098
    • Add monitoring metrics for the ingesting SST errors #9096
    • Prevent hibernation when some peers are still catching up with logs #9093
    • Increase the success rate of the pipelined pessimistic locking #9086
    • Change the default value of apply-max-batch-size and store-max-batch-size to 1024 #9020
    • Add the max-background-flushes configuration item #8947
    • Enable the unified read pool for the storage module by default #8887
    • Disable force-consistency-checks by default to improve performance #9029
  • Bug Fixes
    • Fix the issue that Coprocessor might return wrong results when there are more than 255 columns #9131
    • Fix the issue that Region Merge might cause data loss during network partition #9108
    • Fix the issue that the ANALYZE statement might cause panic when using the latin1 character set #9082
    • Fix the wrong results returned when converting the numeric type to the time type #9031
    • Fix a bug that TiDB Lightning fails to ingest SST files to TiKV with the Importer-backend or Local-backend when Transparent Data Encryption (TDE) is enabled #8995
    • Fix the invalid advertise-status-addr value (0.0.0.0) #9036
    • Fix the issue that an error is returned indicating that a key exists when this key is locked and deleted in a committed transaction #8930
    • Fix the issue that the RocksDB cache mapping error causes data corruption #9029
    • Fix a bug that Follower Read might return stale data after the leader is transferred #9240

[4.0.8] - 2020-10-30

  • Improvements
    • Add the Fast-Tune panel page to assist performance diagnostics #8804
    • Add the security.redact-info-log configuration item, which redacts user data from logs #8746
    • Reformat the metafile of error codes #8877
    • Enable dynamically changing the pessimistic-txn.pipelined configuration #8853
    • Enable the memory profiling features by default #8801
  • Bug Fixes
    • Fix the bug that the mutex conflict in encryption causes pd-worker to process heartbeats slowly #8869
    • Fix the issue that the memory profile is mistakenly generated #8790
    • Fix the failure to back up databases on GCS when the storage class is specified #8763
    • Fix the bug that a learner cannot find a leader when the Region is restarted or newly split #8864

[4.0.7] - 2020-09-29

  • Improvements
    • Support the JSON log format #8382
  • Bug Fixes
    • Fix the issue of unavailable Status API when TLS handshake fails #8649
    • Fix the potential undefined behaviors #7782
    • Fix the possible panic caused by generating snapshots when executing UnsafeDestroyRange #8681

[4.0.6] - 2020-09-15

  • Improvements
    • Reduce QPS drop when DropTable or TruncateTable is being executed #8627
    • Support generating metafile of error codes #8619
    • Add performance statistics for cf scan detail #8618
    • Add the rocksdb perf context panel in the Grafana default template #8467
  • Bug Fixes
    • Fix the estimation error for a non-index column when collation is enabled #8620
    • Fix the issue that Green GC might miss locks during the process of Region transfer #8460
    • Fix a panic issue that occurs when TiKV runs very slowly during Raft membership change #8497
    • Fix the deadlock issue that occurs between the PD client thread and other threads when calling PD sync requests #8612
    • Upgrade jemalloc to v5.2.1 to address the issue of memory allocation in huge page #8463
    • Fix the issue that the unified thread pool hangs for long-running queries #8427

[4.0.5] - 2020-08-28

  • New Features
    • Define error code for errors #8387
  • Bug Fixes
    • Speed up leader election when Hibernate Region is enabled #8292
    • Fix the memory leak issue during scheduling #8357
    • Add the hibernate-timeout configuration item to prevent the leader from becoming hibernate too fast #8208

[4.0.3] - 2020-07-24

  • Improvements
    • Introduce the new backup.num-threads configuration to control the size of the backup thread pool #8199
    • Do not send store heartbeats when receiving snapshots #8136
    • Support dynamically changing the shared block cache's capacity #8232
  • Bug Fixes
    • Fix the issue that reads might get stale data during merging #8113
    • Fix the issue that collation does not work on the min/max function when aggregation is pushed down to TiKV #8108

[4.0.2] - 2020-07-01

  • Bug Fixes
    • Fix a memory safety issue for the status server #8101
    • Fix the issue of lost precision in JSON numeric comparison #8087
    • Fix the wrong query slow log #8050
    • Fix the issue that a peer cannot be removed when its store is isolated during multiple merge processes #8048
    • Fix the issue that tikv-ctl recover-mvcc does not remove invalid pessimistic locks #8047
    • Fix the issue that some Titan histogram metrics are missing #7997
    • Fix the issue that TiKV returns duplicated error to TiCDC #7887
  • New Features
    • Support the encryption-meta command in TiKV Control #8103
    • Add a perf context metric for RocksDB::WriteImpl #7991

[4.0.1] - 2020-06-12

  • Bug Fixes
    • Fix the issue that the use-unified-pool configuration in the startup log is incorrectly printed #7946
    • Fix the issue that the tikv-ctl does not support relative path #7963
    • Fix the bug that the monitoring metric of Point Selects is inaccurate #8033
    • Fix the issue that a peer might not be destroyed after the network isolation disappears #8006
    • Fix the issue that a read index request may get out-of-date commit index #8043
    • Improve the reliability of backup and restore with S3 and GCS storages #7917
  • New Features
    • Add the --advertise-status-addr start flag to specify the status address to advertise #8046

[4.0.0] - 2020-05-27

  • Bug Fixes
    • Fix the issue of backup fails with DefaultNotFound error. #7937
    • Tolerate out-of-order read states from raft ready. #7930
    • Handles the case when the callback is dropped by mistake when getting snapshot. #7921
    • Fix the issue that ascii_bin and latin1_bin is not supported by TiKV for new collation framework. #7919
    • Don't clean snapshot files when shutting down. #7927
    • Encryption: fix master key not being able to rotate. #7898
    • Encryption: fix snapshot apply failure caused lock CF snapshot file not being encrypted on received. #7922

[4.0.0-rc.2] - 2020-05-15

  • Compatibility Changes
    • Move the encryption-related configuration to the security-related configuration, which means changing [encryption] in the TiKV configuration file to [security.encryption] #7810
  • New Features
    • Support encryption debugging for tikv-ctl, so that tikv-ctl can be used to operate and manage the cluster when the encryption storage is enabled #7698
    • Support encrypting the lock column family in snapshots #7712
    • Use the heatmap in the Grafana dashboard for Raftstore latency summary to better diagnose the jitter issue #7717
    • Support setting the upper limit for the size of the gRPC message #7824
    • Add in Grafana dashboard the encryption-related monitoring metrics #7827
    • Support Application-Layer Protocol Negotiation (ALPN) #7825
    • Add more statistics about Titan #7818
    • Support using the task ID provided by the client as the identifier in the unified read pool to avoid that the priority of a task is lowered by another task in the same transaction #7814
    • Improve the performance of the batch insert request #7718
  • Bug Fixes
    • Fix the issue that many empty Regions are generated after restoration #7632
    • Fix the panic issue of Raftstore when receiving out-of-order read index responses #7370
    • Fix the issue that an invalid storage or coprocessor read pool configuration might not be rejected when the unified thread pool is enabled #7513
    • Fix the panic issue of the join operation when the TiKV server is shut down #7713
    • Fix the issue that no result is returned when searching TiKV slow logs via diagnostics API #7776
    • Fix the issue that notable memory fragmentation is generated when the TiKV node is running for a long time #7556
    • Fix the issue that the SQL statement fails to execute when an invalid date is stored #7268
    • Fix the issue that the backup data cannot be restored from GCS #7739
    • Fix the issue that KMS key ID is not validated during encryption at rest #7719
    • Fix the underlying correctness issue of the Coprocessor in compilers of different architecture #7714 #7730
    • Fix the snapshot ingestion error when encrytion is enabled #7815
    • Fix the Invalid cross-device link error when rewriting the configuration file [#7817](tikv#7817
    • Fix the issue of wrong toml format when writing the configuration file to an empty file #7817
    • Fix the issue that a destroyed peer in Raftstore can still process requests #7836

[4.0.0-rc.1] - 2020-04-28

  • Compability Changes
    • Disable the Hibernate Region feature by default #7618
  • Important Bug Fixes
    • Fix the deadlock issue caused by the probe request from TiDB #7540
    • Fix the issue that the minimum commit timestamp of a transaction might overflow which affects data correctness #7638
  • New Features
    • Support using the user-owned KMS key for the server-side encryption when backing up data to S3 #7630
    • Enable the load-based split region operation #7623
    • Support validating common names #7468
    • Add the file lock check to avoid starting multiple TiKV instances that are bound to the same address #7447
    • Support AWS KMS in encryption at rest #7465
  • Bug Fixes
    • Address the OpenSSL security issue: CVE-2020-1967 #7622
    • Avoid protecting rollback records written by BatchRollback to improve performance when many write conflicts exist in optimistic transactions #7604
    • Fix the issue that the needless wake-up of transactions results in useless retry and performance reduction in heavy lock-race workloads #7551
    • Fix the issue that the Region might be stuck in the multi-time merging #7518
    • Fix the issue that the learner is not deleted when deleting the learner #7518
    • Fix the issue that follower read might cause panic in raft-rs #7408
    • Fix the bug that a SQL operation might fail because of the group by constant error #7383
    • Fix the issue that an optimistic lock might block reads if the corresponding primary lock is a pessimistic lock #7328

[4.0.0-rc] - 2020-04-08

  • Compatibility Changes
    • Support the pipelined feature in pessimistic transactions, which improves the TPC-C performance by 20%. The risk is that the transaction commit might fail because of lock failure during the execution #6984
    • Enable the unify-read-pool configuration item in new clusters by default and use the previous setting of this item in old clusters #7059
  • New Features
    • Support the pipelined feature in pessimistic transactions, which improves the TPC-C performance by 20%. The risk is that the transaction commit might fail because of lock failure during the execution #6984
    • Support TLS in the HTTP port #5393
    • Enable the unify-read-pool configuration item in new clusters by default and use the previous setting of this item in old clusters #7059
  • Bug Fixes
    • Fix the possible panic caused by transferring the leader when the Follower Read feature is enabled #7101

[4.0.0-beta.2] - 2020-03-18

  • New Features
    • Support the configuration of persistent dynamic update #6684
  • Bugfixes
    • Fix the panic issue caused by empty short values during backup #6718
    • Fix the issue that Hibernate Regions might not be woken up correctly #6772 #6648 #6376

[4.0.0-beta.1] - 2020-02-28

  • Compatibility Changes
  • New Features
    • Support fetching configuration items from the status port via HTTP API #6480
    • Optimize the performance of Chunk Encoder in Coprocessor #6341
  • Bugfixes

[4.0.0-beta] - 2020-01-17

[3.1.0-beta.1] - 2020-01-10

  • backup

    • Change the name of the backup file from start_key to the hash value of start_key to reduce the file name's length for easy reading (tikv#6198)
    • Disable RocksDB's force_consistency_checks check to avoid false positives in the consistency check #6249
    • Add the incremental backup feature #6286

  • sst_importer

    • Fix the issue that the SST file does not have MVCC properties during restoring #6378
    • Add the monitoring items such as tikv_import_download_duration, tikv_import_download_bytes, tikv_import_ingest_duration, tikv_import_ingest_bytes, and tikv_import_error_counter to observe the overheads of downloading and ingesting SST files #6404

  • raftstore

    • Fix the issue of Follower Read that the follower reads stale data when the leader changes, thus breaking transaction isolation #6343

[3.1.0-beta] - 2019-12-18

  • Support the distributed backup and restore feature #5532
  • Support the Follower Read feature #5562

[3.0.20] - 2020-12-25

Bug Fixes

  • Fix the issue that an error is returned indicating that a key exists when this key is locked and deleted in a committed transaction #8931

Improvements

  • Add the end_point_slow_log_threshold configuration item #9145

[3.0.19]

Bugfixes

  • Fix the bug that TiKV panics when parsing responses with missing reason phrases #8540

Improvements

  • Set sync-log to true as an nonadjustable value #8636

[3.0.18]

Misc

  • Change gc failure log to warning #8444

[3.0.17]

Bugfixes

  • Fix a bug that might read stale data during region merging #8111
  • Fix memory leak during scheduling #8355

Improvements

  • Add the hibernate-timeout configuration that delays region hibernation to improve rolling update performance #8207

[3.0.16]

Bugfixes

  • Fix the potential wrong result read from ingested files #8039
  • Fix the issue that a peer can not be removed when its store is isolated during multiple merge processes #8005

Improvements

  • Avoid sending store heartbeats to PD after snapshots are received #8145
  • Improve the PD client log #8091

[3.0.15]

Bugfixes

  • Fix a panic issue that Titan GC may delete an already deleted blob file #7970
  • Fix the issue that clean snapshot files which were in used after restarting #7925
  • Change schedule tick failure log to debug level to make logs less verbose #7904
  • Make grpc message size limit configurable #7822
  • Fix the issue that the memory defragmentation will not be very effective after running for a long time #7790

[3.0.14]

Features

  • Improve the performance when many conflicts and the BatchRollback condition exist in optimistic transactions #7605
  • Fix the issue of decreased performance that occurs because the pessimistic lock waiter is frequently awakened when many conflicts exist in pessimistic transactions #7584

Bugfixes

  • Fix the issue that the node cannot be deleted correctly after the isolation recovery in some cases #7703
  • Fix the issue of data loss during network isolation caused by the Region Merge operation #7679
  • Fix the issue that learner cannot be removed correctly in some cases #7598
  • Fix the issue that the scanning result of raw key-value pairs might be out of order #7597
  • Fix the issue of reconnection when the batch of Raft messages is too large #7542
  • Fix the issue of gRPC thread deadlock caused by the empty request #7538
  • Fix the issue that the processing logic of restarting the learner is incorrect during the merge process #7457
  • Fix the issue that repeated requests on the cleanup of lock might destroy the atomicity of the transaction #7388

[3.0.12]

Bugfixes

  • Fix the issue of conflict detection failure or data index inconsistency caused by inserting an existing key into a transaction and then deleting it immediately when disabling the consistency check parameter #7054
  • Introduce a flow control mechanism in Raftstore to solve the problem that without flow control, it might lead to too slow tracking and cause the cluster to be stuck, and the transaction size might cause frequent reconnection of TiKV connections #7072, #7076

[3.0.11]

Bugfixes

  • Optimize the log output by removing unnecessary logs #6657
  • Fix the panic that might occur when the peer is removed under high loads #6704
  • Fix the issue that Hibernate Regions are not waken up in some cases #6732 #6738

[3.0.10]

  • Raftstore
    • Fix the system panic issue #6460 or data loss issue #5981 caused by Region merge failure #6614
    • Support yield to optimize scheduling fairness, and support pre-transfering the leader to improve leader scheduling stability #6563

[3.0.9] - 2020-01-14

  • Raftstore
    • Speed up the configuration change to speed up the Region scattering #6421
  • Transaction
    • Add the tikv_lock_manager_waiter_lifetime_duration, tikv_lock_manager_detect_duration, and tikv_lock_manager_detect_duration monitoring metrics to monitor waiters’ lifetime, the time cost of detecting deadlocks, and the status of Wait table #6392
    • Optimize the following configuration items to reduce transaction execution latency caused by changing Region leader or the leader of deadlock detector in extreme situations #6429
      • Change the default value of wait-for-lock-time from 3s to 1s
      • Change the default value of wake-up-delay-duration from 100ms to 20ms
    • Fix the issue that the leader of the deadlock detector might be incorrect during the Region Merge process #6431

[3.0.8] - 2019-12-31

  • Coprocessor
    • Modify the level of the output log from error to warn when an error occurs in Coprocessor #6051
    • Modify the update behavior of statistics sampling data from directly updating the row to deleting before inserting, to keep consistency with the update behavior of tidb-server #6069
  • Raftstore
    • Fix the panic caused by repeatedly sending the destroy message to peerfsm and peerfsm being destroyed multiple times #6297
    • Update the default value of split-region-on-table from true to false to disable splitting Regions by table by default #6253
  • Engine
    • Fix the issue that empty data might be returned because RocksDB iterator errors are not correctly processed in extreme conditions #6326
  • Transaction
    • Fix the issue that TiKV fails to write data into keys and GC is blocked because the pessimistic locks are incorrectly cleaned up #6354
    • Optimize the pessimistic lock waiting mechanism to improve the performance in scenarios where the lock conflict is severe #6296
  • Update the default value of tikv_alloc from tikv_alloc/default to jemalloc #6206

[3.0.7] - 2019-12-04

  • Update grpc to fix a potential memory leak issue #6128
  • Deadlock: only observe valid region in order to make sure the manager is in the valid region #6110

[3.0.6] - 2019-11-28

  • Pessimistic Transaction: keep lock's ttl when receive a smaller ttl #6056
  • rust-rocksdb: fix titan options for cf when create cf #6009
  • Fix TiKV panic when aggregation expr type is not valid #6002
  • Pessimistic Transaction: reduce clean up requests in lock_manager #5965
  • Fix a region merge bug which may cause panic: set is_merging flag after restart in raftstore #5892
  • Generate flamegraph at runtime #5961
  • Support to change the config gc io limit dynamically #5957
  • Limit the speed of write for GC #5735
  • Engine: update rocksdb and titan #5968
  • Makefile: add a new rule for CI test #5938
  • Add metrics for commit log duration #5881
  • Pessimistic Transaction: Add support for lock wait timeout #5848
  • LockManager: make has_waiter accurate #5845
  • Fix wrong txn_size when acquire pessimistic lock #5740

[3.0.5] - 2019-10-25

  • Fix the problem that split check is always scanning caused by updating approximate in pd-worker #5716
  • Update rust-rocksdb to avoid intra_L0 compaction issue #5710
  • Fix the bug which may break atomicity: product primary locks of pessimistic transactions from being collapsed #5671
  • Enable rocksdb force_consistency_checks and handle background error #5662
  • Fix the bug in raftstore that painic when getting value encouters an error #5643
  • Fix the bug that do not return the right tso when checking lock #5634
  • Reduce the overhead of region's heartbeat #5620
  • Reduce message flush in raftstore #5617
  • Check Lock's TTL when doing clean up #5589

[3.0.4] - 2019-10-08

  • Fix the issue that the approximate keys is not correct when region is empty #5414
  • Make the config support rocksdb doubly skiplist to optimize reverse-scan #5368
  • Optimize point-get in coprocessor #5463
  • Support batch-split command and empty batch command #5470
  • Fix PointGetter performance issue when there are concurrent write #5495
  • Fix the output on short version flag #5501
  • Support the pessmistic transaction API: txn-heart-beat #5507
  • titan GC and monitoring improvement #5517
  • Update grpcio to v0.4.5 #5523
  • Support GRPC memory quota #5524
  • Fix commit index is not forwarded when merge entry is empty #5526
  • Fix a resource leak bug in batch grpc #5567

[3.0.3] - 2019-08-29

  • Fix the issue that ReadIndex might fail to respond to requests because of duplicate context #5256
  • Fix potential scheduling jitters caused by premature PutStore #5277
  • Fix incorrect timestamps reported from Region heartbeats #5296
  • Fix potential TiKV panics during region merge #5291
  • Speed up leader change check for the dead lock detector #5317
  • Support using grpc env to create deadlock clients #5346
  • Add config-check to check whether the configuration is correct #5349
  • Fix the issue that ReadIndex does not return anything when there is no leader #5351
  • Exclude shared block cache from core dump #5322

[3.0.2] - 2019-08-06

  • Fix the bug that TiKV panics if the Raft Log is not written in time #5160
  • Fix the bug that the panic information is not written into the log file after TiKV panics #5198
  • Fix the bug that the insert operation might be incorrectly performed in the pessimistic transaction #5203
  • Lower the output level of some logs that require no manual intervention to INFO #5193
  • Improve the accuracy of monitoring the storage engine size #5200
  • Improve the accuracy of the Region size in TiKV Control #5195
  • Improve the performance of the deadlock detector for pessimistic locks #5192
  • Improve the performance of GC in the Titan storage engine #5197

[3.0.1] - 2019-06-16

  • Add the statistics of the size of blob files in statistics information #5060
  • Fix the core dump issue caused by the incorrectly cleaned memory resources when the process exits #5053
  • Add all monitoring metrics related to the Titan engine #4772, #4836
  • Add the number of open file handles for Titan when counting the number of open file handles to avoid the issue that no file handle is available because of inaccurate statistics of file handles #5026
  • Set blob_run_mode to decide whether to enable the Titan engine on a specific CF #4991
  • Fix the issue that the read operations cannot get the commit information of pessimistic transactions #5067
  • Add the blob-run-mode configuration parameter to control the running mode of the Titan engine, and its value can be normal, read-only or fallback #4865 Improve the performance of detecting deadlocks #5089

[3.0.0] - 2019-06-28

  • Engine
    • Introduce Titan, a key-value plugin that improves write performance for scenarios with value sizes greater than 1KiB, and relieves write amplification in certain degrees
    • Optimize memory management to reduce memory allocation and copying for Iterator Key Bound Option
    • Support block cache sharing among different column families
  • Server
    • Support reversed raw_scan and raw_batch_scan
    • Support batch receiving and sending Raft messages, improving TPS by 7% for write intensive scenarios
    • Support getting monitoring information via HTTP
    • Support Local Reader in RawKV to improve performance
    • Reduce context switch overhead from batch commands
  • Raftstore
    • Support Multi-thread Raftstore and Multi-thread Apply to improve scalabilities, concurrency capacity, and resource usage within a single node. Performance improves by 70% under the same level of pressure
    • Support checking RocksDB Level 0 files before applying snapshots to avoid write stall
    • Support Hibernate Regions to optimize CPU consumption from RaftStore (Experimental)
    • Remove the local reader thread
  • Transaction
    • Support distributed GC and concurrent lock resolving for improved GC performance
    • Support the pessimistic transaction model (Experimental)
    • Modify the semantics of Insert to allow Prewrite to succeed only when there is no Key
    • Remove txn scheduler
    • Add monitoring items related to read index and GC worker
  • Coprocessor
    • Refactor the computation framework to implement vector operators, computation using vector expressions, and vector aggregations to improve performance
    • Support providing operator execution status for the EXPLAIN ANALYZE statement in TiDB
    • Switch to the work-stealing thread pool model to reduce context switch cost
  • Misc
    • Develop a unified log format specification with restructured log system to facilitate collection and analysis by tools
    • Add performance metrics related to configuration information and key bound crossing.

[3.0.0-rc.3] - 2019-06-21

  • Engine
    • Check iterator status when scanning. 4936
    • Fix the issue that ingested files and directory are not synchronized. 4937
  • Server
    • Sanitize block size configuration. 4928
    • Support replicating the delete_range request without deleting the data when applying. 4490
    • Add read index related metrics. 4830
    • Add GC worker related metrics. 4922
  • Raftstore
    • Fix the issue that local reader cache is not cleared correctly. 4778
    • Fix request latency jetter when transferring leader and conf changes. 4734
    • Remove invalid empty callbacks. 4682
    • Clear stale reads after role change. 4810
    • Synchronize all CF files for the received snapshots. 4807
    • Fix missing fsync calls for snapshots. 4850
  • Coprocessor
    • Improve coprocessor batch executor. 4877
  • Transaction
    • Support ResolveLockLite to allow only resolving specified lock keys. 4882
    • Improve pessimistic lock transaction. 4889
  • Tikv-ctl
    • Improve bad-regions and tombstone subcommands. 4862
  • Misc
    • Add dist_release. 4841

[3.0.0-rc.2] - 2019-05-28

  • Engine
    • Support multiple column families sharing a block cache #4563
  • Server
    • Remove TxnScheduler #4098
    • Support pessimistic lock transactions #4698
  • Raftstore
    • Support hibernate Regions to reduce the consumption of the raftstore CPU #4591
    • Fix the issue that the leader does not reply to the ReadIndex requests for the learner #4653
    • Fix the issue of transferring leader failure in some cases #4684
    • Fix the possible dirty read issue in some cases #4688
    • Fix the issue that a snapshot lacks data in some cases #4716
  • Coprocessor
    • Add more RPN functions
      • LogicalOr #4691
      • LTReal #4602
      • LEReal #4602
      • GTReal #4602
      • GEReal #4602
      • NEReal #4602
      • EQReal #4602
      • IsNull #4720
      • IsTrue #4720
      • IsFalse #4720
      • Support comparison arithmetic for Int #4625
      • Support comparison arithmetic for Decimal #4625
      • Support comparison arithmetic for String #4625
      • Support comparison arithmetic for Time #4625
      • Support comparison arithmetic for Duration #4625
      • Support comparison arithmetic for Json #4625
      • Support plus arithmetic for Int #4733
      • Support plus arithmetic for Real #4733
      • Support plus arithmetic for Decimal #4733
      • Support MOD functions for Int #4727
      • Support MOD functions for Real #4727
      • Support MOD functions for Decimal #4727
      • Support minus arithmetic for Int #4746
      • Support minus arithmetic for Real #4746
      • Support minus arithmetic for Decimal #4746

[3.0.0-rc.1] - 2019-05-10

  • Engine
    • Fix the issue that may cause incorrect statistics on read traffic #4436
    • Fix the issue that may cause prefix extractor panic when deleting a range #4503
    • Optimize memory management to reduce memory allocation and copying for Iterator Key Bound Option #4537
    • Fix the issue that failing to consider learner log gap may in some cases cause panic #4559
    • Support block cache sharing among different column families#4612
  • Server
    • Reduce context switch overhead of batch commands #4473
    • Check the validity of seek iterator status #4470
  • RaftStore
    • Support configurable properties index distance #4517
  • Coprocessor
    • Add batch index scan executor #4419
    • Add vectorized evaluation framework #4322
    • Add execution summary framework for batch executors #4433
    • Check the maximum column when constructing the RPN expression to avoid invalid column offset that may cause evaluation panic #4481
    • Add BatchLimitExecutor #4469
    • Replace the original futures-cpupool with tokio-threadpool in ReadPool to reduce context switch #4486
    • Add batch aggregation framework #4533
    • Add BatchSelectionExecutor #4562
    • Add batch aggression function AVG #4570
    • Add RPN function LogicalAnd#4575
  • Misc
    • Support tcmalloc as a memory allocator #4370

[3.0.0-beta.1] - 2019-03-26

  • Optimize the Coprocessor calculation execution framework and implement the TableScan section, with the Single TableScan performance improved by 5% ~ 30%
    • Implement the definition of the BatchRows row and the BatchColumn column #3660
    • Implement VectorLike to support accessing encoded and decoded data in the same way #4242
    • Define the BatchExecutor to interface and implement the way of converting requests to BatchExecutor #4243
    • Implement transforming the expression tree into the RPN format #4329
    • Implement the BatchTableScanExecutor vectorization calculation operator #4351
  • Unify the log format for easy collection and analysis by tools
  • Support using the Local Reader to read in the Raw Read interface #4222
  • Add metrics about configuration information #4206
  • Add metrics about key exceeding bound #4255
  • Add an option to control panic or return an error when encountering the key exceeding bound error #4254
  • Add support for the INSERT operation, make prewrite succeed only when keys do not exist, and eliminate Batch Get #4085
  • Use more fair batch strategy in the Batch System #4200
  • Support Raw scan in tikv-ctl #3825
  • Support hibernating regions #4591

[3.0.0-beta] - 2019-01-18

  • Support distributed GC #3179
  • Check RocksDB Level 0 files before applying snapshots to avoid Write Stall #3606
  • Support reverse raw_scan and raw_batch_scan #3724
  • Support using HTTP to obtain monitoring information #3855
  • Support DST better #3786
  • Support receiving and sending Raft messages in batch #3913
  • Introduce a new storage engine Titan #3985
  • Upgrade gRPC to v1.17.2 #4023
  • Support receiving the client requests and sending replies in batch #4043
  • Support multi-thread Apply #4044
  • Support multi-thread Raftstore #4066

[2.1.19]

  • Raftstore：Fix the panic occurred when restarting TiKV and is_merging is given an incorrect value in the process of merging Regions and applying the Compact log #5884
  • Importer：Remove the limit on the gRPC message length #5809

[2.1.18]

[2.1.17] - 2019-09-11

  • Fix the incorrect result of counting keys in a Region in some cases #5415
  • Add the config-check option in TiKV to check whether the TiKV configuration item is valid #5391
  • Optimize the starting process to reduce jitters caused by restarting nodes #5277
  • Optimize the resolving locking process in some cases to speed up resolving locking for transactions #5339
  • Optimize the get_txn_commit_info process to speed up committing transactions #5062
  • Simplify Raft-related logs #5425
  • Resolve the issue that TiKV exits abnormally in some cases #5441

[2.1.16] - 2019-08-15

  • Return region error when TiKV is closing #4820
  • Support reverse raw_scan and raw_batch_scan #5148

[2.1.15] - 2019-07-18

  • Unify the log format #5083
  • Improve the accuracy of Region's approximate size or keys in extreme cases to improve the accuracy of scheduling #5085

[2.1.14] - 2019-07-04

  • Optimize processing the empty callback when processing the Raftstore message to avoid sending unnecessary message #4682

[2.1.13] - 2019-06-21

  • Fix the issue that incomplete snapshots are generated in the system caused by the iterator not checking the status #4940
  • Add a feature to check the validity for the block-size configuration #4930

[2.1.12] - 2019-06-13

  • Fix the issue that Regions are not available during the leader transfer process in extreme conditions #4799
  • Fix the issue that TiKV loses data when the power of the machine fails abnormally, caused by delayed data flush to the disk when receiving snapshots #4850

[2.1.11] - 2019-06-03

  • Fix the issue that the learner reads an empty index when there is only one leader and one learner #4751
  • Process ScanLock and ResolveLock in the thread pool with a high priority to reduce their impacts on commands with a normal priority #4791
  • Synchronize all CF files for received snapshots #4811

[2.1.10] - 2019-05-21

  • Reject transfer leader when the region recently changed config #4684
  • Add priority label to coprocessor metrics #4643
  • Fix the issue that read index may read stale data during transfering leader #4724
  • Fix the issue that CommitMerge may cause TiKV unable to restart #4615
  • Fix unknown logs #4730

[2.1.9] - 2019-05-06

  • Fix potential quorum changes when transferring leader (tikv/raft-rs#221)
  • Fix the Importer bug that some SST files fail to be imported but it still returns successful import result #4566
  • Support setting a speed limit in Importer when uploading SST files to TiKV #4607
  • Change Importer RocksDB SST default compression method to lz4 to reduce CPU consumption #4624

[2.1.8] - 2019-04-11

  • Fix the issue of wrong statistics of the read traffic #4441
  • Fix the raftstore performance issue when checking to decide whether to process pending snapshots when many Regions exist #4484
  • Do not ingest files when the number of level 0 SST files exceeds level_zero_slowdown_writes_trigger/2 #4464

[2.1.6] - 2019-03-15

  • Fix the StoreNotMatch issue caused by decoding protobuf error in some cases #4303
  • Improve import speed by increasing default region-split-size to 512 MiB #4347
  • Fix OOM issue by storing the intermediate SST files on disk instead of memory #4348
  • Restrict memory usage by RocksDB #4350
  • Fix the issue that scattering Region doesn't take effect #4352

[2.1.5] - 2019-02-28

  • Fix the panic issue caused by Region merge in some cases #4235
  • Fix the issue that Importer fails to import data in some cases #4223
  • Fix the KeyNotInRegion error in some cases #4125
  • Add the detailed StoreNotMatch error message #3885

[2.1.4] - 2019-02-14

  • Fix the abnormal result issue of the event listener in some cases #4126
  • Fix the duplicate write issue when closing TiKV #4146

[2.1.3] - 2019-01-27

  • Support obtaining the monitoring information using the HTTP method #3855
  • Fix the NULL issue of data_format #4075
  • Add verifying the range for scan requests #4124

[2.1.2] - 2018-12-21

  • Support the configuration format in the unit of DAY (d) and fix the configuration compatibility issue #3931
  • Fix the possible panic issue caused by Approximate Size Split #3942
  • Fix two issues about Region merge #3822, #3873

[2.1.1] - 2018-12-12

  • Avoid transferring the leader to a newly created peer, to optimize the possible delay #3878

[2.1.0] - 2018-11-30

[2.1.0-rc.5] - 2018-11-12

  • Improve the error message of WriteConflict #3750
  • Add the panic mark file #3746
  • Downgrade grpcio to avoid the segment fault issue caused by the new version of gRPC #3650
  • Add the upper limit to the kv_scan interface #3749

[2.1.0-rc.4] - 2018-10-23

  • Optimize the RocksDB Write stall issue caused by applying snapshots #3606
  • Add raftstore tick metrics #3657
  • Upgrade RocksDB and fix the Write block issue and that the source file might be damaged by the Write operation when performing IngestExternalFile #3661
  • Upgrade grpcio and fix the issue that “too many pings” is wrongly reported #3650

[2.1.0-rc.3] - 2018-09-29

Performance

  • Optimize the concurrency for coprocessor requests #3515

New features

  • Add the support for Log functions #3603
  • Add the support for the sha1 function #3612
  • Add the support for the truncate_int function #3532
  • Add the support for the year function #3622
  • Add the support for the truncate_real function #3633

Bug fixes

  • Fix the reporting error behavior related to time functions #3487, #3615
  • Fix the issue that the time parsed from string is inconsistent with that in TiDB #3589

[2.1.0-rc.2] - 2018-09-17

Performance

  • Support splitting Regions based on statistics estimation to reduce the I/O cost #3511
  • Reduce clone in the transaction scheduler #3530

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 by tikv-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

  • Fix the leader election issue caused by discarding the PreVote message of the newly split Region #3557
  • Fix follower related statistics after merging Regions #3573
  • Fix the issue that the local reader uses obsolete Region information #3565
  • Support UnsafeDestroyRange API to speedup garbage data cleaning after table/index has been truncated/dropped #3560

[2.1.0-rc.1] - 2018-08-24

Features

  • Support batch split to avoid too large Regions caused by the Write operation on hot Regions
  • Support splitting Regions based on the number of rows to improve the index scan efficiency

Performance

  • Use LocalReader to separate the Read operation from the raftstore thread to lower the Read latency
  • Refactor the MVCC framework, optimize the memory usage and improve the scan Read performance
  • Support splitting Regions based on statistics estimation to reduce the I/O usage
  • Optimize the issue that the Read performance is affected by continuous Write operations on the rollback record
  • Reduce the memory usage of pushdown aggregation computing

Improvements

  • Add the pushdown support for a large number of built-in functions and better charset support
  • Optimize the GC workflow, improve the GC speed and decrease the impact of GC on the system
  • Enable prevote to speed up service recovery when the network is abnormal
  • Add the related configuration items of RocksDB log files
  • Adjust the default configuration of scheduler_latch
  • Support setting whether to compact the data in the bottom layer of RocksDB when using tikv-ctl to compact data manually
  • Add the check for environment variables when starting TiKV
  • Support dynamically configuring the dynamic_level_bytes parameter based on the existing data
  • Support customizing the log format
  • Integrate tikv-fail in tikv-ctl
  • Add I/O metrics of threads

Bug fixes

  • Fix decimal related issues
  • Fix the issue that gRPC max_send_message_len is set mistakenly
  • Fix the issue caused by misconfiguration of region_size

[2.1.0-beta] - 2018-06-30

Features

  • Upgrade Rust to the nightly-2018-06-14 version
  • Provide a Raft PreVote configuration to avoid leader reelection generated when network recovers after network isolation
  • Add a metric to display the number of files and ingest related information in each layer of RocksDB
  • Print key with too many versions when GC works

Performance

  • Use static metric to optimize multi-label metric performance (YCSB raw get is improved by 3%)
  • Remove box in multiple modules and use patterns to improve the operating performance (YCSB raw get is improved by 3%)
  • Use asynchronous log to improve the performance of writing logs
  • Add a metric to collect the thread status
  • Decease memory copy times by decreasing box used in the application to improve the performance

[2.0.11] - 2019-01-12

  • Fix two issues about Region merge #4003 and #4004

[2.0.10] - 2018-12-16

  • Avoid transferring the leader to a newly created peer, to optimize the possible delay #3929
  • Fix redundant Region heartbeats #3930

[2.0.9] - 2018-11-19

  • Add the end-key limit to the kv_scan interface #3749
  • Abandon the max-tasks-xxx configuration and add max-tasks-per-worker-xxx #3093
  • Fix the CompactFiles issue in RocksDB #3789

[2.0.8] - 2018-10-15

Bug fix

  • Fix the issue that the memory consumed by Raftstore EntryCache keeps increasing when a node goes down 3529

[2.0.7] - 2018-09-17

Improvements

  • Enable dynamic-level-bytes by default to reduce space amplification

Bug Fixes

  • Update Region's approximate size and approximate keys count after Region merge

[2.0.6] 0 - 2018-08-03

Improvements

  • Enlarge scheduler’s default slots to reduce false conflicts
  • Reduce continuous records of rollback transactions, to improve the Read
  • performance when conflicts are extremely severe
  • Limit the size and number of RocksDB log files, to reduce unnecessary
  • disk usage in long-running condition

Bug Fixes

  • Fix the crash issue when converting the data type from string to decimal

[2.0.5] - 2018-07-06

  • Fix the potential overflow issue in decimal operations
  • Fix the dirty read issue that might occur in the process of merge

[2.0.4] - 2018-06-16

Features

  • Add the RocksDB PerfContext interface for debugging
  • Add the region-properties command for tikv-ctl

Improvements

  • Make GC record the log when GC encounters many versions of data
  • Remove the import-mode parameter

Bug Fixes

  • Fix the issue that reverse-seek is slow when many RocksDB tombstones exist
  • Fix the crash issue caused by do_sub

[2.0.3] - 2018-06-01

Bug Fixes

  • Correct wrong peer meta for learners
  • Report an error instead of getting a result if divisor/dividend is 0 in do_div_mod

[2.0.2] - 2018-05-21

Improvements

  • Support configuring more gRPC related parameters
  • Support configuring the timeout range of leader election

Bug Fixes

  • Fix the issue that the Raft log is not printed
  • Fix the issue that obsolete learner is not deleted
  • Fix the issue that the snapshot intermediate file is mistakenly deleted

[2.0.1] - 2018-05-16

Performance

  • Reduced number of thread_yield calls
  • Fix the issue that SELECT FOR UPDATE prevents others from reading

Improvements

  • More verbose logs for slow query
  • Speed up delete range

Bug Fixes

  • Fix the bug that raftstore is accidentally blocked when generating the snapshot
  • Fix the issue that Learner cannot be successfully elected in special conditions
  • Fix the issue that split might cause dirty read in extreme conditions
  • Correct the default value of the read thread pool configuration

[2.0.0] - 2018-04-27

Features

  • Protect critical configuration from incorrect modification
  • Support Region Merge [experimental]
  • Add the Raw DeleteRange API
  • Add the GetMetric API
  • Add Raw Batch Put, Raw Batch Get, Raw Batch Delete and Raw Batch Scan
  • Add Column Family options for the RawKV API and support executing operation on a specific Column Family
  • Support Streaming and Streaming Aggregation in Coprocessor
  • Support configuring the request timeout of Coprocessor
  • Carry timestamps with Region heartbeats
  • Support modifying some RocksDB parameters online, such as block-cache-size
  • Support configuring the behavior of Coprocessor when it encounters some warnings or errors
  • Support starting in the importing data mode to reduce write amplification during the data importing process
  • Support manually splitting Region in halves
  • Improve the data recovery tool tikv-ctl
  • Return more statistics in Coprocessor to guide the behavior of TiDB
  • Support the ImportSST API to import SST files [experimental]
  • Add the TiKV Importer binary to integrate with TiDB Lightning to import data quickly [experimental]

Performance

  • Optimize read performance using ReadPool and increase the raw_get/get/batch_get by 30%
  • Improve metrics performance
  • Inform PD immediately once the Raft snapshot process is completed to speed up balancing
  • Solve performance jitter caused by RocksDB flushing
  • Optimize the space reclaiming mechanism after deleting data
  • Speed up garbage cleaning while starting the server
  • Reduce the I/O overhead during replica migration using DeleteFilesInRanges

Stability

  • Fix the issue that gRPC call does not returned when the PD leader switches
  • Fix the issue that it is slow to offline nodes caused by snapshots
  • Limit the temporary space usage consumed by migrating replicas
  • Report the Regions that cannot elect a leader for a long time
  • Update the Region size information in time according to compaction events
  • Limit the size of scan lock to avoid request timeout
  • Limit the memory usage when receiving snapshots to avoid OOM
  • Increase the speed of CI test
  • Fix the OOM issue caused by too many snapshots
  • Configure keepalive of gRPC
  • Fix the OOM issue caused by an increase of the Region number

[2.0.0-rc6] - 2018-04-19

Improvements

  • Reduce lock contention in Worker
  • Add metrics to the FuturePool

Bug Fixes

  • Fix misused metrics in Coprocessor

[2.0.0-rc.5] - 2018-04-17

New Features

  • Support compacting Regions in tikv-ctl
  • Add raw batch put/get/delete/scan API for TiKV service
  • Add ImportKV service
  • Support eval error in Coprocessor
  • Support dynamic adjustment of RocksDB cache size by tikv-ctl
  • Collect number of rows scanned for each range in Coprocessor
  • Support treating overflow as warning in Coprocessor
  • Support learner in raftstore

Improvements

  • Increase snap GC timeout

[2.0.0-rc.4] - 2018-04-01

New Features

  • Limit the memory usage during receiving snapshots, to avoid OOM in extreme conditions
  • Support configuring the behavior of Coprocessor when it encounters warnings
  • Support importing the data pattern in TiKV
  • Support splitting Region in the middle

Improvements

  • Fix the issue that too many logs are output caused by leader missing when TiKV is isolated
  • Use crossbeam channel in worker

[2.0.0-rc.3] - 2018-03-23

New Features

  • Support Region Merge
  • Add the Raw DeleteRange API
  • Add the GetMetric API
  • Support streaming in Coprocessor
  • Support modifying RocksDB parameters online

Improvements

  • Inform PD immediately once the Raft snapshot process is completed, to speed up balancing
  • Reduce the I/O fluctuation caused by RocksDB sync files
  • Optimize the space reclaiming mechanism after deleting data
  • Improve the data recovery tool tikv-ctl
  • Fix the issue that it is slow to make nodes down caused by snapshot
  • Increase the raw_get/get/batch_get by 30% with ReadPool
  • Support configuring the request timeout of Coprocessor
  • Carry time information in Region heartbeats
  • Limit the space usage of snapshot files to avoid consuming too much disk space
  • Record and report the Regions that cannot elect a leader for a long time
  • Speed up garbage cleaning when starting the server
  • Update the size information about the corresponding Region according to compaction events
  • Limit the size of scan lock to avoid request timeout
  • Use DeleteRange to speed up Region deletion

[2.0.0-rc.2] - 2018-03-15

New Features

  • Implement IngestSST API
  • tikv-ctl now can send consistency-check requests to TiKV
  • Support dumping stats of RocksDB and malloc in tikv-ctl

Improvements

  • Reclaim disk space after data have been deleted

[2.0.0-rc.1] - 2018-03-09

New Features

  • Protect important configuration which cannot be changed after initial configuration
  • Check whether SSD is used when you start the cluster

Improvements

  • Fix the issue that gRPC call is not cancelled when PD leaders switch
  • Optimize the read performance using ReadPool, and improve the performance by 30% for raw get
  • Improve metrics and optimize the usage of metrics

[1.1.0-beta] - 2018-02-24

Improvements

  • Traverse locks using offset + limit to avoid potential GC problems
  • Support resolving locks in batches to improve GC speed
  • Support GC concurrency to improve GC speed
  • Update the Region size using the RocksDB compaction listener for more accurate PD scheduling
  • Delete the outdated data in batches using DeleteFilesInRanges, to make TiKV start faster
  • Configure the Raft snapshot max size to avoid the retained files taking up too much space
  • Support more recovery operations in tikv-ctl
  • Optimize the ordered flow aggregation operation

[1.1.0-alpha] - 2018-01-19

New Features

  • Support Raft learner
  • Support TLS

Improvements

  • Optimize Raft Snapshot and reduce the I/O overhead
  • Optimize the RocksDB configuration to improve performance
  • Optimize count (*) and query performance of unique index in Coprocessor
  • Solve the reconnection issue between PD and TiKV
  • Enhance the features of the data recovery tool tikv-ctl
  • Support the Delete Range feature
  • Support splitting according to table in Regions
  • Support setting the I/O limit caused by snapshot
  • Improve the flow control mechanism

[1.0.8] - 2018-02-11

Improvements

  • Use DeleteFilesInRanges to clear stale data and improve the TiKV starting speed
  • Sync the metadata of the received Snapshot compulsorily to ensure its safety

Bug Fixes

  • Use Decimal in Coprocessor sum

[1.0.7] - 2018-01-22

Improvements

  • Support key-only option in Table Scan executor
  • Support the remote mode in tikv-ctl
  • Fix the loss of scheduling command from PD

Bug Fixes

  • Fix the format compatibility issue of tikv-ctl proto
  • Add timeout in Push metric

[1.0.5] - 2017-12-26

  • Fix the issue that it is slow to get the CPU ID using the get_cpuid function.
  • Support the dynamic-level-bytes parameter to improve the space collection situation.

[1.0.4] - 2017-12-11

  • Fix a possible performance issue when a snapshot is applied
  • Fix the performance issue for reverse scan after removing a lot of data
  • Fix the wrong encoded result for the Decimal type under special circumstances

[1.0.2] - 2017-11-13

  • Support splitting table to ensure one region does not contain data from multiple tables.
  • Limit the length of a key to be no more than 4 KB.
  • More accurate read traffic statistics.
  • Implement deep protection on the coprocessor stack.
  • Fix the LIKE behavior and the do_div_mod bug.

[1.0.1] - 2017-10-30

  • Support flow control with write bytes.
  • Reduce Raft allocation.
  • Increase coprocessor stack size to 10MB.
  • Remove the useless log from coprocessor.

[1.0.0] - 2017-10-15

  • Coprocessor now supports more pushdown functions
  • Support pushing down the sampling operation
  • Support manually triggering data compact to collect space quickly
  • Improve the performance and stability
  • Add a Debug API for debugging