TiKV 2.1 GA Release Notes

On November 30, 2018, TiKV 2.1 GA is released. See the following updates in this release. Compared with TiKV 2.0, this release has great improvements in stability, performance, and usability.

Coprocessor

• Add more built-in functions
• Add Coprocessor ReadPool to improve the concurrency in processing the requests
• Fix the time function parsing issue and the time zone related issues
• Optimize the memory usage for pushdown aggregation computing

Transaction

• Optimize the read logic and memory usage of MVCC to improve the performance of the scan operation and the performance of full table scan is 1 time better than that in TiDB 2.0
• Fold the continuous Rollback records to ensure the read performance
• Add the UnsafeDestroyRange API to support to collecting space for the dropping table/index
• Separate the GC module to reduce the impact on write
• Add the upper bound support in the kv_scan command

Raftstore

• Improve the snapshot writing process to avoid RocksDB stall
• Add the LocalReader thread to process read requests and reduce the delay for read requests
• Support BatchSplit to avoid large Region brought by large amounts of write
• Support Region Split according to statistics to reduce the I/O overhead
• Support Region Split according to the number of keys to improve the concurrency of index scan
• Improve the Raft message process to avoid unnecessary delay brought by Region Split
• Enable the PreVote feature by default to reduce the impact of network isolation on services

Storage Engine

• Fix the CompactFilesbug in RocksDB and reduce the impact on importing data using Lightning
• Upgrade RocksDB to v5.15 to fix the possible issue of snapshot file corruption
• Improve IngestExternalFile to avoid the issue that flush could block write

tikv-ctl

• Add the ldb command to diagnose RocksDB related issues
• The compact command supports specifying whether to compact data in the bottommost level