Weekly update in TiDB

Last week, we landed 32 PRs in the TiDB repositories.

Added

• Update the average column size dynamically
• Update statistics using query feedback
• Use tidb_index_lookup_join_currency to control the number of IndexLookupJoin inner workers
• Add a TiDB system variable tidb_hash_join_concurrency
• Make pseudo estimate ratio configurable
• Show memory usage in show processlist

Fixed

• Make inferring of decimal for unix_timestamp more consistent with MySQL
• Fix the bug of writing null value into not null column in write-only state
• Fix the IndexLookUpJoin hang problem
• Update the column’s offset when modifying the column
• Support insert ignore on duplicate update

Improved

• Set explicit_defaults_for_timestamp = on for compatibility with MySQL
• Increase the default lease
• Improve the performance of Clone
• Use a cloned Expression when setting it to plan

Weekly update in TiSpark

Last week, we landed 3 PRs in the TiSpark repositories.

Added

• Add wrapper for Exception handling
• Build a new RPC error handling framework

Weekly update in TiKV and PD

Last week, we landed 25 PRs in the TiKV and PD repositories.

Added

• Support Raft learner in raftstore
• Support adding the learner node
• Modify RocksDB cache size dynamically
• Build tikv-importer as a standalone binary

Fixed

• Remove a misused RocksDB ticker
• Disable DeleteRange by default
• Avoid the panic caused by extreme conditions when generating snapshots
• Fix the issue of allocating IDs frequently

Improved

• Shrink queues into smaller ones to save memory when they are not used anymore
• Simplify the process of ImportSST::Upload API
• Process the overflow_as_warning flag
• Collect the number of rows scanned for each range
• Do not clear taintCache in balanceRegionScheduler
• Adjust the balance configuration
• Add keepalive
• Fix the compatibility issue when adding a new scheduler

New contributors (Thanks!)

• TiKV: Zhang Yuning
• Docs: John Liu
• Docs-cn: yanchaozhong