Overview

• Simple Relational Database Implemented in Golang
• This code tree is based on Golang ported BusTub RDBMS: go-bustub
  • original code of go-bustub is here

What is Samehada?

• Samehada, which literally means shark skin, is a tool used to grate wasabi, usually for sushi, but also for other Japanese cuisines
• Samehada features its grid shape that forms air bubbles between the grated wasabi, minimizing unnecessary spiciness
• We are proud to call SamehadaDB because the grid produces a pleasant taste and aroma with a nice harmony
• (The text in this section was contributed by ujihisa. Thanks ujihisa)

Current Status

• SamehadaDB can be used as simple embedded DB (library form)
  • Simple Single Page Application Demo (TODO App)
  • Above demo uses SamehadaDB on backend API server
    • Modification for migration from PostgreSQL to SamehadaDB we did
    • All app codes
• ATTENTION: SamehadaDB is not developed for productional use! There are no warranties!
• By the way, procedure described on next section executes almost all defined unit tests except these of taking long time

Procedure of Executing SamehadaDB (executing unit tests)

• Please install golang environment with package system your OS has (apt, yum, brew ...etc)
  • If you use Windows, you can select both Windows native environment and WSL Ubuntu environment
• If you select Windows native environments or golang environment which is installed with package system can't execute SamehadaDB, you should install official binary directly
  • Please refer Download and Install - The Go Programming Language
• Executing all unit tests which test several features and components of SamehadaDB except several tests taking long time
  • $ git clone https://github.com/ryogrid/SamehadaDB.git
  • $ cd SamehadaDB
  • $ go clean -testcache; go test ./... -short -v

Roadmap

Note:
Statuses described berow are of backend and dont't mean supported features of SamehadaDB when you use our DB through frontend.
(now, embeded DB form only exists)

• Predicates on Seq Scan
• Multiple Item on Predicate: AND, OR
• Predicates: <, >, <=, >=
• Null
• Inline types (integer, varchar, float, boolean, bigint, smallint, decimal, timestamp, datetime and etc)
• Delete Tuple
• Update Tuple
  • RESTRICTION: a condition which update transaction aborts on exists
• LIMIT / OFFSET
• Varchar
• Persistent Catalog
• Updating of Table Schema
• LRU replacer
• Latches
• Transactions
• Rollback When Abort Occurs
• Logging
• Checkpointing
  • Simple Checkpointing (all transaction block until finish of checkpointing)
  • Fuzzy Checkpointing (ARIES)
• Recovery from Logs
• Index
  • Hash Index
    • Hash index can be used only equal(==) operator is specified to index having columns
    • When the system exits in not graceful, reconstruction of index data is needed at reboot of system now
  • SkipList Index
  • Tree Based Index
  • Logging/Recovery of Index Data (Redo/Undo)
• JOIN
  • INNER JOIN (Hash Join)
    • Currently, only two tables JOIN is implemented and condition specified at ON clause should be composed of single item
  • CROSS JOIN
• Aggregations (COUNT, MAX, MIN, SUM on SELECT clause including Group by and Having)
• Sort (ORDER BY clause)
• Tuple Level Locking With Strong Strict 2-Phase Locking (SS2PL) Protocol
• Concurrent Execution of Transactions
  • Avoidance of phantom problem is not implemented yet
    • So, current transaction isolation level is "REPEATABLE READ"
  • Retry of txns aborted due to concurrency control protocol is not implemented yet
• Execution Planning from hard coded SQL like method call I/F (like some kind of embedded DB)
• Execution Planning from Query Description text (SQL)
• Frontend Impl as Embedded DB Library (like SQLite)
  • Currently, functions of the library are not thread safe and concurrent transaction is not supported
• Deduplication of Result Records (Distinct)
• Query Optimization
• AS clause (View Management)
• JOIN (more than two tables)
• Nested Query
• DB Connector (Driver) or Other Kind Access Interface
  • Original Protocol
  • MySQL or PostgreSQL Compatible Protocol
  • REST
• Deallocate and Reuse Page
  • Need tracking page usage by BufferPoolManager or TableHeap and need bitmap in header page corresponding to the tracking
• UNION clause
• Eliminate Data Processing with Placing All Scanned Tuples on the Memory
• Communication over SSL/TLS
• Authentication

More Info

• Wiki on this repo

Advisor

• kumagi and more!

Past work

FunnelKVS: Rust implementation of autonomous distributed key-value store which has REST interfaces