Btree-source-code
=================

A working project for High-concurrency B-tree source code in C.  You probably want to download threadskv10h.c for the latest developement version.

Here are files in the btree source code:

btree2s.c       Single Threaded/MultiProcess version that removes keys all the way back to an original empty btree, placing removed nodes on a free list.  Operates under either memory mapping or file I/O.  Recommended btrees hosted on network file systems.

btree2t.c       Single Threaded/MultiProcess version similar to btree2s except that fcntl locking has been replaced by test & set latches in the first few btree pages.  Uses either memory mapping or file I/O.

btree2u.c		Single Threaded/MultiProcess version that implements a traditional buffer pool manager in the first n pages of the btree file.  The buffer pool accesses its pages with mmap.  Evicted pages are written back to the btree file from the buffer pool pages with pwrite. Recommended for linux.

btree2v.c		Single Threaded/MultiProcess version based on btree2u that utilizes linux only futex calls for latch contention.

threads2h.c     Multi-Threaded/Multi-Process with latching implemented by a latch manager with pthreads/SRW latches in the first few btree pages. Recommended for Windows.

threads2i.c     Multi-Threaded/Multi-Process with latching implemented by a latch manager with test & set latches in the first few btree pages with thread yield system calls during contention.

threads2j.c     Multi-Threaded/Multi-Process with latching implemented by a latch manager with test & set locks in the first few btree pages with Linux futex system calls during contention.

threadskv1.c	Multi-Threaded/Multi-Process based on threads2i.c that generalizes key/value storage in the btree pages. The page slots are reduced to 16 or 32 bits, and the value byte storage occurs along with the key storage.

threadskv2.c	Multi-Threaded/Multi-Process based on threadskv1 that replaces the linear sorted key array with a red/black tree.

threadskv3.c	Multi-Threaded/Multi-Process based on threadskv1 that introduces librarian filler slots in the linear key array to minimize data movement when a new key is inserted into the middle of the array.

threadskv4b.c	Multi-Threaded/Multi-Process based on threadskv3 that manages duplicate keys added to the btree.

threadskv5.c	Multi-Threaded/Multi-Process based on threadskv4b that supports bi-directional cursors through the btree. Also supports raw disk partitions for btrees.

threadskv6.c	Multi-Threaded/Single-Process with traditional buffer pool manager using the swap device.  Based on threadskv5 and btree2u.

threadskv7.c	Multi-Threaded/Single-Process with atomic add of a set of keys under eventual consistency.  Adds an individual key lock manager.

threadskv8.c	Multi-Threaded/Single-Process with atomic-consistent add of a set of keys based on threadskv6.c.  Uses btree page latches as locking granularity.

threadskv10h.c	Multi-Threaded/Multi-Process with 2 Log-Structured-Merge (LSM) btrees based on threadskv8.c. Also adds dual leaf/interior node page sizes for each btree. Note that this file is linux only.

Compilation is achieved on linux or Windows by:

gcc -D STANDALONE -O3 threadskv10g.c -lpthread

or

cl /Ox /D STANDALONE threads2h.c

Please see the project wiki page for additional documentation