README

Added a "Comparison" section to compare Bolt against other DB options:

1. Relational databases
2. LevelDB
3. LMDB

1 files changed, 44 insertions, 1 deletions

diff --git a/README.md b/README.md
index 727e977..b1501dc 100644
--- a/README.md
+++ b/README.md
@@ -374,7 +374,45 @@ For more information on getting started with Bolt, check out the following artic
 
 
 
-## Comparing Bolt to LMDB
+## Comparison with other databases
+
+### Postgres, MySQL, & other relational databases
+
+Relational databases structure data into rows and are only accessible through
+the use of SQL. This approach provides flexibility in how you store and query
+your data but also incurs overhead in parsing and planning SQL statements. Bolt
+accesses all data by a byte slice key. This makes Bolt fast to read and write
+data by key but provides no built-in support for joining values together.
+
+Most relational databases (with the exception of SQLite) are standalone servers
+that run separately from your application. This gives your systems
+flexibility to connect multiple application servers to a single database
+server but also adds overhead in serializing and transporting data over the
+network. Bolt runs as a library included in your application so all data access
+has to go through your application's process. This brings data closer to your
+application but limits multi-process access to the data.
+
+
+### LevelDB, RocksDB
+
+LevelDB and it's derivatives (RocksDB, HyperLevelDB) are similar to Bolt in that
+they are libraries bundled into the application, however, their underlying
+structure is a log-structured merge-tree (LSM tree). An LSM tree optimizes
+random writes by using a write ahead log and multi-tiered, sorted files called
+SSTables. Bolt uses a B+tree internally and only a single file. Both approaches
+have trade offs.
+
+If you require a high random write throughput (>10,000 w/sec) or you need to use
+spinning disks then LevelDB could be a good choice. If your application is
+read-heavy or does a lot of range scans then Bolt could be a good choice.
+
+One other important consideration is that LevelDB does not have transactions.
+It supports batch writing of key/values pairs and it supports read snapshots
+but it will not give you the ability to do a compare-and-swap operation safely.
+Bolt supports fully serializable ACID transactions.
+
+
+### LDMB
 
 Bolt was originally a port of LMDB so it is architecturally similar. Both use
 a B+tree, have ACID semanetics with fully serializable transactions, and support
@@ -386,6 +424,11 @@ several unsafe actions such as direct writes and append writes for the sake of
 performance. Bolt opts to disallow actions which can leave the database in a 
 corrupted state. The only exception to this in Bolt is `DB.NoSync`.
 
+There are also a few differences in API. LMDB requires a maximum mmap size when
+opening an `mdb_env` whereas Bolt will handle incremental mmap resizing
+automatically. LMDB overloads the getter and setter functions with multiple
+flags whereas Bolt splits these specialized cases into their own functions.
+
 
 ## Caveats & Limitations