+++ /dev/null
-// Copyright (c) 2015-2016 The btcsuite developers
-// Use of this source code is governed by an ISC
-// license that can be found in the LICENSE file.
-
-/*
-Package database provides a block and metadata storage database.
-
-Overview
-
-As of Feb 2016, there are over 400,000 blocks in the Bitcoin block chain and
-and over 112 million transactions (which turns out to be over 60GB of data).
-This package provides a database layer to store and retrieve this data in a
-simple and efficient manner.
-
-The default backend, ffldb, has a strong focus on speed, efficiency, and
-robustness. It makes use leveldb for the metadata, flat files for block
-storage, and strict checksums in key areas to ensure data integrity.
-
-A quick overview of the features database provides are as follows:
-
- - Key/value metadata store
- - Bitcoin block storage
- - Efficient retrieval of block headers and regions (transactions, scripts, etc)
- - Read-only and read-write transactions with both manual and managed modes
- - Nested buckets
- - Supports registration of backend databases
- - Comprehensive test coverage
-
-Database
-
-The main entry point is the DB interface. It exposes functionality for
-transactional-based access and storage of metadata and block data. It is
-obtained via the Create and Open functions which take a database type string
-that identifies the specific database driver (backend) to use as well as
-arguments specific to the specified driver.
-
-The interface provides facilities for obtaining transactions (the Tx interface)
-that are the basis of all database reads and writes. Unlike some database
-interfaces that support reading and writing without transactions, this interface
-requires transactions even when only reading or writing a single key.
-
-The Begin function provides an unmanaged transaction while the View and Update
-functions provide a managed transaction. These are described in more detail
-below.
-
-Transactions
-
-The Tx interface provides facilities for rolling back or committing changes that
-took place while the transaction was active. It also provides the root metadata
-bucket under which all keys, values, and nested buckets are stored. A
-transaction can either be read-only or read-write and managed or unmanaged.
-
-Managed versus Unmanaged Transactions
-
-A managed transaction is one where the caller provides a function to execute
-within the context of the transaction and the commit or rollback is handled
-automatically depending on whether or not the provided function returns an
-error. Attempting to manually call Rollback or Commit on the managed
-transaction will result in a panic.
-
-An unmanaged transaction, on the other hand, requires the caller to manually
-call Commit or Rollback when they are finished with it. Leaving transactions
-open for long periods of time can have several adverse effects, so it is
-recommended that managed transactions are used instead.
-
-Buckets
-
-The Bucket interface provides the ability to manipulate key/value pairs and
-nested buckets as well as iterate through them.
-
-The Get, Put, and Delete functions work with key/value pairs, while the Bucket,
-CreateBucket, CreateBucketIfNotExists, and DeleteBucket functions work with
-buckets. The ForEach function allows the caller to provide a function to be
-called with each key/value pair and nested bucket in the current bucket.
-
-Metadata Bucket
-
-As discussed above, all of the functions which are used to manipulate key/value
-pairs and nested buckets exist on the Bucket interface. The root metadata
-bucket is the upper-most bucket in which data is stored and is created at the
-same time as the database. Use the Metadata function on the Tx interface
-to retrieve it.
-
-Nested Buckets
-
-The CreateBucket and CreateBucketIfNotExists functions on the Bucket interface
-provide the ability to create an arbitrary number of nested buckets. It is
-a good idea to avoid a lot of buckets with little data in them as it could lead
-to poor page utilization depending on the specific driver in use.
-*/
-package database
OSDN Git Service
