Class BDB::Env
In: bdb.rb
Parent: Object

Berkeley DB environment is an encapsulation of one or more databases, log files and shared information about the database environment such as shared memory buffer cache pages.

The simplest way to administer a Berkeley DB application environment is to create a single home directory that stores the files for the applications that will share the environment. The environment home directory must be created before any Berkeley DB applications are run. Berkeley DB itself never creates the environment home directory. The environment can then be identified by the name of that directory.

Methods
begin    checkpoint    close    create    dbremove    dbrename    elect    feedback=    home    lock    lock_detect    lock_id    lock_stat    log_archive    log_archive    log_checkpoint    log_checkpoint    log_curlsn    log_curlsn    log_each    log_each    log_flush    log_flush    log_get    log_get    log_put    log_put    log_reverse_each    log_reverse_each    log_stat    log_stat    new    open    open_db    process_message    recover    remove    rep_elect    rep_process_message    rep_start    set_flags    start    stat    txn_begin    txn_checkpoint    txn_stat    unlink   
Public Class methods
open(home, flags = 0, mode = 0, options = {})

open the Berkeley DB environment

create(home, flags = 0, mode = 0, options = {})

same than open

new(home, flags = 0, mode = 0, options = {})

same than open

remove()

remove the environnement

unlink()

same than remove

Public Instance methods
close()

close the environnement

dbremove(file, database = nil, flags = 0)

only with BDB::VERSION_MAJOR == 4 && BDB::VERSION_MINOR >= 1

remove the database specified by file and database. If no database is nil, the underlying file represented by file is removed, incidentally removing all databases that it contained.

The flags value must be set to 0 or BDB::AUTO_COMMIT

dbrename(file, database, newname, flags = 0)

only with BDB::VERSION_MAJOR == 4 && BDB::VERSION_MINOR >= 1

rename the database specified by file and database to newname. If database is nil, the underlying file represented by file is renamed, incidentally renaming all databases that it contained.

The flags value must be set to 0 or BDB::AUTO_COMMIT

feedback=(proc)

monitor the progress of some operations

home()

return the name of the directory

lock()

Acquire a locker ID

lock_id()

same than lock

lock_detect(type, flags = 0)

The lock_detect function runs one iteration of the deadlock detector. The deadlock detector traverses the lock table, and for each deadlock it finds, marks one of the participating transactions for abort.

type can have one the value BDB::LOCK_OLDEST, BDB::LOCK_RANDOM or BDB::LOCK_YOUNGUEST

flags can have the value BDB::LOCK_CONFLICT, in this case the deadlock detector is run only if a lock conflict has occurred since the last time that the deadlock detector was run.

return the number of transactions aborted by the lock_detect function if BDB::VERSION_MAJOR >= 3 or zero

lock_stat()

Return lock subsystem statistics

log_archive(flags = 0)

The log_archive function return an array of log or database file names.

flags value must be set to 0 or the value BDB::ARCH_DATA, BDB::ARCH_ABS, BDB::ARCH_LOG

log_checkpoint(string)

same as log_put(string, BDB::CHECKPOINT)

log_curlsn(string)

same as log_put(string, BDB::CURLSN)

log_each() {|string, lsn| ...}

Implement an iterator inside of the log

log_flush(string = nil)

same as log_put(string, BDB::FLUSH)

Without argument, garantee that all records are written to the disk

log_get(flag)

The log_get return an array [String, BDB::Lsn] according to the flag value.

flag can has the value BDB::CHECKPOINT, BDB::FIRST, BDB::LAST, BDB::NEXT, BDB::PREV, BDB::CURRENT

log_put(string, flag = 0)

The log_put function appends records to the log. It return an object BDB::Lsn

flag can have the value BDB::CHECKPOINT, BDB::CURLSN, BDB::FLUSH

log_reverse_each() {|string, lsn| ...}

Implement an iterator inside of the log

log_stat()

return log statistics

open_db(type, name = nil, subname = nil, flags = 0, mode = 0)

open the database in the current environment. type must be one of the constant BDB::BTREE, BDB::HASH, BDB::RECNO, BDB::QUEUE. See open for other arguments

recover() {|txn, id| ...}

only with BDB::VERSION_MAJOR == 3 && BDB::VERSION_MINOR >= 3

iterate over all prepared transactions. The transaction txn must be made a call to abort, commit, discard

id is the global transaction ID for the transaction

set_flags(flags, onoff = true)

only with BDB::VERSION_MAJOR == 3 && BDB::VERSION_MINOR >= 2

flags can have the value BDB::CDB_ALLDB, BDB::NOMMAP BDB::TXN_NOSYNC

if onoff is false, the specified flags are cleared

begin(flags = 0)

begin a transaction (the transaction manager must be enabled). flags can have the value DBD::TXN_COMMIT, in this case the transaction will be commited at end.

txn_begin(flags = 0)

same than begin

checkpoint(kbyte, min = 0)

The txn_checkpoint function flushes the underlying memory pool, writes a checkpoint record to the log and then flushes the log.

If either kbyte or min is non-zero, the checkpoint is only done if more than min minutes have passed since the last checkpoint, or if more than kbyte kilobytes of log data have been written since the last checkpoint.

txn_checkpoint(kbyte, min = 0)

same than checkpoint

stat()

Return transaction subsystem statistics

txn_stat()

same than stat

elect(sites, priority, timeout)

Only for DB >= 4

Holds an election for the master of a replication group, returning the new master’s ID

Raise BDB::RepUnavail if the timeout expires

rep_elect(sites, priority, timeout)

same than elect

process_message(control, rec, envid)

Only for DB >= 4

Processes an incoming replication message sent by a member of the replication group to the local database environment

rep_process_message(control, rec, envid)

same than process_message

start(cdata, flags)

Only for DB >= 4

cdata is an identifier flags must be one of BDB::REP_CLIENT, BDB::REP_MASTER or BDB::REP_LOGSONLY

rep_start(cdata, flags)

same than start

log_archive(flags = 0)

The log_archive function return an array of log or database file names.

flags value must be set to 0 or the value BDB::ARCH_DATA BDB::ARCH_DATA, BDB::ARCH_LOG

log_checkpoint(string)

same as log_put(string, BDB::CHECKPOINT)

log_curlsn(string)

same as log_put(string, BDB::CURLSN)

log_each() {|string, lsn| ...}

Implement an iterator inside of the log

log_flush([string])

same as log_put(string, BDB::FLUSH)

Without argument, garantee that all records are written to the disk

log_get(flag)

The log_get return an array [String, BDB::Lsn] according to the flag value.

flag can has the value BDB::CHECKPOINT, BDB::FIRST, BDB::LAST, BDB::NEXT, BDB::PREV, BDB::CURRENT

log_put(string, flag = 0)

The log_put function appends records to the log. It return an object BDB::Lsn

flag can have the value BDB::CHECKPOINT, BDB::CURLSN, BDB::FLUSH

log_reverse_each() {|string, lsn| ...}

Implement an iterator inside of the log

log_stat()

return log statistics