path: root/dist/api_data.py

# This file is a python script that describes the WiredTiger API.

class Error:
	def __init__(self, name, desc, long_desc=None, **flags):
		self.name = name
		self.desc = desc
		self.long_desc = long_desc
		self.flags = flags

errors = [
	Error('WT_DEADLOCK', 'conflict between concurrent operations', '''
	    This error is generated when an operation cannot be completed
	    due to a conflict with concurrent operations.  The operation
	    may be retried; if a transaction is in progress, it should be
	    rolled back and the operation retried in a new transaction.'''),
	Error('WT_DUPLICATE_KEY', 'attempt to insert an existing key', '''
	    This error is generated when the application attempts to insert
	    a record with the same key as an existing record without the
	    'overwrite' configuration to WT_SESSION::open_cursor.'''),
	Error('WT_ERROR', 'non-specific WiredTiger error', '''
	    This error is returned when an error is not covered by a
	    specific error return.'''),
	Error('WT_NOTFOUND', 'item not found', '''
	    This error indicates an operation did not find a value to
	    return.  This includes cursor search and other operations
	    where no record matched the cursor's search key such as
	    WT_CURSOR::update or WT_CURSOR::remove.'''),
	Error('WT_PANIC', 'WiredTiger library panic', '''
	    This error indicates an underlying problem that requires the
	    application exit and restart.'''),
	Error('WT_RESTART', 'restart the operation (internal)', undoc=True),
]

class Method:
	def __init__(self, config, **flags):
		self.config = config
		self.flags = flags

class Config:
	def __init__(self, name, default, desc, subconfig=None, **flags):
		self.name = name
		self.default = default
		self.desc = desc
		self.subconfig = subconfig
		self.flags = flags

	def __cmp__(self, other):
		return cmp(self.name, other.name)

# All schema objects can have column names (optional for simple tables).
column_meta = [
	Config('columns', '', r'''
	    list of the column names.  Comma-separated list of the form
	    <code>(column[,...])</code>.  For tables, the number of entries
	    must match the total number of values in \c key_format and \c
	    value_format.  For colgroups and indices, all column names must
	    appear in the list of columns for the table''',
	    type='list'),
]

source_meta = [
	Config('source', '', r'''
	    set a custom data source URI for a column group, index or simple
	    table.  By default, the data source URI is derived from the \c
	    type and the column group or index name.  Applications can
	    create tables from existing data sources by supplying a \c
	    source configuration''', undoc=True),
	Config('type', 'file', r'''
	    set the type of data source used to store a column group, index
	    or simple table.  By default, a \c "file:" URI is derived from
	    the object name.  The \c type configuration can be used to
	    switch to a different data source, such as LSM or an extension
	    configured by the application.'''),
]

format_meta = column_meta + [
	Config('key_format', 'u', r'''
	    the format of the data packed into key items.  See @ref
	    schema_format_types for details.  By default, the key_format is
	    \c 'u' and applications use WT_ITEM structures to manipulate
	    raw byte arrays. By default, records are stored in row-store
	    files: keys of type \c 'r' are record numbers and records
	    referenced by record number are stored in column-store files''',
	    type='format'),
	Config('value_format', 'u', r'''
	    the format of the data packed into value items.  See @ref
	    schema_format_types for details.  By default, the value_format
	    is \c 'u' and applications use a WT_ITEM structure to
	    manipulate raw byte arrays. Value items of type 't' are
	    bitfields, and when configured with record number type keys,
	    will be stored using a fixed-length store''',
	    type='format'),
]

lsm_config = [
	Config('lsm', '', r'''
	    options only relevant for LSM data sources''',
	    type='category', subconfig=[
	    Config('auto_throttle', 'true', r'''
	        Throttle inserts into LSM trees if flushing to disk isn't
	        keeping up''',
	        type='boolean'),
	    Config('bloom', 'true', r'''
	        create bloom filters on LSM tree chunks as they are merged''',
	        type='boolean'),
	    Config('bloom_config', '', r'''
	        config string used when creating Bloom filter files, passed
	        to WT_SESSION::create'''),
	    Config('bloom_bit_count', '16', r'''
	        the number of bits used per item for LSM bloom filters''',
	        min='2', max='1000'),
	    Config('bloom_hash_count', '8', r'''
	        the number of hash values per item used for LSM bloom
	        filters''',
	        min='2', max='100'),
	    Config('bloom_oldest', 'false', r'''
	        create a bloom filter on the oldest LSM tree chunk. Only
	        supported if bloom filters are enabled''',
	        type='boolean'),
	    Config('chunk_max', '5GB', r'''
	        the maximum size a single chunk can be. Chunks larger than this
	        size are not considered for further merges. This is a soft
	        limit, and chunks larger than this value can be created.  Must
	        be larger than chunk_size''',
	        min='100MB', max='10TB'),
	    Config('chunk_size', '10MB', r'''
	        the maximum size of the in-memory chunk of an LSM tree.  This
	        limit is soft - it is possible for chunks to be temporarily
	        larger than this value.  This overrides the \c memory_page_max
	        setting''',
	        min='512K', max='500MB'),
	    Config('merge_max', '15', r'''
	        the maximum number of chunks to include in a merge operation''',
	        min='2', max='100'),
	    Config('merge_min', '0', r'''
	        the minimum number of chunks to include in a merge operation. If
	        set to 0 or 1 half the value of merge_max is used''',
	        max='100'),
	    Config('merge_threads', '2', r'''
	        the number of threads to perform merge operations''',
	        min='1', max='10'), # !!! max must match WT_LSM_MAX_WORKERS
	]),
]

# Per-file configuration
file_config = format_meta + [
	Config('block_allocation', 'best', r'''
	    configure block allocation. Permitted values are \c "first" or
	    \c "best"; the \c "first" configuration uses a first-available
	    algorithm during block allocation, the \c "best" configuration
	    uses a best-fit algorithm''',
	    choices=['first', 'best',]),
	Config('allocation_size', '4KB', r'''
	    the file unit allocation size, in bytes, must a power-of-two;
	    smaller values decrease the file space required by overflow
	    items, and the default value of 4KB is a good choice absent
	    requirements from the operating system or storage device''',
	    min='512B', max='128MB'),
	Config('block_compressor', '', r'''
	    configure a compressor for file blocks.  Permitted values are
	    empty (off) or \c "bzip2", \c "snappy" or custom compression
	    engine \c "name" created with WT_CONNECTION::add_compressor.
	    See @ref compression for more information'''),
	Config('cache_resident', 'false', r'''
	    do not ever evict the object's pages; see @ref
	    tuning_cache_resident for more information''',
	    type='boolean'),
	Config('checksum', 'uncompressed', r'''
	    configure block checksums; permitted values are <code>on</code>
	    (checksum all blocks), <code>off</code> (checksum no blocks) and
	    <code>uncompresssed</code> (checksum only blocks which are not
	    compressed for any reason).  The \c uncompressed setting is for
	    applications which can rely on decompression to fail if a block
	    has been corrupted''',
	    choices=['on', 'off', 'uncompressed']),
	Config('collator', '', r'''
	    configure custom collation for keys.  Value must be a collator
	    name created with WT_CONNECTION::add_collator'''),
	Config('dictionary', '0', r'''
	    the maximum number of unique values remembered in the Btree
	    row-store leaf page value dictionary; see
	    @ref file_formats_compression for more information''',
	    min='0'),
	Config('format', 'btree', r'''
	    the file format''',
	    choices=['btree']),
	Config('huffman_key', '', r'''
	    configure Huffman encoding for keys.  Permitted values
	    are empty (off), \c "english", \c "utf8<file>" or \c
	    "utf16<file>".  See @ref huffman for more information'''),
	Config('huffman_value', '', r'''
	    configure Huffman encoding for values.  Permitted values
	    are empty (off), \c "english", \c "utf8<file>" or \c
	    "utf16<file>".  See @ref huffman for more information'''),
	Config('internal_key_truncate', 'true', r'''
	    configure internal key truncation, discarding unnecessary
	    trailing bytes on internal keys (ignored for custom
	    collators)''',
	    type='boolean'),
	Config('internal_page_max', '4KB', r'''
	    the maximum page size for internal nodes, in bytes; the size
	    must be a multiple of the allocation size and is significant
	    for applications wanting to avoid excessive L2 cache misses
	    while searching the tree.  The page maximum is the bytes of
	    uncompressed data, that is, the limit is applied before any
	    block compression is done''',
	    min='512B', max='512MB'),
	Config('internal_item_max', '0', r'''
	    the largest key stored within an internal node, in bytes.  If
	    non-zero, any key larger than the specified size will be
	    stored as an overflow item (which may require additional I/O
	    to access).  If zero, a default size is chosen that permits at
	    least 8 keys per internal page''',
	    min=0),
	Config('key_gap', '10', r'''
	    the maximum gap between instantiated keys in a Btree leaf page,
	    constraining the number of keys processed to instantiate a
	    random Btree leaf page key''',
	    min='0', undoc=True),
	Config('leaf_page_max', '1MB', r'''
	    the maximum page size for leaf nodes, in bytes; the size must
	    be a multiple of the allocation size, and is significant for
	    applications wanting to maximize sequential data transfer from
	    a storage device.  The page maximum is the bytes of uncompressed
	    data, that is, the limit is applied before any block compression
	    is done''',
	    min='512B', max='512MB'),
	Config('leaf_item_max', '0', r'''
	    the largest key or value stored within a leaf node, in bytes.
	    If non-zero, any key or value larger than the specified size
	    will be stored as an overflow item (which may require additional
	    I/O to access).  If zero, a default size is chosen that permits
	    at least 4 key and value pairs per leaf page''',
	    min=0),
	Config('memory_page_max', '5MB', r'''
	    the maximum size a page can grow to in memory before being
	    reconciled to disk.  The specified size will be adjusted to a lower
	    bound of <code>50 * leaf_page_max</code>.  This limit is soft - it
	    is possible for pages to be temporarily larger than this value.
	    This setting is ignored for LSM trees, see \c chunk_size''',
	    min='512B', max='10TB'),
	Config('os_cache_max', '0', r'''
	    maximum system buffer cache usage, in bytes.  If non-zero, evict
	    object blocks from the system buffer cache after that many bytes
	    from this object are read or written into the buffer cache''',
	    min=0),
	Config('os_cache_dirty_max', '0', r'''
	    maximum dirty system buffer cache usage, in bytes.  If non-zero,
	    schedule writes for dirty blocks belonging to this object in the
	    system buffer cache after that many bytes from this object are
	    written into the buffer cache''',
	    min=0),
	Config('prefix_compression', 'true', r'''
	    configure prefix compression on row-store leaf pages''',
	    type='boolean'),
	Config('prefix_compression_min', '4', r'''
	    minimum gain before prefix compression will be used on row-store
	    leaf pages''',
	    min=0),
	Config('split_pct', '75', r'''
	    the Btree page split size as a percentage of the maximum Btree
	    page size, that is, when a Btree page is split, it will be
	    split into smaller pages, where each page is the specified
	    percentage of the maximum Btree page size''',
	    min='25', max='100'),
]

# File metadata, including both configurable and non-configurable (internal)
file_meta = file_config + [
	Config('checkpoint', '', r'''
	    the file checkpoint entries'''),
	Config('checkpoint_lsn', '', r'''
	    LSN of the last checkpoint'''),
	Config('id', '', r'''
	    the file's ID number'''),
	Config('version', '(major=0,minor=0)', r'''
	    the file version'''),
]

table_only_meta = [
	Config('colgroups', '', r'''
	    comma-separated list of names of column groups.  Each column
	    group is stored separately, keyed by the primary key of the
	    table.  If no column groups are specified, all columns are
	    stored together in a single file.  All value columns in the
	    table must appear in at least one column group.  Each column
	    group must be created with a separate call to
	    WT_SESSION::create''', type='list'),
]

colgroup_meta = column_meta + source_meta

index_meta = format_meta + source_meta

table_meta = format_meta + table_only_meta

# Connection runtime config, shared by conn.reconfigure and wiredtiger_open
connection_runtime_config = [
	Config('shared_cache', '', r'''
	    shared cache configuration options. A database should configure
	    either a cache_size or a shared_cache not both''',
	    type='category', subconfig=[
	    Config('enable', 'false', r'''
	        whether the connection is using a shared cache''',
	        type='boolean'),
	    Config('chunk', '10MB', r'''
	        the granularity that a shared cache is redistributed''',
	        min='1MB', max='10TB'),
	    Config('reserve', '0', r'''
	        amount of cache this database is guaranteed to have
	        available from the shared cache. This setting is per
	        database. Defaults to the chunk size''', type='int'),
	    Config('name', 'pool', r'''
	        name of a cache that is shared between databases'''),
	    Config('size', '500MB', r'''
	        maximum memory to allocate for the shared cache. Setting
	        this will update the value if one is already set''',
	        min='1MB', max='10TB')
	    ]),
	Config('cache_size', '100MB', r'''
	    maximum heap memory to allocate for the cache. A database should
	    configure either a cache_size or a shared_cache not both''',
	    min='1MB', max='10TB'),
	Config('error_prefix', '', r'''
	    prefix string for error messages'''),
	Config('eviction_dirty_target', '80', r'''
	    continue evicting until the cache has less dirty pages than this
	    (as a percentage). Dirty pages will only be evicted if the cache
	    is full enough to trigger eviction''',
	    min=10, max=99),
	Config('eviction_target', '80', r'''
	    continue evicting until the cache becomes less full than this
	    (as a percentage).    Must be less than \c eviction_trigger''',
	    min=10, max=99),
	Config('eviction_trigger', '95', r'''
	    trigger eviction when the cache becomes this full (as a
	    percentage)''',
	    min=10, max=99),
	Config('statistics', 'none', r'''
	    Maintain database statistics, which may impact performance.
	    Choosing "all" maintains all statistics regardless of cost,
	    "fast" maintains a subset of statistics that are relatively
	    inexpensive, "none" turns off all statistics.  The "clear"
	    configuration resets statistics after they are gathered,
	    where appropriate (for example, a cache size statistic is
	    not cleared, while the count of cursor insert operations will
	    be cleared).   When "clear" is configured for the database,
	    gathered statistics are reset each time a statistics cursor
	    is used to gather statistics, as well as each time statistics
	    are logged using the \c statistics_log configuration.  See
	    @ref statistics for more information''',
	    type='list', choices=['all', 'fast', 'none', 'clear']),
	Config('verbose', '', r'''
	    enable messages for various events.  Options are given as a
	    list, such as <code>"verbose=[evictserver,read]"</code>''',
	    type='list', choices=[
	        'block',
	        'ckpt',
	        'compact',
	        'evict',
	        'evictserver',
	        'fileops',
	        'hazard',
	        'log',
	        'lsm',
	        'mutex',
	        'overflow',
	        'read',
	        'readserver',
	        'reconcile',
	        'recovery',
	        'salvage',
	        'shared_cache',
	        'verify',
	        'version',
	        'write']),
]

session_config = [
	Config('isolation', 'read-committed', r'''
	    the default isolation level for operations in this session''',
	    choices=['read-uncommitted', 'read-committed', 'snapshot']),
]

methods = {
'file.meta' : Method(file_meta),

'colgroup.meta' : Method(colgroup_meta),

'index.meta' : Method(index_meta),

'table.meta' : Method(table_meta),

'cursor.close' : Method([]),

'session.close' : Method([]),

'session.compact' : Method([
	Config('timeout', '1200', r'''
	    maximum amount of time to allow for compact in seconds. The
	    actual amount of time spent in compact may exceed the configured
	    value. A value of zero disables the timeout''',
	    type='int'),
]),

'session.create' :
	    Method(table_only_meta + file_config + lsm_config + source_meta + [
	Config('exclusive', 'false', r'''
	    fail if the object exists.  When false (the default), if the
	    object exists, check that its settings match the specified
	    configuration''',
	    type='boolean'),
]),

'session.drop' : Method([
	Config('force', 'false', r'''
	    return success if the object does not exist''',
	    type='boolean'),
	Config('remove_files', 'true', r'''
	    should the underlying files be removed?''',
	    type='boolean'),
]),

'session.log_printf' : Method([]),

'session.open_cursor' : Method([
	Config('append', 'false', r'''
	    append the value as a new record, creating a new record
	    number key; valid only for cursors with record number keys''',
	    type='boolean'),
	Config('bulk', 'false', r'''
	    configure the cursor for bulk-loading, a fast, initial load
	    path (see @ref bulk_load for more information).  Bulk-load
	    may only be used for newly created objects and cursors
	    configured for bulk-load only support the WT_CURSOR::insert
	    and WT_CURSOR::close methods.  When bulk-loading row-store
	    objects, keys must be loaded in sorted order.  The value is
	    usually a true/false flag; when bulk-loading fixed-length
	    column store objects, the special value \c bitmap allows
	    chunks of a memory resident bitmap to be loaded directly into
	    a file by passing a \c WT_ITEM to WT_CURSOR::set_value where
	    the \c size field indicates the number of records in the
	    bitmap (as specified by the object's \c value_format
	    configuration). Bulk-loaded bitmap values must end on a byte
	    boundary relative to the bit count (except for the last set
	    of values loaded)'''),
	Config('checkpoint', '', r'''
	    the name of a checkpoint to open (the reserved name
	    "WiredTigerCheckpoint" opens the most recent internal
	    checkpoint taken for the object).  The cursor does not
	    support data modification'''),
	Config('dump', '', r'''
	    configure the cursor for dump format inputs and outputs:
	    "hex" selects a simple hexadecimal format, "print"
	    selects a format where only non-printing characters are
	    hexadecimal encoded.  The cursor dump format is compatible
	    with the @ref util_dump and @ref util_load commands''',
	    choices=['hex', 'print']),
	Config('next_random', 'false', r'''
	    configure the cursor to return a pseudo-random record from
	    the object; valid only for row-store cursors.  Cursors
	    configured with \c next_random=true only support the
	    WT_CURSOR::next and WT_CURSOR::close methods.  See @ref
	    cursor_random for details''',
	    type='boolean'),
	Config('overwrite', 'true', r'''
	    configures whether the cursor's insert, update and remove
	    methods check the existing state of the record.  If \c overwrite
	    is \c false, WT_CURSOR::insert fails with ::WT_DUPLICATE_KEY
	    if the record exists, WT_CURSOR::update and WT_CURSOR::remove
	    fail with ::WT_NOTFOUND if the record does not exist''',
	    type='boolean'),
	Config('raw', 'false', r'''
	    ignore the encodings for the key and value, manage data as if
	    the formats were \c "u".  See @ref cursor_raw for details''',
	    type='boolean'),
	Config('statistics', '', r'''
	    Specify the statistics to be gathered.  Choosing "all" gathers
	    statistics regardless of cost and may include traversing
	    on-disk files; "fast" gathers a subset of relatively
	    inexpensive statistics.  The selection must agree with the
	    database \c statistics configuration specified to
	    ::wiredtiger_open or WT_CONNECTION::reconfigure.  For example,
	    "all" or "fast" can be configured when the database is
	    configured with "all", but the cursor open will fail if "all"
	    is specified when the database is configured with "fast",
	    and the cursor open will fail in all cases when the database
	    is configured with "none".  If \c statistics is not configured,
	    the default configuration is the database configuration.
	    The "clear" configuration resets statistics after gathering
	    them, where appropriate (for example, a cache size statistic
	    is not cleared, while the count of cursor insert operations
	    will be cleared).  See @ref statistics for more information''',
	    type='list', choices=['all', 'fast', 'clear']),
	Config('target', '', r'''
	    if non-empty, backup the list of objects; valid only for a
	    backup data source''',
	    type='list'),
]),

'session.rename' : Method([]),
'session.salvage' : Method([
	Config('force', 'false', r'''
	    force salvage even of files that do not appear to be WiredTiger
	    files''',
	    type='boolean'),
]),
'session.truncate' : Method([]),
'session.upgrade' : Method([]),
'session.verify' : Method([
	Config('dump_address', 'false', r'''
	    Display addresses and page types as pages are verified, using
	    the application's message handler, intended for debugging''',
	    type='boolean'),
	Config('dump_blocks', 'false', r'''
	    Display the contents of on-disk blocks as they are verified, using
	    the application's message handler, intended for debugging''',
	    type='boolean'),
	Config('dump_pages', 'false', r'''
	    Display the contents of in-memory pages as they are verified, using
	    the application's message handler, intended for debugging''',
	    type='boolean')
]),

'session.begin_transaction' : Method([
	Config('isolation', '', r'''
	    the isolation level for this transaction; defaults to the
	    session's isolation level''',
	    choices=['read-uncommitted', 'read-committed', 'snapshot']),
	Config('name', '', r'''
	    name of the transaction for tracing and debugging'''),
	Config('priority', 0, r'''
	    priority of the transaction for resolving conflicts.
	    Transactions with higher values are less likely to abort''',
	    min='-100', max='100'),
]),

'session.commit_transaction' : Method([]),
'session.rollback_transaction' : Method([]),

'session.checkpoint' : Method([
	Config('drop', '', r'''
	    specify a list of checkpoints to drop.
	    The list may additionally contain one of the following keys:
	    \c "from=all" to drop all checkpoints,
	    \c "from=<checkpoint>" to drop all checkpoints after and
	    including the named checkpoint, or
	    \c "to=<checkpoint>" to drop all checkpoints before and
	    including the named checkpoint.  Checkpoints cannot be
	    dropped while a hot backup is in progress or if open in
	    a cursor''', type='list'),
	Config('force', 'false', r'''
	    by default, checkpoints may be skipped if the underlying object
	    has not been modified, this option forces the checkpoint''',
	    type='boolean'),
	Config('name', '', r'''
	    if non-empty, specify a name for the checkpoint (note that
	    checkpoints including LSM trees may not be named)'''),
	Config('target', '', r'''
	    if non-empty, checkpoint the list of objects''', type='list'),
]),

'connection.add_collator' : Method([]),
'connection.add_compressor' : Method([]),
'connection.add_data_source' : Method([]),
'connection.add_extractor' : Method([]),
'connection.close' : Method([]),
'connection.reconfigure' : Method(connection_runtime_config),

'connection.load_extension' : Method([
	Config('config', '', r'''
	    configuration string passed to the entry point of the
	    extension as its WT_CONFIG_ARG argument'''),
	Config('entry', 'wiredtiger_extension_init', r'''
	    the entry point of the extension, called to initialize the
	    extension when it is loaded.  The signature of the function
	    must match ::wiredtiger_extension_init'''),
	Config('terminate', 'wiredtiger_extension_terminate', r'''
	    an optional function in the extension that is called before
	    the extension is unloaded during WT_CONNECTION::close.  The
	    signature of the function must match
	    ::wiredtiger_extension_terminate'''),
]),

'connection.open_session' : Method(session_config),

'session.reconfigure' : Method(session_config),

'wiredtiger_open' : Method(connection_runtime_config + [
	Config('buffer_alignment', '-1', r'''
	    in-memory alignment (in bytes) for buffers used for I/O.  The
	    default value of -1 indicates a platform-specific alignment
	    value should be used (4KB on Linux systems, zero elsewhere)''',
	    min='-1', max='1MB'),
	Config('checkpoint', '', r'''
	    periodically checkpoint the database''',
	    type='category', subconfig=[
	    Config('name', '"WiredTigerCheckpoint"', r'''
	        the checkpoint name'''),
	    Config('wait', '0', r'''
	        seconds to wait between each checkpoint; setting this value
	        configures periodic checkpoints''',
	        min='1', max='100000'),
	    ]),
	Config('checkpoint_sync', 'true', r'''
	    flush files to stable storage when closing or writing
	    checkpoints''',
	    type='boolean'),
	Config('create', 'false', r'''
	    create the database if it does not exist''',
	    type='boolean'),
	Config('direct_io', '', r'''
	    Use \c O_DIRECT to access files.  Options are given as a list,
	    such as <code>"direct_io=[data]"</code>.  Configuring
	    \c direct_io requires care, see @ref
	    tuning_system_buffer_cache_direct_io for important warnings''',
	    type='list', choices=['checkpoint', 'data', 'log']),
	Config('extensions', '', r'''
	    list of shared library extensions to load (using dlopen).
	    Any values specified to an library extension are passed to
	    WT_CONNECTION::load_extension as the \c config parameter
	    (for example,
	    <code>extensions=(/path/ext.so={entry=my_entry})</code>)''',
	    type='list'),
	Config('file_extend', '', r'''
	    file extension configuration.  If set, extend files of the set
	    type in allocations of the set size, instead of a block at a
	    time as each new block is written.  For example,
	    <code>file_extend=(data=16MB)</code>''',
	    type='list', choices=['data', 'log']),
	Config('hazard_max', '1000', r'''
	    maximum number of simultaneous hazard pointers per session
	    handle''',
	    min='15'),
	Config('log', '', r'''
	    enable logging''',
	    type='category', subconfig=[
	    Config('archive', 'true', r'''
	        automatically archive unneeded log files''',
	        type='boolean'),
	    Config('enabled', 'false', r'''
	        enable logging subsystem''',
	        type='boolean'),
	    Config('file_max', '100MB', r'''
	        the maximum size of log files''',
	        min='100KB', max='2GB'),
	    Config('path', '""', r'''
	        the path to a directory into which the log files are written.
	        If the value is not an absolute path name, the files are created
	        relative to the database home'''),
	    ]),
	Config('lsm_merge', 'true', r'''
	    merge LSM chunks where possible''',
	    type='boolean'),
	Config('mmap', 'true', r'''
	    Use memory mapping to access files when possible''',
	    type='boolean'),
	Config('multiprocess', 'false', r'''
	    permit sharing between processes (will automatically start an
	    RPC server for primary processes and use RPC for secondary
	    processes). <b>Not yet supported in WiredTiger</b>''',
	    type='boolean'),
	Config('session_max', '100', r'''
	    maximum expected number of sessions (including server
	    threads)''',
	    min='1'),
	Config('statistics_log', '', r'''
	    log any statistics the database is configured to maintain,
	    to a file.  See @ref statistics for more information''',
	    type='category', subconfig=[
	    Config('path', '"WiredTigerStat.%d.%H"', r'''
	        the pathname to a file into which the log records are written,
	        may contain ISO C standard strftime conversion specifications.
	        If the value is not an absolute path name, the file is created
	        relative to the database home'''),
	    Config('sources', '', r'''
	        if non-empty, include statistics for the list of data source
	        URIs, if they are open at the time of the statistics logging.
	        The list may include URIs matching a single data source
	        ("table:mytable"), or a URI matching all data sources of a
	        particular type ("table:")''',
	        type='list'),
	    Config('timestamp', '"%b %d %H:%M:%S"', r'''
	        a timestamp prepended to each log record, may contain strftime
	        conversion specifications'''),
	    Config('wait', '0', r'''
	        seconds to wait between each write of the log records''',
	        min='1', max='100000'),
	    ]),
	Config('transaction_sync', 'fsync', r'''
	    how to sync log records when the transaction commits''',
	    choices=['dsync', 'fsync', 'none']),
	Config('use_environment_priv', 'false', r'''
	    use the \c WIREDTIGER_CONFIG and \c WIREDTIGER_HOME environment
	    variables regardless of whether or not the process is running
	    with special privileges.  See @ref home for more information''',
	    type='boolean'),
]),
}