# This file is a python script that describes the WiredTiger API.
class Method:
def __init__(self, config):
self.config = config
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)
# Metadata shared by all schema objects
common_meta = [
Config('app_metadata', '', r'''
application-owned metadata for this object'''),
Config('collator', 'none', r'''
configure custom collation for keys. Permitted values are \c "none"
or a custom collator name created with WT_CONNECTION::add_collator'''),
Config('columns', '', r'''
list of the column names. Comma-separated list of the form
(column[,...]). 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 = common_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', func='__wt_struct_confchk'),
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', func='__wt_struct_confchk'),
]
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_bit_count', '16', r'''
the number of bits used per item for LSM bloom filters''',
min='2', max='1000'),
Config('bloom_config', '', r'''
config string used when creating Bloom filter files, passed
to WT_SESSION::create'''),
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_count_limit', '0', r'''
the maximum number of chunks to allow in an LSM tree. This
option automatically times out old data. As new chunks are
added old chunks will be removed. Enabling this option
disables LSM background merges''',
type='int'),
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'),
]),
]
# 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', 'none', r'''
configure a compressor for file blocks. Permitted values are \c "none"
or custom compression engine name created with
WT_CONNECTION::add_compressor. If WiredTiger has builtin support for
\c "snappy", \c "lz4" or \c "zlib" compression, these names are also
available. See @ref compression for more information'''),
Config('cache_resident', 'false', r'''
do not ever evict the object's pages from cache. Not compatible with
LSM tables; see @ref tuning_cache_resident for more information''',
type='boolean'),
Config('checksum', 'uncompressed', r'''
configure block checksums; permitted values are on
(checksum all blocks), off (checksum no blocks) and
uncompresssed (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('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('encryption', '', r'''
configure an encryptor for file blocks. When a table is created,
its encryptor is not implicitly used for any related indices
or column groups''',
type='category', subconfig=[
Config('name', 'none', r'''
Permitted values are \c "none"
or custom encryption engine name created with
WT_CONNECTION::add_encryptor.
See @ref encryption for more information'''),
Config('keyid', '', r'''
An identifier that identifies a unique instance of the encryptor.
It is stored in clear text, and thus is available when
the wiredtiger database is reopened. On the first use
of a (name, keyid) combination, the WT_ENCRYPTOR::customize
function is called with the keyid as an argument'''),
]),
Config('format', 'btree', r'''
the file format''',
choices=['btree']),
Config('huffman_key', 'none', r'''
configure Huffman encoding for keys. Permitted values are
\c "none", \c "english", \c "utf8" or \c "utf16".
See @ref huffman for more information'''),
Config('huffman_value', 'none', r'''
configure Huffman encoding for values. Permitted values are
\c "none", \c "english", \c "utf8" or \c "utf16".
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'''
historic term for internal_key_max''',
min=0, undoc=True),
Config('internal_key_max', '0', r'''
the largest key stored in an internal node, in bytes. If set, keys
larger than the specified size are stored as overflow items (which
may require additional I/O to access). The default and the maximum
allowed value are both one-tenth the size of a newly split 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_key_max', '0', r'''
the largest key stored in a leaf node, in bytes. If set, keys
larger than the specified size are stored as overflow items (which
may require additional I/O to access). The default value is
one-tenth the size of a newly split leaf page''',
min='0'),
Config('leaf_page_max', '32KB', 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_value_max', '0', r'''
the largest value stored in a leaf node, in bytes. If set, values
larger than the specified size are stored as overflow items (which
may require additional I/O to access). If the size is larger than
the maximum leaf page size, the page size is temporarily ignored
when large values are written. The default is one-half the size of
a newly split leaf page''',
min='0'),
Config('leaf_item_max', '0', r'''
historic term for leaf_key_max and leaf_value_max''',
min=0, undoc=True),
Config('log', '', r'''
the transaction log configuration for this object. Only valid if
log is enabled in ::wiredtiger_open''',
type='category', subconfig=[
Config('enabled', 'true', r'''
if false, this object has checkpoint-level durability''',
type='boolean'),
]),
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 leaf_page_max, and an upper bound of
cache_size / 10. 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', 'false', 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_deepen_min_child', '0', r'''
minimum entries in a page to consider deepening the tree. Pages
will be considered for splitting and deepening the search tree
as soon as there are more than the configured number of children
''',
type='int', undoc=True),
Config('split_deepen_per_child', '0', r'''
entries allocated per child when deepening the tree''',
type='int', undoc=True),
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'''),
]
lsm_meta = file_config + lsm_config + [
Config('last', '', r'''
the last allocated chunk ID'''),
Config('chunks', '', r'''
active chunks in the LSM tree'''),
Config('old_chunks', '', r'''
obsolete chunks in the LSM tree'''),
]
table_only_config = [
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'),
]
index_only_config = [
Config('extractor', 'none', r'''
configure custom extractor for indices. Permitted values are
\c "none" or an extractor name created with
WT_CONNECTION::add_extractor'''),
Config('immutable', 'false', r'''
configure the index to be immutable - that is an index is not changed
by any update to a record in the table''', type='boolean'),
]
colgroup_meta = common_meta + source_meta
index_meta = format_meta + source_meta + index_only_config + [
Config('index_key_columns', '', r'''
number of public key columns''', type='int', undoc=True),
]
table_meta = format_meta + table_only_config
# Connection runtime config, shared by conn.reconfigure and wiredtiger_open
connection_runtime_config = [
Config('async', '', r'''
asynchronous operations configuration options''',
type='category', subconfig=[
Config('enabled', 'false', r'''
enable asynchronous operation''',
type='boolean'),
Config('ops_max', '1024', r'''
maximum number of expected simultaneous asynchronous
operations''', min='1', max='4096'),
Config('threads', '2', r'''
the number of worker threads to service asynchronous requests.
Each worker thread uses a session from the configured
session_max''',
min='1', max='20'), # !!! Must match WT_ASYNC_MAX_WORKERS
]),
Config('cache_size', '100MB', r'''
maximum heap memory to allocate for the cache. A database should
configure either \c cache_size or \c shared_cache but not both''',
min='1MB', max='10TB'),
Config('cache_overhead', '8', r'''
assume the heap allocator overhead is the specified percentage, and
adjust the cache usage by that amount (for example, if there is 10GB
of data in cache, a percentage of 10 means WiredTiger treats this as
11GB). This value is configurable because different heap allocators
have different overhead and different workloads will have different
heap allocation sizes and patterns, therefore applications may need to
adjust this value based on allocator choice and behavior in measured
workloads''',
min='0', max='30'),
Config('checkpoint', '', r'''
periodically checkpoint the database. Enabling the checkpoint server
uses a session from the configured session_max''',
type='category', subconfig=[
Config('log_size', '0', r'''
wait for this amount of log record bytes to be written to
the log between each checkpoint. If non-zero, this value will
use a minimum of the log file size. A database can configure
both log_size and wait to set an upper bound for checkpoints;
setting this value above 0 configures periodic checkpoints''',
min='0', max='2GB'),
Config('wait', '0', r'''
seconds to wait between each checkpoint; setting this value
above 0 configures periodic checkpoints''',
min='0', max='100000'),
]),
Config('error_prefix', '', r'''
prefix string for error messages'''),
Config('eviction', '', r'''
eviction configuration options''',
type='category', subconfig=[
Config('threads_max', '1', r'''
maximum number of threads WiredTiger will start to help evict
pages from cache. The number of threads started will vary
depending on the current eviction load. Each eviction worker
thread uses a session from the configured session_max''',
min=1, max=20),
Config('threads_min', '1', r'''
minimum number of threads WiredTiger will start to help evict
pages from cache. The number of threads currently running will
vary depending on the current eviction load''',
min=1, max=20),
]),
Config('eviction_checkpoint_target', '15', r'''
perform eviction at the beginning of checkpoints to bring the dirty
content in cache to this level, expressed as a percentage of the total
cache size. Ignored if set to zero or \c in_memory is \c true''',
min=0, max=99),
Config('eviction_dirty_target', '5', r'''
perform eviction in worker threads when the cache contains at least
this much dirty content, expressed as a percentage of the total cache
size. Ignored if \c in_memory is \c true''',
min=1, max=99),
Config('eviction_dirty_trigger', '20', r'''
trigger application threads to perform eviction when the cache contains
at least this much dirty content, expressed as a percentage of the
total cache size. This setting only alters behavior if it is lower than
eviction_trigger. Ignored if \c in_memory is \c true''',
min=1, max=99),
Config('eviction_target', '80', r'''
perform eviction in worker threads when the cache contains at least
this much content, expressed as a percentage of the total cache size.
Must be less than \c eviction_trigger''',
min=10, max=99),
Config('eviction_trigger', '95', r'''
trigger application threads to perform eviction when the cache contains
at least this much content, expressed as a percentage of the
total cache size''', min=10, max=99),
Config('file_manager', '', r'''
control how file handles are managed''',
type='category', subconfig=[
Config('close_handle_minimum', '250', r'''
number of handles open before the file manager will look for handles
to close''', min=0),
Config('close_idle_time', '30', r'''
amount of time in seconds a file handle needs to be idle
before attempting to close it. A setting of 0 means that idle
handles are not closed''', min=0, max=100000),
Config('close_scan_interval', '10', r'''
interval in seconds at which to check for files that are
inactive and close them''', min=1, max=100000),
]),
Config('lsm_manager', '', r'''
configure database wide options for LSM tree management. The LSM
manager is started automatically the first time an LSM tree is opened.
The LSM manager uses a session from the configured session_max''',
type='category', subconfig=[
Config('worker_thread_max', '4', r'''
Configure a set of threads to manage merging LSM trees in
the database. Each worker thread uses a session handle from
the configured session_max''',
min='3', # !!! Must match WT_LSM_MIN_WORKERS
max='20'), # !!! Must match WT_LSM_MAX_WORKERS
Config('merge', 'true', r'''
merge LSM chunks where possible''',
type='boolean')
]),
Config('lsm_merge', 'true', r'''
merge LSM chunks where possible (deprecated)''',
type='boolean', undoc=True),
Config('shared_cache', '', r'''
shared cache configuration options. A database should configure
either a cache_size or a shared_cache not both. Enabling a
shared cache uses a session from the configured session_max''',
type='category', subconfig=[
Config('chunk', '10MB', r'''
the granularity that a shared cache is redistributed''',
min='1MB', max='10TB'),
Config('name', 'none', r'''
the name of a cache that is shared between databases or
\c "none" when no shared cache is configured'''),
Config('quota', '0', r'''
maximum size of cache this database can be allocated from the
shared cache. Defaults to the entire shared cache size''',
type='int'),
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('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('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. Only available if WiredTiger
is configured with --enable-verbose. Options are given as a
list, such as "verbose=[evictserver,read]"''',
type='list', choices=[
'api',
'block',
'checkpoint',
'compact',
'evict',
'evictserver',
'fileops',
'handleops',
'log',
'lsm',
'lsm_manager',
'metadata',
'mutex',
'overflow',
'read',
'rebalance',
'reconcile',
'recovery',
'salvage',
'shared_cache',
'split',
'temporary',
'thread_group',
'transaction',
'verify',
'version',
'write']),
]
# wiredtiger_open and WT_CONNECTION.reconfigure log configurations.
log_configuration_common = [
Config('archive', 'true', r'''
automatically archive unneeded log files''',
type='boolean'),
Config('prealloc', 'true', r'''
pre-allocate log files''',
type='boolean'),
Config('zero_fill', 'false', r'''
manually write zeroes into log files''',
type='boolean')
]
connection_reconfigure_log_configuration = [
Config('log', '', r'''
enable logging. Enabling logging uses three sessions from the
configured session_max''',
type='category', subconfig=
log_configuration_common)
]
wiredtiger_open_log_configuration = [
Config('log', '', r'''
enable logging. Enabling logging uses three sessions from the
configured session_max''',
type='category', subconfig=
log_configuration_common + [
Config('enabled', 'false', r'''
enable logging subsystem''',
type='boolean'),
Config('compressor', 'none', r'''
configure a compressor for log records. Permitted values are
\c "none" or custom compression engine name created with
WT_CONNECTION::add_compressor. If WiredTiger has builtin support
for \c "snappy", \c "lz4" or \c "zlib" compression, these names
are also available. See @ref compression for more information'''),
Config('file_max', '100MB', r'''
the maximum size of log files''',
min='100KB', max='2GB'),
Config('path', '"."', r'''
the name of a directory into which log files are written. The
directory must already exist. If the value is not an absolute
path, the path is relative to the database home (see @ref
absolute_path for more information)'''),
Config('recover', 'on', r'''
run recovery or error if recovery needs to run after an
unclean shutdown''',
choices=['error','on'])
]),
]
# wiredtiger_open and WT_CONNECTION.reconfigure statistics log configurations.
statistics_log_configuration_common = [
Config('json', 'false', r'''
encode statistics in JSON format''',
type='boolean'),
Config('on_close', 'false', r'''log statistics on database close''',
type='boolean'),
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, when \c json is configured, defaults
to \c "%FT%Y.000Z"'''),
Config('wait', '0', r'''
seconds to wait between each write of the log records; setting
this value above 0 configures statistics logging''',
min='0', max='100000'),
]
connection_reconfigure_statistics_log_configuration = [
Config('statistics_log', '', r'''
log any statistics the database is configured to maintain,
to a file. See @ref statistics for more information. Enabling
the statistics log server uses a session from the configured
session_max''',
type='category', subconfig=
statistics_log_configuration_common)
]
wiredtiger_open_statistics_log_configuration = [
Config('statistics_log', '', r'''
log any statistics the database is configured to maintain,
to a file. See @ref statistics for more information. Enabling
the statistics log server uses a session from the configured
session_max''',
type='category', subconfig=
statistics_log_configuration_common + [
Config('path', '"."', r'''
the name of a directory into which statistics files are written.
The directory must already exist. If the value is not an absolute
path, the path is relative to the database home (see @ref
absolute_path for more information)''')
])
]
session_config = [
Config('isolation', 'read-committed', r'''
the default isolation level for operations in this session''',
choices=['read-uncommitted', 'read-committed', 'snapshot']),
]
wiredtiger_open_common =\
connection_runtime_config +\
wiredtiger_open_log_configuration +\
wiredtiger_open_statistics_log_configuration + [
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 when direct I/O is configured,
zero elsewhere)''',
min='-1', max='1MB'),
Config('checkpoint_sync', 'true', r'''
flush files to stable storage when closing or writing
checkpoints''',
type='boolean'),
Config('direct_io', '', r'''
Use \c O_DIRECT on POSIX systems, and \c FILE_FLAG_NO_BUFFERING on
Windows to access files. Options are given as a list, such as
"direct_io=[data]". Configuring \c direct_io requires
care, see @ref tuning_system_buffer_cache_direct_io for important
warnings. Including \c "data" will cause WiredTiger data files to use
direct I/O, including \c "log" will cause WiredTiger log files to use
direct I/O, and including \c "checkpoint" will cause WiredTiger data
files opened at a checkpoint (i.e: read only) to use direct I/O.
\c direct_io should be combined with \c write_through to get the
equivalent of \c O_DIRECT on Windows''',
type='list', choices=['checkpoint', 'data', 'log']),
Config('encryption', '', r'''
configure an encryptor for system wide metadata and logs.
If a system wide encryptor is set, it is also used for
encrypting data files and tables, unless encryption configuration
is explicitly set for them when they are created with
WT_SESSION::create''',
type='category', subconfig=[
Config('name', 'none', r'''
Permitted values are \c "none"
or custom encryption engine name created with
WT_CONNECTION::add_encryptor.
See @ref encryption for more information'''),
Config('keyid', '', r'''
An identifier that identifies a unique instance of the encryptor.
It is stored in clear text, and thus is available when
the wiredtiger database is reopened. On the first use
of a (name, keyid) combination, the WT_ENCRYPTOR::customize
function is called with the keyid as an argument'''),
Config('secretkey', '', r'''
A string that is passed to the WT_ENCRYPTOR::customize function.
It is never stored in clear text, so must be given to any
subsequent ::wiredtiger_open calls to reopen the database.
It must also be provided to any "wt" commands used with
this database'''),
]),
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,
extensions=(/path/ext.so={entry=my_entry}))''',
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,
file_extend=(data=16MB)''',
type='list', choices=['data', 'log']),
Config('hazard_max', '1000', r'''
maximum number of simultaneous hazard pointers per session
handle''',
min='15'),
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). Not yet supported in WiredTiger''',
type='boolean'),
Config('readonly', 'false', r'''
open connection in read-only mode. The database must exist. All
methods that may modify a database are disabled. See @ref readonly
for more information''',
type='boolean'),
Config('session_max', '100', r'''
maximum expected number of sessions (including server
threads)''',
min='1'),
Config('session_scratch_max', '2MB', r'''
maximum memory to cache in each session''',
type='int', undoc=True),
Config('transaction_sync', '', r'''
how to sync log records when the transaction commits''',
type='category', subconfig=[
Config('enabled', 'false', r'''
whether to sync the log on every commit by default, can be
overridden by the \c sync setting to
WT_SESSION::commit_transaction''',
type='boolean'),
Config('method', 'fsync', r'''
the method used to ensure log records are stable on disk, see
@ref tune_durability for more information''',
choices=['dsync', 'fsync', 'none']),
]),
Config('write_through', '', r'''
Use \c FILE_FLAG_WRITE_THROUGH on Windows to write to files. Ignored
on non-Windows systems. Options are given as a list, such as
"write_through=[data]". Configuring \c write_through
requires care, see @ref tuning_system_buffer_cache_direct_io for
important warnings. Including \c "data" will cause WiredTiger data
files to write through cache, including \c "log" will cause WiredTiger
log files to write through cache. \c write_through should be combined
with \c direct_io to get the equivalent of POSIX \c O_DIRECT on
Windows''',
type='list', choices=['data', 'log']),
]
wiredtiger_open = wiredtiger_open_common + [
Config('config_base', 'true', r'''
write the base configuration file if creating the database. If
\c false in the config passed directly to ::wiredtiger_open, will
ignore any existing base configuration file in addition to not creating
one. See @ref config_base for more information''',
type='boolean'),
Config('create', 'false', r'''
create the database if it does not exist''',
type='boolean'),
Config('exclusive', 'false', r'''
fail if the database already exists, generally used with the
\c create option''',
type='boolean'),
Config('in_memory', 'false', r'''
keep data in-memory only. See @ref in_memory for more information''',
type='boolean'),
Config('use_environment', 'true', r'''
use the \c WIREDTIGER_CONFIG and \c WIREDTIGER_HOME environment
variables if the process is not running with special privileges.
See @ref home for more information''',
type='boolean'),
Config('use_environment_priv', 'false', r'''
use the \c WIREDTIGER_CONFIG and \c WIREDTIGER_HOME environment
variables even if the process is running with special privileges.
See @ref home for more information''',
type='boolean'),
]
cursor_runtime_config = [
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('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'),
]
methods = {
'colgroup.meta' : Method(colgroup_meta),
'file.config' : Method(file_config),
'file.meta' : Method(file_meta),
'index.meta' : Method(index_meta),
'lsm.meta' : Method(lsm_meta),
'table.meta' : Method(table_meta),
'WT_CURSOR.close' : Method([]),
'WT_CURSOR.reconfigure' : Method(cursor_runtime_config),
'WT_SESSION.close' : Method([]),
'WT_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'),
]),
'WT_SESSION.create' : Method(file_config + lsm_config + source_meta +
index_only_config + table_only_config + [
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'),
]),
'WT_SESSION.drop' : Method([
Config('checkpoint_wait', 'true', r'''
wait for the checkpoint lock, if \c checkpoint_wait=false, perform
the drop operation without taking a lock, returning EBUSY if the
operation conflicts with a running checkpoint''',
type='boolean', undoc=True),
Config('force', 'false', r'''
return success if the object does not exist''',
type='boolean'),
Config('lock_wait', 'true', r'''
wait for locks, if \c lock_wait=false, fail if any required locks are
not available immediately''',
type='boolean', undoc=True),
Config('remove_files', 'true', r'''
should the underlying files be removed?''',
type='boolean'),
]),
'WT_SESSION.join' : Method([
Config('compare', '"eq"', r'''
modifies the set of items to be returned so that the index key
satisfies the given comparison relative to the key set in this
cursor''',
choices=['eq', 'ge', 'gt', 'le', 'lt']),
Config('count', '', r'''
set an approximate count of the elements that would be included in
the join. This is used in sizing the bloom filter, and also influences
evaluation order for cursors in the join. When the count is equal
for multiple bloom filters in a composition of joins, the bloom
filter may be shared''',
type='int'),
Config('bloom_bit_count', '16', r'''
the number of bits used per item for the bloom filter''',
min='2', max='1000'),
Config('bloom_hash_count', '8', r'''
the number of hash values per item for the bloom filter''',
min='2', max='100'),
Config('operation', '"and"', r'''
the operation applied between this and other joined cursors.
When "operation=and" is specified, all the conditions implied by
joins must be satisfied for an entry to be returned by the join cursor;
when "operation=or" is specified, only one must be satisfied.
All cursors joined to a join cursor must have matching operations''',
choices=['and', 'or']),
Config('strategy', '', r'''
when set to bloom, a bloom filter is created and populated for
this index. This has an up front cost but may reduce the number
of accesses to the main table when iterating the joined cursor.
The bloom setting requires that count be set''',
choices=['bloom', 'default']),
]),
'WT_SESSION.log_flush' : Method([
Config('sync', 'on', r'''
forcibly flush the log and wait for it to achieve the synchronization
level specified. The \c background setting initiates a background
synchronization intended to be used with a later call to
WT_SESSION::transaction_sync. The \c off setting forces any
buffered log records to be written to the file system. The
\c on setting forces log records to be written to the storage device''',
choices=['background', 'off', 'on']),
]),
'WT_SESSION.log_printf' : Method([]),
'WT_SESSION.open_cursor' : Method(cursor_runtime_config + [
Config('bulk', 'false', r'''
configure the cursor for bulk-loading, a fast, initial load path
(see @ref tune_bulk_load for more information). Bulk-load may
only be used for newly created objects and applications should
use the WT_CURSOR::insert method to insert rows. When
bulk-loading, rows 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('checkpoint_wait', 'true', r'''
wait for the checkpoint lock, if \c checkpoint_wait=false, open the
cursor without taking a lock, returning EBUSY if the operation
conflicts with a running checkpoint''',
type='boolean', undoc=True),
Config('dump', '', r'''
configure the cursor for dump format inputs and outputs: "hex"
selects a simple hexadecimal format, "json" selects a JSON format
with each record formatted as fields named by column names if
available, and "print" selects a format where only non-printing
characters are hexadecimal encoded. These formats are compatible
with the @ref util_dump and @ref util_load commands''',
choices=['hex', 'json', 'print']),
Config('next_random', 'false', r'''
configure the cursor to return a pseudo-random record from the
object when the WT_CURSOR::next method is called; valid only for
row-store cursors. See @ref cursor_random for details''',
type='boolean'),
Config('next_random_sample_size', '0', r'''
cursors configured by \c next_random to return pseudo-random
records from the object randomly select from the entire object,
by default. Setting \c next_random_sample_size to a non-zero
value sets the number of samples the application expects to take
using the \c next_random cursor. A cursor configured with both
\c next_random and \c next_random_sample_size attempts to divide
the object into \c next_random_sample_size equal-sized pieces,
and each retrieval returns a record from one of those pieces. See
@ref cursor_random for details'''),
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('readonly', 'false', r'''
only query operations are supported by this cursor. An error is
returned if a modification is attempted using the cursor. The
default is false for all cursor types except for log and metadata
cursors''',
type='boolean'),
Config('skip_sort_check', 'false', r'''
skip the check of the sort order of each bulk-loaded key''',
type='boolean', undoc=True),
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 "size" is configured, only the underlying size of the
object on disk is filled in and the object is not opened. 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', 'size']),
Config('target', '', r'''
if non-empty, backup the list of objects; valid only for a
backup data source''',
type='list'),
]),
'WT_SESSION.rebalance' : Method([]),
'WT_SESSION.rename' : Method([]),
'WT_SESSION.reset' : Method([]),
'WT_SESSION.salvage' : Method([
Config('force', 'false', r'''
force salvage even of files that do not appear to be WiredTiger
files''',
type='boolean'),
]),
'WT_SESSION.strerror' : Method([]),
'WT_SESSION.transaction_sync' : Method([
Config('timeout_ms', '1200000', r'''
maximum amount of time to wait for background sync to complete in
milliseconds. A value of zero disables the timeout and returns
immediately''',
type='int'),
]),
'WT_SESSION.truncate' : Method([]),
'WT_SESSION.upgrade' : Method([]),
'WT_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_layout', 'false', r'''
Display the layout of the files as they are verified, using the
application's message handler, intended for debugging; requires
optional support from the block manager''',
type='boolean'),
Config('dump_offsets', '', r'''
Display the contents of specific on-disk blocks,
using the application's message handler, intended for debugging''',
type='list'),
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'),
Config('strict', 'false', r'''
Treat any verification problem as an error; by default, verify will
warn, but not fail, in the case of errors that won't affect future
behavior (for example, a leaked block)''',
type='boolean')
]),
'WT_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'),
Config('snapshot', '', r'''
use a named, in-memory snapshot, see
@ref transaction_named_snapshots'''),
Config('sync', '', r'''
whether to sync log records when the transaction commits,
inherited from ::wiredtiger_open \c transaction_sync''',
type='boolean'),
]),
'WT_SESSION.commit_transaction' : Method([
Config('sync', '', r'''
override whether to sync log records when the transaction commits,
inherited from ::wiredtiger_open \c transaction_sync.
The \c background setting initiates a background
synchronization intended to be used with a later call to
WT_SESSION::transaction_sync. The \c off setting does not
wait for record to be written or synchronized. The
\c on setting forces log records to be written to the storage device''',
choices=['background', 'off', 'on']),
]),
'WT_SESSION.rollback_transaction' : Method([]),
'WT_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=" to drop all checkpoints after and
including the named checkpoint, or
\c "to=" 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 set, 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'),
]),
'WT_SESSION.snapshot' : Method([
Config('drop', '', r'''
if non-empty, specifies which snapshots to drop. Where a group
of snapshots are being dropped, the order is based on snapshot
creation order not alphanumeric name order''',
type='category', subconfig=[
Config('all', 'false', r'''
drop all named snapshots''', type='boolean'),
Config('before', '', r'''
drop all snapshots up to but not including the specified name'''),
Config('names', '', r'''
drop specific named snapshots''', type='list'),
Config('to', '', r'''
drop all snapshots up to and including the specified name'''),
]),
Config('name', '', r'''specify a name for the snapshot'''),
]),
'WT_CONNECTION.add_collator' : Method([]),
'WT_CONNECTION.add_compressor' : Method([]),
'WT_CONNECTION.add_data_source' : Method([]),
'WT_CONNECTION.add_encryptor' : Method([]),
'WT_CONNECTION.add_extractor' : Method([]),
'WT_CONNECTION.async_new_op' : Method([
Config('append', 'false', r'''
append the value as a new record, creating a new record
number key; valid only for operations with record number keys''',
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('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'),
]),
'WT_CONNECTION.close' : Method([
Config('leak_memory', 'false', r'''
don't free memory during close''',
type='boolean'),
]),
'WT_CONNECTION.reconfigure' : Method(
connection_reconfigure_log_configuration +\
connection_reconfigure_statistics_log_configuration +\
connection_runtime_config
),
'WT_CONNECTION.set_file_system' : Method([]),
'WT_CONNECTION.load_extension' : Method([
Config('config', '', r'''
configuration string passed to the entry point of the
extension as its WT_CONFIG_ARG argument'''),
Config('early_load', 'false', r'''
whether this extension should be loaded at the beginning of
::wiredtiger_open. Only applicable to extensions loaded via the
wiredtiger_open configurations string''',
type='boolean'),
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'''),
]),
'WT_CONNECTION.open_session' : Method(session_config),
'WT_SESSION.reconfigure' : Method(session_config),
# There are 4 variants of the wiredtiger_open configurations.
# wiredtiger_open:
# Configuration values allowed in the application's configuration
# argument to the wiredtiger_open call.
# wiredtiger_open_basecfg:
# Configuration values allowed in the WiredTiger.basecfg file (remove
# creation-specific configuration strings and add a version string).
# wiredtiger_open_usercfg:
# Configuration values allowed in the WiredTiger.config file (remove
# creation-specific configuration strings).
# wiredtiger_open_all:
# All of the above configuration values combined
'wiredtiger_open' : Method(wiredtiger_open),
'wiredtiger_open_basecfg' : Method(wiredtiger_open_common + [
Config('version', '(major=0,minor=0)', r'''
the file version'''),
]),
'wiredtiger_open_usercfg' : Method(wiredtiger_open_common),
'wiredtiger_open_all' : Method(wiredtiger_open + [
Config('version', '(major=0,minor=0)', r'''
the file version'''),
]),
}