# This file is a python script that describes the WiredTiger API.
class Method:
def __init__(self, config):
# Deal with duplicates: with complex configurations (like
# WT_SESSION::create), it's simpler to deal with duplicates once than
# manually as configurations are defined
self.config = []
lastname = None
for c in sorted(config):
if '.' in c.name:
raise "Bad config key '%s'" % c.name
if c.name == lastname:
continue
lastname = c.name
self.config.append(c)
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
# Comparators for sorting.
def __eq__(self, other):
return self.name == other.name
def __ne__(self, other):
return self.name != other.name
def __lt__(self, other):
return self.name < other.name
def __le__(self, other):
return self.name <= other.name
def __gt__(self, other):
return self.name > other.name
def __ge__(self, other):
return self.name >= other.name
common_runtime_config = [
Config('app_metadata', '', r'''
application-owned metadata for this object'''),
Config('assert', '', r'''
enable enhanced checking. ''',
type='category', subconfig= [
Config('commit_timestamp', 'none', r'''
This option is no longer supported. Retained for backward
compatibility. Use \c write_timestamp option instead.''',
choices=['always', 'key_consistent', 'never', 'none']),
Config('durable_timestamp', 'none', r'''
This option is no longer supported. Retained for backward
compatibility. Use \c write_timestamp option instead.''',
choices=['always', 'key_consistent', 'never', 'none']),
Config('write_timestamp', 'off', r'''
verify that commit timestamps are used per the configured
\c write_timestamp_usage option for this table''',
choices=['off', 'on']),
Config('read_timestamp', 'none', r'''
verify that timestamps should \c always or \c never be used
on reads with this table. Verification is \c none
if mixed read use is allowed''',
choices=['always', 'never', 'none'])
], undoc=True),
Config('verbose', '[]', r'''
enable messages for various events. Options are given as a
list, such as "verbose=[write_timestamp]"
''',
type='list', choices=[
'write_timestamp',
]),
Config('write_timestamp_usage', 'none', r'''
describe how timestamps are expected to be used on modifications to
the table. This option should be used in conjunction with the
corresponding \c write_timestamp configuration under the \c assert and
\c verbose options to provide logging and assertions for incorrect
timestamp usage. The choices are \c always which ensures a timestamp is
used for every operation on a table, \c key_consistent to ensure that
once timestamps are used for a key, they are always used, \c ordered is
like \c key_consistent except it also enforces that subsequent updates
to each key must use increasing timestamps, \c mixed_mode is like
\c ordered except that updates with no timestamp are allowed and have
the effect of resetting the chain of updates once the transaction ID
based snapshot is no longer relevant, \c never enforces that timestamps
are never used for a table and \c none does not enforce any expectation
on timestamp usage meaning that no log message or assertions will be
produced regardless of the corresponding \c assert and \c verbose
settings''',
choices=['always', 'key_consistent', 'mixed_mode', 'never', 'none', 'ordered']),
]
# Metadata shared by all schema objects
common_meta = common_runtime_config + [
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_custom', '', r'''
configure the tree to merge into a custom data source''',
type='category', subconfig=[
Config('prefix', '', r'''
custom data source prefix instead of \c "file"'''),
Config('start_generation', '0', r'''
merge generation at which the custom data source is used
(zero indicates no custom data source)''',
min='0', max='10'),
Config('suffix', '', r'''
custom data source suffix instead of \c ".lsm"'''),
]),
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'),
]),
]
tiered_config = common_runtime_config + [
Config('tiered', '', r'''
options only relevant for tiered data sources''',
type='category', subconfig=[
Config('chunk_size', '1GB', r'''
the maximum size of the hot chunk of tiered tree. This
limit is soft - it is possible for chunks to be temporarily
larger than this value''',
min='1M'),
Config('tiers', '', r'''
list of data sources to combine into a tiered storage structure''', type='list')
]),
]
file_runtime_config = common_runtime_config + [
Config('access_pattern_hint', 'none', r'''
It is recommended that workloads that consist primarily of
updates and/or point queries specify \c random. Workloads that
do many cursor scans through large ranges of data specify
\c sequential and other workloads specify \c none. The
option leads to an advisory call to an appropriate operating
system API where available''',
choices=['none', 'random', 'sequential']),
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('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('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('readonly', 'false', r'''
the file is read-only. All methods that may modify a file are
disabled. See @ref readonly for more information''',
type='boolean'),
]
# Per-file configuration
file_config = format_meta + file_runtime_config + [
Config('block_allocation', 'best', r'''
configure block allocation. Permitted values are \c "best" or \c "first";
the \c "best" configuration uses a best-fit algorithm,
the \c "first" configuration uses a first-available algorithm during block allocation,
the \c "log-structure" configuration allocates a new file for each checkpoint''',
choices=['best', 'first', 'log-structured',]),
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 "lz4", \c "snappy", \c "zlib" or \c "zstd" compression, these names
are also available. See @ref compression for more information'''),
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'''
This option is no longer supported. Retained for backward
compatibility. 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('ignore_in_memory_cache_size', 'false', r'''
allow update and insert operations to proceed even if the cache is
already at capacity. Only valid in conjunction with in-memory
databases. Should be used with caution - this configuration allows
WiredTiger to consume memory over the configured cache limit''',
type='boolean'),
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('memory_page_image_max', '0', r'''
the maximum in-memory page image represented by a single storage block.
Depending on compression efficiency, compression can create storage
blocks which require significant resources to re-instantiate in the
cache, penalizing the performance of future point updates. The value
limits the maximum in-memory page image a storage block will need. If
set to 0, a default of 4 times \c leaf_page_max is used''',
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 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('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', '90', 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='50', max='100'),
Config('tiered_storage', '', r'''
configure a storage source for this table''',
type='category', subconfig=[
Config('name', 'none', r'''
Permitted values are \c "none"
or custom storage source name created with
WT_CONNECTION::add_storage_source.
See @ref custom_storage_sources for more information'''),
Config('auth_token', '', r'''
authentication string identifier'''),
Config('bucket', '', r'''
The bucket indicating the location for this table'''),
Config('local_retention', '300', r'''
time in seconds to retain data on tiered storage on the local tier
for faster read access''',
min='0', max='10000'),
Config('object_target_size', '10M', r'''
the approximate size of objects before creating them on the
tiered storage tier''',
min='100K', max='10TB'),
]),
]
# File metadata, including both configurable and non-configurable (internal)
file_meta = file_config + [
Config('checkpoint', '', r'''
the file checkpoint entries'''),
Config('checkpoint_backup_info', '', r'''
the incremental backup durable information'''),
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'''),
]
tiered_meta = tiered_config
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('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_max_wait_ms', '0', r'''
the maximum number of milliseconds an application thread will wait
for space to be available in cache before giving up. Default will
wait forever''',
min=0),
Config('history_store', '', r'''
history store configuration options''',
type='category', subconfig=[
Config('file_max', '0', r'''
The maximum number of bytes that WiredTiger is allowed to use for
its history store mechanism. If the history store file exceeds
this size, a panic will be triggered. The default value means that
the history store file is unbounded and may use as much space as
the filesystem will accommodate. The minimum non-zero setting is
100MB.''', # !!! Must match WT_HS_FILE_MIN
min='0')
]),
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('debug_mode', '', r'''
control the settings of various extended debugging features''',
type='category', subconfig=[
Config('corruption_abort', 'true', r'''
if true, dump the core in the diagnostic mode on encountering the data corruption.''',
type='boolean'),
Config('checkpoint_retention', '0', r'''
adjust log archiving to retain the log records of this number
of checkpoints. Zero or one means perform normal archiving.''',
min='0', max='1024'),
Config('cursor_copy', 'false', r'''
if true, use the system allocator to make a copy of any data
returned by a cursor operation and return the copy instead.
The copy is freed on the next cursor operation. This allows
memory sanitizers to detect inappropriate references to memory
owned by cursors.''',
type='boolean'),
Config('eviction', 'false', r'''
if true, modify internal algorithms to change skew to force
history store eviction to happen more aggressively. This includes but
is not limited to not skewing newest, not favoring leaf pages,
and modifying the eviction score mechanism.''',
type='boolean'),
Config('log_retention', '0', r'''
adjust log archiving to retain at least this number of log files, ignored if set to 0.
(Warning: this option can remove log files required for recovery if no checkpoints
have yet been done and the number of log files exceeds the configured value. As
WiredTiger cannot detect the difference between a system that has not yet checkpointed
and one that will never checkpoint, it might discard log files before any checkpoint is
done.)''',
min='0', max='1024'),
Config('realloc_exact', 'false', r'''
if true, reallocation of memory will only provide the exact
amount requested. This will help with spotting memory allocation
issues more easily.''',
type='boolean'),
Config('rollback_error', '0', r'''
return a WT_ROLLBACK error from a transaction operation about
every Nth operation to simulate a collision''',
min='0', max='10M'),
Config('slow_checkpoint', 'false', r'''
if true, slow down checkpoint creation by slowing down internal
page processing.''',
type='boolean'),
Config('table_logging', 'false', r'''
if true, write transaction related information to the log for all
operations, even operations for tables with logging turned off.
This setting introduces a log format change that may break older
versions of WiredTiger. These operations are informational and
skipped in recovery.''',
type='boolean'),
]),
Config('error_prefix', '', r'''
prefix string for error messages'''),
Config('eviction', '', r'''
eviction configuration options''',
type='category', subconfig=[
Config('threads_max', '8', 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', '1', r'''
perform eviction at the beginning of checkpoints to bring the dirty
content in cache to this level. It is a percentage of the cache size if
the value is within the range of 0 to 100 or an absolute size when
greater than 100. The value is not allowed to exceed the \c cache_size.
Ignored if set to zero.''',
min=0, max='10TB'),
Config('eviction_dirty_target', '5', r'''
perform eviction in worker threads when the cache contains at least
this much dirty content. It is a percentage of the cache size if the
value is within the range of 1 to 100 or an absolute size when greater
than 100. The value is not allowed to exceed the \c cache_size.''',
min=1, max='10TB'),
Config('eviction_dirty_trigger', '20', r'''
trigger application threads to perform eviction when the cache contains
at least this much dirty content. It is a percentage of the cache size
if the value is within the range of 1 to 100 or an absolute size when
greater than 100. The value is not allowed to exceed the \c cache_size.
This setting only alters behavior if it is lower than eviction_trigger
''', min=1, max='10TB'),
Config('eviction_target', '80', r'''
perform eviction in worker threads when the cache contains at least
this much content. It is a percentage of the cache size if the value is
within the range of 10 to 100 or an absolute size when greater than 100.
The value is not allowed to exceed the \c cache_size''',
min=10, max='10TB'),
Config('eviction_trigger', '95', r'''
trigger application threads to perform eviction when the cache contains
at least this much content. It is a percentage of the cache size if the
value is within the range of 10 to 100 or an absolute size when greater
than 100. The value is not allowed to exceed the \c cache_size''',
min=10, max='10TB'),
Config('eviction_updates_target', '0', r'''
perform eviction in worker threads when the cache contains at least
this many bytes of updates. It is a percentage of the cache size if the
value is within the range of 0 to 100 or an absolute size when greater
than 100. Calculated as half of \c eviction_dirty_target by default.
The value is not allowed to exceed the \c cache_size''',
min=0, max='10TB'),
Config('eviction_updates_trigger', '0', r'''
trigger application threads to perform eviction when the cache contains
at least this many bytes of updates. It is a percentage of the cache size
if the value is within the range of 1 to 100 or an absolute size when
greater than 100\. Calculated as half of \c eviction_dirty_trigger by default.
The value is not allowed to exceed the \c cache_size. This setting only
alters behavior if it is lower than \c eviction_trigger''',
min=0, max='10TB'),
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('io_capacity', '', r'''
control how many bytes per second are written and read. Exceeding
the capacity results in throttling.''',
type='category', subconfig=[
Config('total', '0', r'''
number of bytes per second available to all subsystems in total.
When set, decisions about what subsystems are throttled, and in
what proportion, are made internally. The minimum non-zero setting
is 1MB.''',
min='0', max='1TB'),
]),
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('operation_timeout_ms', '0', r'''
when non-zero, a requested limit on the number of elapsed real time milliseconds
application threads will take to complete database operations. Time is measured from the
start of each WiredTiger API call. There is no guarantee any operation will not take
longer than this amount of time. If WiredTiger notices the limit has been exceeded, an
operation may return a WT_ROLLBACK error. Default is to have no limit''',
min=1),
Config('operation_tracking', '', r'''
enable tracking of performance-critical functions. See
@ref operation_tracking for more information''',
type='category', subconfig=[
Config('enabled', 'false', r'''
enable operation tracking subsystem''',
type='boolean'),
Config('path', '"."', r'''
the name of a directory into which operation tracking 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('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. A
shared cache can not have absolute values configured for cache
eviction settings''',
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('tiered_manager', '', r'''
tiered storage manager configuration options''',
type='category', undoc=True, subconfig=[
Config('threads_max', '8', r'''
maximum number of threads WiredTiger will start to help manage
tiered storage maintenance. Each 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 manage
tiered storage maintenance.''',
min=1, max=20),
Config('wait', '0', r'''
seconds to wait between each periodic housekeeping of
tiered storage. Setting this value above 0 configures periodic
management inside WiredTiger''',
min='0', max='100000'),
]),
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', 'cache_walk', 'fast', 'none', 'clear', 'tree_walk']),
Config('timing_stress_for_test', '', r'''
enable code that interrupts the usual timing of operations with a goal
of uncovering race conditions and unexpected blocking. This option is
intended for use with internal stress testing of WiredTiger.''',
type='list', undoc=True,
choices=[
'aggressive_sweep', 'backup_rename', 'checkpoint_slow', 'history_store_checkpoint_delay',
'history_store_search', 'history_store_sweep_race', 'prepare_checkpoint_delay', 'split_1',
'split_2', 'split_3', 'split_4', 'split_5', 'split_6', 'split_7', 'split_8']),
Config('verbose', '[]', r'''
enable messages for various events. Options are given as a
list, such as "verbose=[evictserver,read]"
''',
type='list', choices=[
'api',
'backup',
'block',
'checkpoint',
'checkpoint_cleanup',
'checkpoint_progress',
'compact',
'compact_progress',
'error_returns',
'evict',
'evict_stuck',
'evictserver',
'fileops',
'handleops',
'log',
'history_store',
'history_store_activity',
'lsm',
'lsm_manager',
'metadata',
'mutex',
'overflow',
'read',
'reconcile',
'recovery',
'recovery_progress',
'rts',
'salvage',
'shared_cache',
'split',
'temporary',
'thread_group',
'timestamp',
'transaction',
'verify',
'version',
'write']),
]
# wiredtiger_open and WT_CONNECTION.reconfigure compatibility configurations.
compatibility_configuration_common = [
Config('release', '', r'''
compatibility release version string'''),
]
connection_reconfigure_compatibility_configuration = [
Config('compatibility', '', r'''
set compatibility version of database. Changing the compatibility
version requires that there are no active operations for the duration
of the call.''',
type='category', subconfig=
compatibility_configuration_common)
]
wiredtiger_open_compatibility_configuration = [
Config('compatibility', '', r'''
set compatibility version of database. Changing the compatibility
version requires that there are no active operations for the duration
of the call.''',
type='category', subconfig=
compatibility_configuration_common + [
Config('require_max', '', r'''
required maximum compatibility version of existing data files.
Must be greater than or equal to any release version set in the
\c release setting. Has no effect if creating the database.'''),
Config('require_min', '', r'''
required minimum compatibility version of existing data files.
Must be less than or equal to any release version set in the
\c release setting. Has no effect if creating the database.'''),
]),
]
# wiredtiger_open and WT_CONNECTION.reconfigure log configurations.
log_configuration_common = [
Config('archive', 'true', r'''
automatically archive unneeded log files''',
type='boolean'),
Config('os_cache_dirty_pct', '0', r'''
maximum dirty system buffer cache usage, as a percentage of the
log's \c file_max. If non-zero, schedule writes for dirty blocks
belonging to the log in the system buffer cache after that percentage
of the log has been written into the buffer cache without an
intervening file sync.''',
min='0', max='100'),
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 "lz4", \c "snappy", \c "zlib" or \c "zstd" 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', # !!! Must match WT_LOG_FILE_MIN
max='2GB'), # !!! Must match WT_LOG_FILE_MAX
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 "%Y-%m-%dT%H:%M:%S.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)
]
tiered_storage_configuration_common = [
Config('local_retention', '300', r'''
time in seconds to retain data on tiered storage on the local tier for
faster read access''',
min='0', max='10000'),
Config('object_target_size', '10M', r'''
the approximate size of objects before creating them on the
tiered storage tier''',
min='100K', max='10TB'),
]
connection_reconfigure_tiered_storage_configuration = [
Config('tiered_storage', '', r'''
enable tiered storage. Enabling tiered storage may use one session from the
configured session_max''',
type='category', subconfig=
tiered_storage_configuration_common)
]
wiredtiger_open_tiered_storage_configuration = [
Config('tiered_storage', '', r'''
enable tiered storage. Enabling tiered storage may use one session from the
configured session_max''',
type='category', undoc=True, subconfig=
tiered_storage_configuration_common + [
Config('auth_token', '', r'''
authentication string identifier'''),
Config('bucket', '', r'''
bucket string identifier where the objects should reside'''),
Config('bucket_prefix', '', r'''
unique string prefix to identify our objects in the bucket.
Multiple instances can share the storage bucket and this
identifier is used in naming objects'''),
Config('name', 'none', r'''
Permitted values are \c "none"
or custom storage name created with
WT_CONNECTION::add_storage_source'''),
]),
]
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('cache_cursors', 'true', r'''
enable caching of cursors for reuse. Any calls to WT_CURSOR::close
for a cursor created in this session will mark the cursor
as cached and keep it available to be reused for later calls
to WT_SESSION::open_cursor. Cached cursors may be eventually
closed. This value is inherited from ::wiredtiger_open
\c cache_cursors''',
type='boolean'),
Config('ignore_cache_size', 'false', r'''
when set, operations performed by this session ignore the cache size
and are not blocked when the cache is full. Note that use of this
option for operations that create cache pressure can starve ordinary
sessions that obey the cache size.''',
type='boolean'),
Config('isolation', 'snapshot', r'''
the default isolation level for operations in this session''',
choices=['read-uncommitted', 'read-committed', 'snapshot']),
]
wiredtiger_open_common =\
connection_runtime_config +\
wiredtiger_open_compatibility_configuration +\
wiredtiger_open_log_configuration +\
wiredtiger_open_tiered_storage_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('builtin_extension_config', '', r'''
A structure where the keys are the names of builtin extensions and the
values are passed to WT_CONNECTION::load_extension as the \c config
parameter (for example,
builtin_extension_config={zlib={compression_level=3}}
)'''),
Config('cache_cursors', 'true', r'''
enable caching of cursors for reuse. This is the default value
for any sessions created, and can be overridden in configuring
\c cache_cursors in WT_CONNECTION.open_session.''',
type='boolean'),
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 a 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)
. If set to 0, disable the file
extension for the set type. For log files, the allowed range is
between 100KB and 2GB; values larger than the configured maximum log
size and the default config would extend log files in allocations of
the maximum log file size.''',
type='list', choices=['data', 'log']),
Config('file_close_sync', 'true', r'''
control whether to flush modified files to storage independent
of a global checkpoint when closing file handles to acquire exclusive
access to a table. If set to false, and logging is disabled, API calls that
require exclusive access to tables will return EBUSY if there have been
changes made to the table since the last global checkpoint. When logging
is enabled, the value for file_close_sync
has no effect, and,
modified file is always flushed to storage when closing file handles to
acquire exclusive access to the table''',
type='boolean'),
Config('hash', '', r'''
manage resources around hash bucket arrays. All values must be a power of two.
Note that setting large values can significantly increase memory usage inside
WiredTiger''',
type='category', subconfig=[
Config('buckets', 512, r'''
configure the number of hash buckets for most system hash arrays''',
min='64', max='65536'),
Config('dhandle_buckets', 512, r'''
configure the number of hash buckets for hash arrays relating to data handles''',
min='64', max='65536'),
]),
Config('hazard_max', '1000', r'''
maximum number of simultaneous hazard pointers per session
handle''',
min=15, undoc=True),
Config('mmap', 'true', r'''
Use memory mapping when accessing files in a read-only mode''',
type='boolean'),
Config('mmap_all', 'false', r'''
Use memory mapping to read and write all data files, may not be configured with direct
I/O''',
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('salvage', 'false', r'''
open connection and salvage any WiredTiger-owned database and log
files that it detects as corrupted. This API should only be used
after getting an error return of WT_TRY_SALVAGE.
Salvage rebuilds files in place, overwriting existing files.
We recommend making a backup copy of all files with the
WiredTiger prefix prior to passing this flag.''',
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('session_table_cache', 'true', r'''
Maintain a per-session cache of tables''',
type='boolean', undoc=True), # Obsolete after WT-3476
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('verify_metadata', 'false', r'''
open connection and verify any WiredTiger metadata. This API
allows verification and detection of corruption in WiredTiger metadata.''',
type='boolean'),
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 fails 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),
'tiered.meta' : Method(tiered_meta),
'WT_CURSOR.close' : Method([]),
'WT_CURSOR.reconfigure' : Method(cursor_runtime_config),
'WT_SESSION.alter' : Method(file_runtime_config + [
Config('checkpoint', '', r'''
the file checkpoint entries''', undoc=True),
Config('exclusive_refreshed', 'true', r'''
refresh the in memory state and flush the metadata change to disk,
disabling this flag is dangerous - it will only re-write the
metadata without refreshing the in-memory information or creating
a checkpoint. The update will also only be applied to table URI
entries in the metadata, not their sub-entries.''',
type='boolean', undoc=True),
]),
'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 + tiered_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'),
Config('import', '', r'''
configure import of an existing object into the currently running database''',
type='category', subconfig=[
Config('enabled', 'false', r'''
whether to import the input URI from disk''',
type='boolean'),
Config('repair', 'false', r'''
whether to reconstruct the metadata from the raw file content''',
type='boolean'),
Config('file_metadata', '', r'''
the file configuration extracted from the metadata of the export database'''),
]),
]),
'WT_SESSION.drop' : Method([
Config('checkpoint_wait', 'true', r'''
wait for concurrent checkpoints to complete before attempting the drop
operation. If \c checkpoint_wait=false, attempt the drop operation
without waiting, 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'''
if the underlying files should 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_false_positives', 'false', r'''
return all values that pass the bloom filter, without eliminating
any false positives''',
type='boolean'),
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('debug', '', r'''
configure debug specific behavior on a cursor. Generally only
used for internal testing purposes''',
type='category', subconfig=[
Config('release_evict', 'false', r'''
Configure the cursor to evict the page positioned on when the
reset API is used''',
type='boolean')
]),
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, "pretty" selects a human-readable format (making it
incompatible with the "load") 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', 'pretty', 'print']),
Config('incremental', '', r'''
configure the cursor for block incremental backup usage. These formats
are only compatible with the backup data source; see @ref backup''',
type='category', subconfig=[
Config('consolidate', 'false', r'''
causes block incremental backup information to be consolidated if adjacent
granularity blocks are modified. If false, information will be returned in
granularity sized blocks only. This must be set on the primary backup cursor and it
applies to all files for this backup''',
type='boolean'),
Config('enabled', 'false', r'''
whether to configure this backup as the starting point for a subsequent
incremental backup''',
type='boolean'),
Config('file', '', r'''
the file name when opening a duplicate incremental backup cursor.
That duplicate cursor will return the block modifications relevant
to the given file name'''),
Config('force_stop', 'false', r'''
causes all block incremental backup information to be released. This is
on an open_cursor call and the resources will be released when this
cursor is closed. No other operations should be done on this open cursor''',
type='boolean'),
Config('granularity', '16MB', r'''
this setting manages the granularity of how WiredTiger maintains modification
maps internally. The larger the granularity, the smaller amount of information
WiredTiger need to maintain''',
min='4KB', max='2GB'),
Config('src_id', '', r'''
a string that identifies a previous checkpoint backup source as the source
of this incremental backup. This identifier must have already been created
by use of the 'this_id' configuration in an earlier backup. A source id is
required to begin an incremental backup'''),
Config('this_id', '', r'''
a string that identifies the current system state as a future backup source
for an incremental backup via 'src_id'. This identifier is required when opening
an incremental backup cursor and an error will be returned if one is not provided'''),
]),
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('read_once', 'false', r'''
results that are brought into cache from disk by this cursor will be
given less priority in the cache.''',
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 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', 'cache_walk', 'fast', 'clear', 'size', 'tree_walk']),
Config('target', '', r'''
if non-empty, backup the list of objects; valid only for a
backup data source''',
type='list'),
]),
'WT_SESSION.query_timestamp' : Method([
Config('get', 'read', r'''
specify which timestamp to query: \c commit returns the most recently
set commit_timestamp. \c first_commit returns the first set
commit_timestamp. \c prepare returns the timestamp used in preparing a
transaction. \c read returns the timestamp at which the transaction is
reading at. See @ref transaction_timestamps''',
choices=['commit', 'first_commit', 'prepare', 'read']),
]),
'WT_SESSION.reset_snapshot' : 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.flush_tier' : Method([
Config('flush_timestamp', '', r'''
flush objects to all storage sources using the specified timestamp.
The supplied value must not be older than the current oldest timestamp and it must
not be newer than the stable timestamp'''),
Config('force', 'false', r'''
force sharing of all data''',
type='boolean'),
]),
'WT_SESSION.strerror' : Method([]),
'WT_SESSION.transaction_sync' : Method([
Config('timeout_ms', '1200000', # !!! Must match WT_SESSION_BG_SYNC_MSEC
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 page addresses, time windows, 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('stable_timestamp', 'false', r'''
Ensure that no data has a start timestamp after the stable timestamp,
to be run after rollback_to_stable.''',
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('ignore_prepare', 'false', r'''
whether to ignore the updates by other prepared transactions as part of
read operations of this transaction. When \c true, forces the
transaction to be read-only. Use \c force to ignore prepared updates
and permit writes (which can cause lost updates unless the application
knows something about the relationship between prepared transactions
and the updates that are ignoring them)''',
choices=['false', 'force', 'true']),
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('operation_timeout_ms', '0', r'''
when non-zero, a requested limit on the time taken to complete operations in this
transaction. Time is measured in real time milliseconds from the start of each WiredTiger
API call. There is no guarantee any operation will not take longer than this amount of time.
If WiredTiger notices the limit has been exceeded, an operation may return a WT_ROLLBACK
error. Default is to have no limit''',
min=1),
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('read_before_oldest', 'false', r'''
allows the caller to specify a read timestamp less than the oldest timestamp but newer
than or equal to the pinned timestamp. Cannot be set to true while also rounding up the read
timestamp. See @ref transaction_timestamps''', type='boolean'),
Config('read_timestamp', '', r'''
read using the specified timestamp. The supplied value must not be
older than the current oldest timestamp. See
@ref transaction_timestamps'''),
Config('roundup_timestamps', '', r'''
round up timestamps of the transaction. This setting alters the
visibility expected in a transaction. See @ref
transaction_timestamps''',
type='category', subconfig= [
Config('prepared', 'false', r'''
applicable only for prepared transactions. Indicates if the prepare
timestamp and the commit timestamp of this transaction can be
rounded up. If the prepare timestamp is less than the oldest
timestamp, the prepare timestamp will be rounded to the oldest
timestamp. If the commit timestamp is less than the prepare
timestamp, the commit timestamp will be rounded up to the prepare
timestamp''', type='boolean'),
Config('read', 'false', r'''
if the read timestamp is less than the oldest timestamp, the
read timestamp will be rounded up to the oldest timestamp''',
type='boolean'),
]),
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('commit_timestamp', '', r'''
set the commit timestamp for the current transaction. The supplied
value must not be older than the first commit timestamp set for the
current transaction. The value must also not be older than the
current oldest and stable timestamps. See
@ref transaction_timestamps'''),
Config('durable_timestamp', '', r'''
set the durable timestamp for the current transaction. The supplied
value must not be older than the commit timestamp set for the
current transaction. The value must also not be older than the
current stable timestamp. See
@ref transaction_timestamps'''),
Config('operation_timeout_ms', '0', r'''
when non-zero, a requested limit on the time taken to complete operations in this
transaction. Time is measured in real time milliseconds from the start of each WiredTiger
API call. There is no guarantee any operation will not take longer than this amount of time.
If WiredTiger notices the limit has been exceeded, an operation may return a WT_ROLLBACK
error. Default is to have no limit''',
min=1),
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.prepare_transaction' : Method([
Config('prepare_timestamp', '', r'''
set the prepare timestamp for the updates of the current transaction.
The supplied value must not be older than any active read timestamps.
See @ref transaction_timestamps'''),
]),
'WT_SESSION.timestamp_transaction' : Method([
Config('commit_timestamp', '', r'''
set the commit timestamp for the current transaction. The supplied
value must not be older than the first commit timestamp set for the
current transaction. The value must also not be older than the
current oldest and stable timestamps. See
@ref transaction_timestamps'''),
Config('durable_timestamp', '', r'''
set the durable timestamp for the current transaction. The supplied
value must not be older than the commit timestamp set for the
current transaction. The value must also not be older than the
current stable timestamp. See
@ref transaction_timestamps'''),
Config('prepare_timestamp', '', r'''
set the prepare timestamp for the updates of the current transaction.
The supplied value must not be older than any active read timestamps.
See @ref transaction_timestamps'''),
Config('read_timestamp', '', r'''
read using the specified timestamp. The supplied value must not be
older than the current oldest timestamp. This can only be set once
for a transaction. See @ref transaction_timestamps'''),
]),
'WT_SESSION.rollback_transaction' : Method([
Config('operation_timeout_ms', '0', r'''
when non-zero, a requested limit on the time taken to complete operations in this
transaction. Time is measured in real time milliseconds from the start of each WiredTiger
API call. There is no guarantee any operation will not take longer than this amount of time.
If WiredTiger notices the limit has been exceeded, an operation may return a WT_ROLLBACK
error. Default is to have no limit''',
min=1),
]),
'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 if open in a cursor. While a hot backup is in
progress, checkpoints created prior to the start of the
backup cannot be dropped''', type='list'),
Config('force', 'false', r'''
if false (the default), checkpoints may be skipped if the underlying object has not been
modified, if true, 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'),
Config('use_timestamp', 'true', r'''
if true (the default), create the checkpoint as of the last stable timestamp if timestamps
are in use, or all current updates if there is no stable timestamp set. If false, this
option generates a checkpoint with all updates including those later than the timestamp''',
type='boolean'),
]),
'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.add_storage_source' : Method([]),
'WT_CONNECTION.close' : Method([
Config('leak_memory', 'false', r'''
don't free memory during close''',
type='boolean'),
Config('use_timestamp', 'true', r'''
by default, create the close checkpoint as of the last stable timestamp
if timestamps are in use, or all current updates if there is no
stable timestamp set. If false, this option generates a checkpoint
with all updates''',
type='boolean'),
]),
'WT_CONNECTION.debug_info' : Method([
Config('cache', 'false', r'''
print cache information''', type='boolean'),
Config('cursors', 'false', r'''
print all open cursor information''', type='boolean'),
Config('handles', 'false', r'''
print open handles information''', type='boolean'),
Config('log', 'false', r'''
print log information''', type='boolean'),
Config('sessions', 'false', r'''
print open session information''', type='boolean'),
Config('txn', 'false', r'''
print global txn information''', type='boolean'),
]),
'WT_CONNECTION.reconfigure' : Method(
connection_reconfigure_compatibility_configuration +\
connection_reconfigure_log_configuration +\
connection_reconfigure_statistics_log_configuration +\
connection_reconfigure_tiered_storage_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_CONNECTION.query_timestamp' : Method([
Config('get', 'all_durable', r'''
specify which timestamp to query:
\c all_durable returns the largest timestamp such that all timestamps
up to that value have been made durable, \c last_checkpoint returns the
timestamp of the most recent stable checkpoint, \c oldest returns the
most recent \c oldest_timestamp set with WT_CONNECTION::set_timestamp,
\c oldest_reader returns the minimum of the read timestamps of all
active readers \c pinned returns the minimum of the \c oldest_timestamp
and the read timestamps of all active readers, \c recovery returns the
timestamp of the most recent stable checkpoint taken prior to a shutdown
and \c stable returns the most recent \c stable_timestamp set with
WT_CONNECTION::set_timestamp. See @ref transaction_timestamps''',
choices=['all_durable','last_checkpoint',
'oldest','oldest_reader','pinned','recovery','stable']),
]),
'WT_CONNECTION.set_timestamp' : Method([
Config('commit_timestamp', '', r'''
(deprecated) reset the maximum commit timestamp tracked by WiredTiger.
This will cause future calls to WT_CONNECTION::query_timestamp to
ignore commit timestamps greater than the specified value until the
next commit moves the tracked commit timestamp forwards. This is only
intended for use where the application is rolling back locally
committed transactions. The supplied value must not be older than the
current oldest and stable timestamps.
See @ref transaction_timestamps'''),
Config('durable_timestamp', '', r'''
reset the maximum durable timestamp tracked by WiredTiger. This will
cause future calls to WT_CONNECTION::query_timestamp to ignore durable
timestamps greater than the specified value until the next durable
timestamp moves the tracked durable timestamp forwards. This is only
intended for use where the application is rolling back locally committed
transactions. The supplied value must not be older than the current
oldest and stable timestamps. See @ref transaction_timestamps'''),
Config('force', 'false', r'''
set timestamps even if they violate normal ordering requirements.
For example allow the \c oldest_timestamp to move backwards''',
type='boolean'),
Config('oldest_timestamp', '', r'''
future commits and queries will be no earlier than the specified
timestamp. Supplied values must be monotonically increasing, any
attempt to set the value to older than the current is silently ignored.
The supplied value must not be newer than the current
stable timestamp. See @ref transaction_timestamps'''),
Config('stable_timestamp', '', r'''
checkpoints will not include commits that are newer than the specified
timestamp in tables configured with \c log=(enabled=false). Supplied
values must be monotonically increasing, any attempt to set the value to
older than the current is silently ignored. The supplied value must
not be older than the current oldest timestamp. See
@ref transaction_timestamps'''),
]),
'WT_CONNECTION.rollback_to_stable' : Method([]),
'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'''),
]),
}