Fdb.System

Namespace: FoundationDB.Client · class

Helper class for reading from the reserved System subspace

Methods

ConfigKey

static Slice ConfigKey(Slice name)

Return the corresponding key for a config attribute

• name — "foo"

Returns: "\xFF/conf/foo"

static Slice ConfigKey(string name)

Return the corresponding key for a config attribute

• name — "foo"

Returns: "\xFF/conf/foo"

EstimateCountAsync

static Task<long> EstimateCountAsync(IFdbDatabase db, KeyRange range, CancellationToken ct)

Estimates the number of keys in the specified range.

• db — Database used for the operation
• range — Range defining the keys to count
• ct — Token used to cancel the operation

Returns: Number of keys k such that range.Begin <= k > range.End

If the range contains a large of number keys, the operation may need more than one transaction to complete, meaning that the number will not be transactionally accurate.

static Task<long> EstimateCountAsync<TKeyRange>(IFdbDatabase db, in TKeyRange range, CancellationToken ct)

Estimates the number of keys in the specified range.

• db — Database used for the operation
• range — Range defining the keys to count
• ct — Token used to cancel the operation

Returns: Number of keys k such that range.Begin <= k > range.End

If the range contains a large of number keys, the operation may need more than one transaction to complete, meaning that the number will not be transactionally accurate.

static Task<long> EstimateCountAsync(IFdbDatabaseProvider db, KeyRange range, CancellationToken ct)

Estimates the number of keys in the specified range.

• db — Database used for the operation
• range — Range defining the keys to count
• ct — Token used to cancel the operation

Returns: Number of keys k such that range.Begin <= k > range.End

If the range contains a large of number keys, the operation may need more than one transaction to complete, meaning that the number will not be transactionally accurate.

static Task<long> EstimateCountAsync(IFdbDatabase db, KeyRange range, IProgress<(long, Slice)> onProgress, CancellationToken ct)

Estimates the number of keys in the specified range.

• db — Database used for the operation
• range — Range defining the keys to count
• onProgress — Optional callback called every time the count is updated. The first argument is the current count, and the second argument is the last key that was found.
• ct — Token used to cancel the operation

Returns: Number of keys k such that range.Begin <= k > range.End

If the range contains a large of number keys, the operation may need more than one transaction to complete, meaning that the number will not be transactionally accurate.

static Task<long> EstimateCountAsync<TKeyRange>(IFdbDatabase db, in TKeyRange range, IProgress<(long, Slice)> onProgress, CancellationToken ct)

Estimates the number of keys in the specified range.

• db — Database used for the operation
• range — Range defining the keys to count
• onProgress — Optional callback called every time the count is updated. The first argument is the current count, and the second argument is the last key that was found.
• ct — Token used to cancel the operation

Returns: Number of keys k such that range.Begin <= k > range.End

If the range contains a large of number keys, the operation may need more than one transaction to complete, meaning that the number will not be transactionally accurate.

static Task<long> EstimateCountAsync(IFdbDatabaseProvider db, KeyRange range, IProgress<(long, Slice)> onProgress, CancellationToken ct)

Estimates the number of keys in the specified range.

• db — Database used for the operation
• range — Range defining the keys to count
• onProgress — Optional callback called every time the count is updated. The first argument is the current count, and the second argument is the last key that was found.
• ct — Token used to cancel the operation

Returns: Number of keys k such that range.Begin <= k > range.End

If the range contains a large of number keys, the operation may need more than one transaction to complete, meaning that the number will not be transactionally accurate.

static Task<long> EstimateCountAsync(IFdbDatabase db, Slice beginInclusive, Slice endExclusive, IProgress<(long, Slice)> onProgress, CancellationToken ct)

Estimates the number of keys in the specified range.

• db — Database used for the operation
• beginInclusive — Key defining the beginning of the range
• endExclusive — Key defining the end of the range
• onProgress — Optional callback called every time the count is updated. The first argument is the current count, and the second argument is the last key that was found.
• ct — Token used to cancel the operation

Returns: Number of keys k such that beginInclusive <= k > endExclusive

If the range contains a large of number keys, the operation may need more than one transaction to complete, meaning that the number will not be transactionally accurate.

static Task<long> EstimateCountAsync(IFdbDatabaseProvider db, Slice beginInclusive, Slice endExclusive, IProgress<(long, Slice)> onProgress, CancellationToken ct)

Estimates the number of keys in the specified range.

• db — Database used for the operation
• beginInclusive — Key defining the beginning of the range
• endExclusive — Key defining the end of the range
• onProgress — Optional callback called every time the count is updated. The first argument is the current count, and the second argument is the last key that was found.
• ct — Token used to cancel the operation

Returns: Number of keys k such that beginInclusive <= k > endExclusive

If the range contains a large of number keys, the operation may need more than one transaction to complete, meaning that the number will not be transactionally accurate.

GetBoundaryKeysAsync

static Task<List<Slice>> GetBoundaryKeysAsync(IFdbReadOnlyTransaction trans, Slice beginInclusive, Slice endExclusive)

Returns a list of keys k such that beginInclusive <= k < endExclusive and k is located at the start of a contiguous range stored on a single server

• trans — Transaction to use for the operation
• beginInclusive — First key (inclusive) of the range to inspect
• endExclusive — End key (exclusive) of the range to inspect

Returns: List of keys that mark the start of a new chunk

This method is not transactional. It will return an answer no older than the Transaction object it is passed, but the returned boundaries are an estimate and may not represent the exact boundary locations at any database version.

static Task<List<Slice>> GetBoundaryKeysAsync(IFdbDatabase db, Slice beginInclusive, Slice endExclusive, CancellationToken ct)

Returns a list of keys k such that beginInclusive <= k < endExclusive and k is located at the start of a contiguous range stored on a single server

• db — Database to use for the operation
• beginInclusive — First key (inclusive) of the range to inspect
• endExclusive — End key (exclusive) of the range to inspect
• ct — Token used to cancel the operation

Returns: List of keys that mark the start of a new chunk

This method is not transactional. It will return an answer no older than the Database object it is passed, but the returned boundaries are an estimate and may not represent the exact boundary locations at any database version.

static Task<List<Slice>> GetBoundaryKeysAsync(IFdbDatabaseProvider db, Slice beginInclusive, Slice endExclusive, CancellationToken ct)

Returns a list of keys k such that beginInclusive <= k < endExclusive and k is located at the start of a contiguous range stored on a single server

• db — Database to use for the operation
• beginInclusive — First key (inclusive) of the range to inspect
• endExclusive — End key (exclusive) of the range to inspect
• ct — Token used to cancel the operation

Returns: List of keys that mark the start of a new chunk

This method is not transactional. It will return an answer no older than the Database object it is passed, but the returned boundaries are an estimate and may not represent the exact boundary locations at any database version.

GetChunksAsync

static Task<List<KeyRange>> GetChunksAsync(IFdbDatabase db, KeyRange range, CancellationToken ct)

Split a range of keys into smaller chunks where each chunk represents a contiguous range stored on a single server

• db — Database to use for the operation
• range — Range of keys to split up into smaller chunks
• ct — Token used to cancel the operation

Returns: List of one or more chunks that constitutes the range, where each chunk represents a contiguous range stored on a single server. If the list contains a single range, that means that the range is small enough to fit inside a single chunk.

This method is not transactional. It will return an answer no older than the Database object it is passed, but the returned ranges are an estimate and may not represent the exact boundary locations at any database version.

static Task<List<KeyRange>> GetChunksAsync(IFdbDatabaseProvider db, KeyRange range, CancellationToken ct)

Split a range of keys into smaller chunks where each chunk represents a contiguous range stored on a single server

• db — Database to use for the operation
• range — Range of keys to split up into smaller chunks
• ct — Token used to cancel the operation

Returns: List of one or more chunks that constitutes the range, where each chunk represents a contiguous range stored on a single server. If the list contains a single range, that means that the range is small enough to fit inside a single chunk.

This method is not transactional. It will return an answer no older than the Database object it is passed, but the returned ranges are an estimate and may not represent the exact boundary locations at any database version.

static Task<List<KeyRange>> GetChunksAsync(IFdbDatabase db, Slice beginInclusive, Slice endExclusive, CancellationToken ct)

Split a range of keys into chunks representing a contiguous range stored on a single server

• db — Database to use for the operation
• beginInclusive — First key (inclusive) of the range to inspect
• endExclusive — End key (exclusive) of the range to inspect
• ct — Token used to cancel the operation

Returns: List of one or more chunks that constitutes the range, where each chunk represents a contiguous range stored on a single server. If the list contains a single range, that means that the range is small enough to fit inside a single chunk.

This method is not transactional. It will return an answer no older than the Database object it is passed, but the returned ranges are an estimate and may not represent the exact boundary locations at any database version.

static Task<List<KeyRange>> GetChunksAsync(IFdbDatabaseProvider db, Slice beginInclusive, Slice endExclusive, CancellationToken ct)

Split a range of keys into chunks representing a contiguous range stored on a single server

• db — Database to use for the operation
• beginInclusive — First key (inclusive) of the range to inspect
• endExclusive — End key (exclusive) of the range to inspect
• ct — Token used to cancel the operation

Returns: List of one or more chunks that constitutes the range, where each chunk represents a contiguous range stored on a single server. If the list contains a single range, that means that the range is small enough to fit inside a single chunk.

This method is not transactional. It will return an answer no older than the Database object it is passed, but the returned ranges are an estimate and may not represent the exact boundary locations at any database version.

GetClientStatusAsync

static Task<FdbClientStatus> GetClientStatusAsync(IFdbDatabase db, CancellationToken ct)

Queries the current status of the client

Returns: Task that returns a FdbClientStatus instance that wraps the parsed JSON document.

Requires API version 730 or greater

static Task<FdbClientStatus> GetClientStatusAsync(IFdbDatabaseProvider db, CancellationToken ct)

Queries the current status of the client

Requires API version 730 or greater

GetConfigParameterAsync

static Task<Slice> GetConfigParameterAsync(IFdbDatabase db, Slice name, CancellationToken ct)

Returns the value of a configuration parameter (located under '\xFF/conf/')

• db — Database to use for the operation
• name — Name of the configuration key (ex: "storage_engine")
• ct — Token used to cancel the operation

Returns: Value of '\xFF/conf/storage_engine'

static Task<Slice> GetConfigParameterAsync(IFdbDatabaseProvider db, Slice name, CancellationToken ct)

Returns the value of a configuration parameter (located under '\xFF/conf/')

• db — Database to use for the operation
• name — Name of the configuration key (ex: "storage_engine")
• ct — Token used to cancel the operation

Returns: Value of '\xFF/conf/storage_engine'

static Task<Slice> GetConfigParameterAsync(IFdbDatabase db, string name, CancellationToken ct)

Returns the value of a configuration parameter (located under '\xFF/conf/')

• db — Database to use for the operation
• name — Name of the configuration key (ex: "storage_engine")
• ct — Token used to cancel the operation

Returns: Value of '\xFF/conf/storage_engine'

static Task<Slice> GetConfigParameterAsync(IFdbDatabaseProvider db, string name, CancellationToken ct)

Returns the value of a configuration parameter (located under '\xFF/conf/')

• db — Database to use for the operation
• name — Name of the configuration key (ex: "storage_engine")
• ct — Token used to cancel the operation

Returns: Value of '\xFF/conf/storage_engine'

GetCoordinatorsAsync

static Task<FdbClusterConnectionString> GetCoordinatorsAsync(IFdbReadOnlyTransaction tr)

Returns an object describing the list of the current coordinators for the cluster

• tr — Transaction to use for the operation

Caution: This operation will set the ReadSystemKeys and PrioritySystemImmediate options on the transaction. You should avoid mixing this method and other read-heavy operations in the same transaction.

Since the list of coordinators may change at any time, the results may already be obsolete once this method completes!

static Task<FdbClusterConnectionString> GetCoordinatorsAsync(IFdbDatabase db, CancellationToken ct)

Returns an object describing the list of the current coordinators for the cluster

• db — Database to use for the operation
• ct — Token used to cancel the operation

Since the list of coordinators may change at any time, the results may already be obsolete once this method completes!

static Task<FdbClusterConnectionString> GetCoordinatorsAsync(IFdbDatabaseProvider db, CancellationToken ct)

Returns an object describing the list of the current coordinators for the cluster

• db — Database Provider to use for the operation
• ct — Token used to cancel the operation

Since the list of coordinators may change at any time, the results may already be obsolete once this method completes!

GetSpecialKeyAsync

static Task<Slice> GetSpecialKeyAsync(IFdbDatabase db, Slice name, CancellationToken ct)

Returns the value of a special key (located under the \xFF\xFF prefix)

• db — Database to use for the operation
• name — Name of the special key (ex: `/management/tenant_mode`)
• ct — Token used to cancel the operation

Returns: Value of \xFF\xFF/management/tenant_mode

static Task<Slice> GetSpecialKeyAsync(IFdbDatabaseProvider db, Slice name, CancellationToken ct)

Returns the value of a special key (located under the \xFF\xFF prefix)

• db — Database to use for the operation
• name — Name of the special key (ex: `/management/tenant_mode`)
• ct — Token used to cancel the operation

Returns: Value of \xFF\xFF/management/tenant_mode

static Task<Slice> GetSpecialKeyAsync(IFdbDatabase db, string name, CancellationToken ct)

Returns the value of a special key (located under the \xFF\xFF prefix)

• db — Database to use for the operation
• name — Name of the special key (ex: "/management/tenant_mode")
• ct — Token used to cancel the operation

Returns: Value of \xFF\xFF/management/tenant_mode

static Task<Slice> GetSpecialKeyAsync(IFdbDatabaseProvider db, string name, CancellationToken ct)

Returns the value of a special key (located under the \xFF\xFF prefix)

• db — Database to use for the operation
• name — Name of the special key (ex: `/management/tenant_mode`)
• ct — Token used to cancel the operation

Returns: Value of \xFF\xFF/management/tenant_mode

GetStatusAsync

static Task<FdbSystemStatus> GetStatusAsync(IFdbReadOnlyTransaction trans)

Query the current status of the cluster

Returns: Task that returns a FdbSystemStatus instance that wraps the parsed JSON document.

This method will read the `\xFF\xFF/status/json` special key, and parse the result JSON bytes.

static Task<FdbSystemStatus> GetStatusAsync(IFdbDatabase db, CancellationToken ct)

Queries the current status of the cluster

Returns: Task that returns a FdbSystemStatus instance that wraps the parsed JSON document.

This method will read the `\xFF\xFF/status/json` special key, and parse the result JSON bytes.

static Task<FdbSystemStatus> GetStatusAsync(IFdbDatabaseProvider db, CancellationToken ct)

Queries the current status of the cluster

Returns: Task that returns a FdbSystemStatus instance that wraps the parsed JSON document.

This method will read the `\xFF\xFF/status/json` special key, and parse the result JSON bytes.

GetStorageEngineModeAsync

static Task<string> GetStorageEngineModeAsync(IFdbDatabase db, CancellationToken ct)

Returns the current storage engine mode of the cluster

• db — Database to use for the operation
• ct — Token used to cancel the operation

Returns: Returns either "memory" or "ssd"

Will return a string starting with "unknown" if the storage engine mode is not recognized

static Task<string> GetStorageEngineModeAsync(IFdbDatabaseProvider db, CancellationToken ct)

Returns the current storage engine mode of the cluster

• db — Database to use for the operation
• ct — Token used to cancel the operation

Returns: Returns either "memory" or "ssd"

Will return a string starting with "unknown" if the storage engine mode is not recognized

GlobalsKey

static Slice GlobalsKey(string name)

Return the corresponding key for a global attribute

• name — "foo"

Returns: "\xFF/globals/foo"

SpecialKey

static Slice SpecialKey(Slice name)

Returns the corresponding key for a special key attribute

• name — Name of the special key, for example: `/foo/bar`

Returns: Name prefixed by \xFF\xFF, for example: `\xFF\xFF/foo/bar`

SpecialKey(Slice.FromString("/foo/bar")) => \xFF\xFF/foo/bar

static Slice SpecialKey(string name)

Returns the corresponding key for a special key attribute

• name — Name of the special key, for example: "/foo/bar"

Returns: Name prefixed by \xFF\xFF, for example: "\xFF\xFF/foo/bar"

SpecialKey("/foo/bar") => \xFF\xFF/foo/bar

TryParseAddress

static bool TryParseAddress(ReadOnlySpan<char> address, out IPAddress host, out int port, out bool tls)

WorkersKey

static Slice WorkersKey(string id, string name)

Return the corresponding key for a global attribute

• id — "ABC123"
• name — "foo"

Returns: "\xFF/workers/ABC123/foo"

Fields

BackupDataFormat

static readonly Slice BackupDataFormat

"\xFF/backupDataFormat"

ConfigPrefix

static readonly Slice ConfigPrefix

\xFF/conf/...

Coordinators

static readonly Slice Coordinators

\xFF/coordinators

GlobalsPrefix

static readonly Slice GlobalsPrefix

\xFF/globals/...

InitId

static readonly Slice InitId

`\xFF/init_id`

KeyServers

static readonly Slice KeyServers

`\xFF/keyServer/(key_boundary)` => (..., node_id, ...)

MaxValue

static readonly Slice MaxValue

"\xFF\xFF"

MetadataVersionKey

static readonly Slice MetadataVersionKey

"\xFF/metadataVersion"

MinValue

static readonly Slice MinValue

"\xFF\x00"

ServerKeys

static readonly Slice ServerKeys

`\xFF/serverKeys/(node_id)/(key_boundary)` => ('' | '1')

ServerList

static readonly Slice ServerList

`\xFF/serverList/(node_id)` => (..., node_id, machine_id, datacenter_id, ...)

SpecialKeyPrefix

static readonly Slice SpecialKeyPrefix

"\xFF\xFF"

StatusJson

static readonly Slice StatusJson

`\xFF\xFF/status/json` =>

TransactionConflictingKeysPrefix

static readonly Slice TransactionConflictingKeysPrefix

`\xFF\xFF/transaction/conflicting_keys/`... => ('0' | '1')

WorkersPrefix

static readonly Slice WorkersPrefix

`\xFF/workers/(ip:port)/...` => datacenter + machine + mclass