@spec before_all() :: t()

An offset that is smaller than all offsets in the log.

Examples

iex> compare(before_all(), first())
:lt

Compare two log offsets

Examples

iex> compare(new(10, 0), new(10, 1))
:lt

iex> compare(new(9, 1), new(10, 1))
:lt

iex> compare(new(10, 1), new(10, 0))
:gt

iex> compare(new(11, 1), new(10, 1))
:gt

iex> compare(new(0, 0), before_all())
:gt

iex> compare(new(10, 0), %LogOffset{tx_offset: 10, op_offset: 0})
:eq

@spec extract_lsn(t()) :: Electric.Postgres.Lsn.t()

Returns the LSN part of the LogOffset.

Examples

iex> extract_lsn(%LogOffset{tx_offset: 10, op_offset: 0})
#Lsn<0/A>

iex> extract_lsn(%LogOffset{tx_offset: 10, op_offset: 5})
#Lsn<0/A>

iex> extract_lsn(%LogOffset{tx_offset: 11, op_offset: 5})
#Lsn<0/B>

iex> extract_lsn(LogOffset.before_all())
#Lsn<0/0>

@spec first() :: t()

The first possible offset in the log.

@spec from_string(String.t()) :: {:ok, t()} | {:error, String.t()}

Parse the given string as a LogOffset value.

Examples

iex> from_string("-1")
{:ok, before_all()}

iex> from_string("0_0")
{:ok, %LogOffset{tx_offset: 0, op_offset: 0}}

iex> from_string("11_13")
{:ok, %LogOffset{tx_offset: 11, op_offset: 13}}

iex> from_string("0_02")
{:ok, %LogOffset{tx_offset: 0, op_offset: 2}}

iex> from_string("0_inf")
{:ok, %LogOffset{tx_offset: 0, op_offset: :infinity}}

iex> from_string("1_2_3")
{:error, "has invalid format"}

iex> from_string("1_2 ")
{:error, "has invalid format"}

iex> from_string("10")
{:error, "has invalid format"}

iex> from_string("10_32.1")
{:error, "has invalid format"}

Increments the offset of the change inside the transaction.

Examples

iex> increment(new(10, 5))
%LogOffset{tx_offset: 10, op_offset: 6}

iex> compare(new(10, 5) |> increment, new(10, 5))
:gt

iex> increment(new(10, 5), 5)
%LogOffset{tx_offset: 10, op_offset: 10}

iex> compare(new(10, 1) |> increment(4), new(10, 5))
:eq

@spec last() :: t()

The last possible offset in the log.

Examples

iex> compare(first(), last())
:lt

iex> compare(new(Lsn.from_integer(10), 0), last())
:lt

@spec last_before_real_offsets() :: t()

The last possible offset for the "virtual" part of the log - i.e. snapshots.

Get a maximum of 2 log offsets

Examples

iex> LogOffset.max(new(10, 0), new(10, 1))
new(10, 1)

Get a minimum of 2 log offsets

Examples

iex> LogOffset.min(new(10, 0), new(10, 1))
new(10, 0)

Create a new LogOffset value.

Examples

iex> new(Lsn.from_integer(10), 0)
%LogOffset{tx_offset: 10, op_offset: 0}

iex> new(11, 3)
%LogOffset{tx_offset: 11, op_offset: 3}

iex> new(to_tuple(new(Lsn.from_integer(5), 1)))
%LogOffset{tx_offset: 5, op_offset: 1}

iex> new({11, 3})
%LogOffset{tx_offset: 11, op_offset: 3}

iex> new({11, 3.2})
** (FunctionClauseError) no function clause matching in Electric.Replication.LogOffset.new/2

iex> new(10, -2)
** (FunctionClauseError) no function clause matching in Electric.Replication.LogOffset.new/2

Convert the log offset to a binary representation used on disk, sized to int128

@spec to_iolist(t()) :: iolist()

Format a LogOffset value to its text representation in an iolist.

Examples

iex> to_iolist(first())
["0", ?_, "0"]

iex> to_iolist(new(Lsn.from_integer(10), 3))
["10", ?_, "3"]

iex> to_iolist(before_all())
["-1"]

@spec to_tuple(t()) :: {int64(), non_neg_integer()}

Returns a tuple with the tx_offset and the op_offset.

Examples

iex> to_tuple(first())
{0, 0}

iex> to_tuple(new(Lsn.from_integer(10), 3))
{10, 3}