ltdts_recvlogical

ltdts_recvlogical — is forked from lt_recvlogical, so it has most all behavior that in lt_recvlogical, such as control LightDB logical decoding streams. After that, it use wal2sql plugin transform the change from LightDB to Oracle database, and future will support Redis, Kafka, LightDB-A and so on.

Synopsis

ltdts_recvlogical [option...]

Description

ltdts_recvlogical controls logical decoding replication slots and streams data from such replication slots.

Note

In HA environment, make sure you are start $LTHOME/bin/ltdts_logicalrepl_copier.sh.

It creates a replication-mode connection, so it is subject to the same constraints as lt_receivewal, plus those for logical replication (see Chapter 45).

ltdts_recvlogical has no equivalent to the logical decoding SQL interface's peek and get modes. It sends replay confirmations for data lazily as it receives it and on clean exit. To examine pending data on a slot without consuming it, use pg_logical_slot_peek_changes.

Options

At least one of the following options must be specified to select an action:

--create-slot

Create a new logical replication slot with the name specified by --slot, using the output plugin specified by --plugin, for the database specified by --dbname.

--drop-slot

Drop the replication slot with the name specified by --slot, then exit.

--start

Begin streaming changes from the logical replication slot specified by --slot, continuing until terminated by a signal. If the server side change stream ends with a server shutdown or disconnect, retry in a loop unless --no-loop is specified.

The stream format is determined by the output plugin specified when the slot was created.

The connection must be to the same database used to create the slot.

--create-slot and --start can be specified together. --drop-slot cannot be combined with another action.

The following command-line options control the location and format of the output and other replication behavior:

-E lsn
--endpos=lsn

In --start mode, automatically stop replication and exit with normal exit status 0 when receiving reaches the specified LSN. If specified when not in --start mode, an error is raised.

If there's a record with LSN exactly equal to lsn, the record will be output.

The --endpos option is not aware of transaction boundaries and may truncate output partway through a transaction. Any partially output transaction will not be consumed and will be replayed again when the slot is next read from. Individual messages are never truncated.

-f filename
--file=filename

Write received and decoded transaction data into this file. Use - for stdout.

-F interval_seconds
--fsync-interval=interval_seconds

Specifies how often ltdts_recvlogical should issue fsync() calls to ensure the output file is safely flushed to disk.

The server will occasionally request the client to perform a flush and report the flush position to the server. This setting is in addition to that, to perform flushes more frequently.

Specifying an interval of 0 disables issuing fsync() calls altogether, while still reporting progress to the server. In this case, data could be lost in the event of a crash.

-I lsn
--startpos=lsn

In --start mode, start replication from the given LSN. For details on the effect of this, see the documentation in Chapter 45 and Section 49.4. Ignored in other modes.

--if-not-exists

Do not error out when --create-slot is specified and a slot with the specified name already exists.

-n
--no-loop

When the connection to the server is lost, do not retry in a loop, just exit.

-o name[=value]
--option=name[=value]

Pass the option name to the output plugin with, if specified, the option value value. Which options exist and their effects depends on the used output plugin.

-P plugin
--plugin=plugin

When creating a slot, use the specified logical decoding output plugin. See Chapter 45. This option has no effect if the slot already exists.

-s interval_seconds
--status-interval=interval_seconds

This option has the same effect as the option of the same name in lt_receivewal. See the description there.

-S slot_name
--slot=slot_name

In --start mode, use the existing logical replication slot named slot_name. In --create-slot mode, create the slot with this name. In --drop-slot mode, delete the slot with this name.

-v
--no-verbose

Disable verbose mode.

The following command-line options control the database connection parameters.

-d dbname
--dbname=dbname

The database to connect to. See the description of the actions for what this means in detail. The dbname can be a connection string. If so, connection string parameters will override any conflicting command line options. Defaults to the user name.

-h hostname-or-ip
--host=hostname-or-ip

Specifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory for the Unix domain socket. The default is taken from the LTHOST environment variable, if set, else a Unix domain socket connection is attempted.

-p port
--port=port

Specifies the TCP port or local Unix domain socket file extension on which the server is listening for connections. Defaults to the LTPORT environment variable, if set, or a compiled-in default.

-U user
--username=user

User name to connect as. Defaults to current operating system user name.

-w
--no-password

Never issue a password prompt. If the server requires password authentication and a password is not available by other means such as a .pgpass file, the connection attempt will fail. This option can be useful in batch jobs and scripts where no user is present to enter a password.

-W
--password

Force ltdts_recvlogical to prompt for a password before connecting to a database.

This option is never essential, since ltdts_recvlogical will automatically prompt for a password if the server demands password authentication. However, ltdts_recvlogical will waste a connection attempt finding out that the server wants a password. In some cases it is worth typing -W to avoid the extra connection attempt.

-T target_type
--target=target_type

sync to where. only-debug|oracle|lightdb|redis|kafka|es|mysql. LightDB 22.2 only support only-debug(not insert oracle, just to json parse)|oracle target.

The following command-line options control the Oracle database connection parameters.

-t tnsname
--tnsname=TNSNAME

The Oracle tnsname to connect to.

-u Oracle username
--oracle-username=NAME

Specifies the username to connnect to Oracle.

-k Oracle password
--oracle-password=PASSWORD

Specifies the password to connnect to Oracle.

--ignore-duplicate

Ignore duplicate error when insert into Oracle.

--ignore-not-found

Ignore 0 effected rows when update or delete to Oracle.

-z date format
--date_format=DATE_FORMAT

nls_date_format, default is YYYY-MM-DD HH24:MI:SS.

-Z date format
--timestamp_format=TIMESTAMP_FORMAT

nls_timestamp_format, default is YYYY-MM-DD HH24:MI:SS.FF6.

The following additional options are available:

-V
--version

Print the ltdts_recvlogical version and exit.

-?
--help

Show help about ltdts_recvlogical command line arguments, and exit.

Environment

This utility, like most other LightDB utilities, uses the environment variables supported by libpq (see Section 32.14).

The environment variable LT_COLOR specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

Notes

ltdts_recvlogical will preserve group permissions on the received WAL files if group permissions are enabled on the source cluster.

See Also

lt_receivewal