Specifies the name of the database to be dumped. If this is not specified, the environment variable LTDATABASE is used. If that is not set, the user name specified for the connection is used.

Dump only the data, not the schema (data definitions). Table data, large objects, and sequence values are dumped.

This option is similar to, but for historical reasons not identical to, specifying --section=data.

Include large objects in the dump. This is the default behavior except when --schema, --table, or --schema-only is specified. The -b switch is therefore only useful to add large objects to dumps where a specific schema or table has been requested. Note that blobs are considered data and therefore will be included when --data-only is used, but not when --schema-only is.

Exclude large objects in the dump.

When both -b and -B are given, the behavior is to output large objects, when data is being dumped, see the -b documentation.

Output commands to clean (drop) database objects prior to outputting the commands for creating them. (Unless --if-exists is also specified, restore might generate some harmless error messages, if any objects were not present in the destination database.)

This option is ignored when emitting an archive (non-text) output file. For the archive formats, you can specify the option when you call lt_restore.

Output commands to directly drop schema(use cascade mode) prior to outputting the commands for creating them, more faster then normal mode. (Unless --if-exists is also specified, restore might generate some harmless error messages, if any objects were not present in the destination database.)

This option is ignored when emitting an archive (non-text) output file. For the archive formats, you can specify the option when you call lt_restore.

Begin the output with a command to create the database itself and reconnect to the created database. (With a script of this form, it doesn't matter which database in the destination installation you connect to before running the script.) If --clean is also specified, the script drops and recreates the target database before reconnecting to it.

With --create, the output also includes the database's comment if any, and any configuration variable settings that are specific to this database, that is, any ALTER DATABASE ... SET ... and ALTER ROLE ... IN DATABASE ... SET ... commands that mention this database. Access privileges for the database itself are also dumped, unless --no-acl is specified.

This option is ignored when emitting an archive (non-text) output file. For the archive formats, you can specify the option when you call lt_restore.

Lightdb 23.3 introduced a new database level GUC parameter lightdb_ascii_zero_store_value, the value is stored in table lt_database_ext, If we run lt_dump with -C (or run lt_dumpall), this option would be included in create database statement.

For more information about GUC lightdb_ascii_zero_store_value, See lightdb_ascii_zero_store_value

Create the dump in the specified character set encoding. By default, the dump is created in the database encoding. (Another way to get the same result is to set the LTCLIENTENCODING environment variable to the desired dump encoding.)

Send output to the specified file. This parameter can be omitted for file based output formats, in which case the standard output is used. It must be given for the directory output format however, where it specifies the target directory instead of a file. In this case the directory is created by lt_dump and must not exist before.

Selects the format of the output. format can be one of the following:

Run the dump in parallel by dumping njobs tables simultaneously. This option may reduce the time needed to perform the dump but it also increases the load on the database server. You can only use this option with the directory output format because this is the only output format where multiple processes can write their data at the same time.

lt_dump will open njobs + 1 connections to the database, so make sure your max_connections setting is high enough to accommodate all connections.

Requesting exclusive locks on database objects while running a parallel dump could cause the dump to fail. The reason is that the lt_dump master process requests shared locks on the objects that the worker processes are going to dump later in order to make sure that nobody deletes them and makes them go away while the dump is running. If another client then requests an exclusive lock on a table, that lock will not be granted but will be queued waiting for the shared lock of the master process to be released. Consequently any other access to the table will not be granted either and will queue after the exclusive lock request. This includes the worker process trying to dump the table. Without any precautions this would be a classic deadlock situation. To detect this conflict, the lt_dump worker process requests another shared lock using the NOWAIT option. If the worker process is not granted this shared lock, somebody else must have requested an exclusive lock in the meantime and there is no way to continue with the dump, so lt_dump has no choice but to abort the dump.

For a consistent backup, the database server needs to support synchronized snapshots, a feature that was introduced in LightDB 9.2 for primary servers and 10 for standbys. With this feature, database clients can ensure they see the same data set even though they use different connections. lt_dump -j uses multiple database connections; it connects to the database once with the master process and once again for each worker job. Without the synchronized snapshot feature, the different worker jobs wouldn't be guaranteed to see the same data in each connection, which could lead to an inconsistent backup.

If you want to run a parallel dump of a pre-9.2 server, you need to make sure that the database content doesn't change from between the time the master connects to the database until the last worker job has connected to the database. The easiest way to do this is to halt any data modifying processes (DDL and DML) accessing the database before starting the backup. You also need to specify the --no-synchronized-snapshots parameter when running lt_dump -j against a pre-9.2 LightDB server.

Dump only schemas matching pattern; this selects both the schema itself, and all its contained objects. When this option is not specified, all non-system schemas in the target database will be dumped. Multiple schemas can be selected by writing multiple -n switches. The pattern parameter is interpreted as a pattern according to the same rules used by ltsql's \d commands (see Patterns below), so multiple schemas can also be selected by writing wildcard characters in the pattern. When using wildcards, be careful to quote the pattern if needed to prevent the shell from expanding the wildcards; see Examples below.

Do not dump any schemas matching pattern. The pattern is interpreted according to the same rules as for -n. -N can be given more than once to exclude schemas matching any of several patterns.

When both -n and -N are given, the behavior is to dump just the schemas that match at least one -n switch but no -N switches. If -N appears without -n, then schemas matching -N are excluded from what is otherwise a normal dump.

Do not output commands to set ownership of objects to match the original database. By default, lt_dump issues ALTER OWNER or SET SESSION AUTHORIZATION statements to set ownership of created database objects. These statements will fail when the script is run unless it is started by a superuser (or the same user that owns all of the objects in the script). To make a script that can be restored by any user, but will give that user ownership of all the objects, specify -O.

This option is ignored when emitting an archive (non-text) output file. For the archive formats, you can specify the option when you call lt_restore.

This option is obsolete but still accepted for backwards compatibility.

Dump only the object definitions (schema), not data.

This option is the inverse of --data-only. It is similar to, but for historical reasons not identical to, specifying --section=pre-data --section=post-data.

(Do not confuse this with the --schema option, which uses the word “schema” in a different meaning.)

To exclude table data for only a subset of tables in the database, see --exclude-table-data.

Specify the superuser user name to use when disabling triggers. This is relevant only if --disable-triggers is used. (Usually, it's better to leave this out, and instead start the resulting script as superuser.)

Dump only tables with names matching pattern. Multiple tables can be selected by writing multiple -t switches. The pattern parameter is interpreted as a pattern according to the same rules used by ltsql's \d commands (see Patterns below), so multiple tables can also be selected by writing wildcard characters in the pattern. When using wildcards, be careful to quote the pattern if needed to prevent the shell from expanding the wildcards; see Examples below.

As well as tables, this option can be used to dump the definition of matching views, materialized views, foreign tables, and sequences. It will not dump the contents of views or materialized views, and the contents of foreign tables will only be dumped if the corresponding foreign server is specified with --include-foreign-data.

The -n and -N switches have no effect when -t is used, because tables selected by -t will be dumped regardless of those switches, and non-table objects will not be dumped.

Do not dump any tables matching pattern. The pattern is interpreted according to the same rules as for -t. -T can be given more than once to exclude tables matching any of several patterns.

When both -t and -T are given, the behavior is to dump just the tables that match at least one -t switch but no -T switches. If -T appears without -t, then tables matching -T are excluded from what is otherwise a normal dump.

Specifies verbose mode. This will cause lt_dump to output detailed object comments and start/stop times to the dump file, and progress messages to standard error.

Print the lt_dump version and exit.

Prevent dumping of access privileges (grant/revoke commands).

Specify the compression level to use. Zero means no compression. For the custom and directory archive formats, this specifies compression of individual table-data segments, and the default is to compress at a moderate level. For plain text output, setting a nonzero compression level causes the entire output file to be compressed, as though it had been fed through gzip; but the default is not to compress. The tar archive format currently does not support compression at all.

This option is for use by in-place upgrade utilities. Its use for other purposes is not recommended or supported. The behavior of the option may change in future releases without notice.

Dump data as INSERT commands with explicit column names (INSERT INTO table (column, ...) VALUES ...). This will make restoration very slow; it is mainly useful for making dumps that can be loaded into non-LightDB databases. Any error during restoring will cause only rows that are part of the problematic INSERT to be lost, rather than the entire table contents.

This option disables the use of dollar quoting for function bodies, and forces them to be quoted using SQL standard string syntax.

This option is relevant only when creating a data-only dump. It instructs lt_dump to include commands to temporarily disable triggers on the target tables while the data is restored. Use this if you have referential integrity checks or other triggers on the tables that you do not want to invoke during data restore.

Presently, the commands emitted for --disable-triggers must be done as superuser. So, you should also specify a superuser name with -S, or preferably be careful to start the resulting script as a superuser.

This option is ignored when emitting an archive (non-text) output file. For the archive formats, you can specify the option when you call lt_restore.

This option is relevant only when dumping the contents of a table which has row security. By default, lt_dump will set row_security to off, to ensure that all data is dumped from the table. If the user does not have sufficient privileges to bypass row security, then an error is thrown. This parameter instructs lt_dump to set row_security to on instead, allowing the user to dump the parts of the contents of the table that they have access to.

Note that if you use this option currently, you probably also want the dump be in INSERT format, as the COPY FROM during restore does not support row security.

Do not dump data for any tables matching pattern. The pattern is interpreted according to the same rules as for -t. --exclude-table-data can be given more than once to exclude tables matching any of several patterns. This option is useful when you need the definition of a particular table even though you do not need the data in it.

To exclude data for all tables in the database, see --schema-only.

Use the specified value of extra_float_digits when dumping floating-point data, instead of the maximum available precision. Routine dumps made for backup purposes should not use this option.

Use conditional commands (i.e., add an IF EXISTS clause) when cleaning database objects. This option is not valid unless --clean is also specified.

Dump the data for any foreign table with a foreign server matching foreignserver pattern. Multiple foreign servers can be selected by writing multiple --include-foreign-data switches. Also, the foreignserver parameter is interpreted as a pattern according to the same rules used by ltsql's \d commands (see Patterns below), so multiple foreign servers can also be selected by writing wildcard characters in the pattern. When using wildcards, be careful to quote the pattern if needed to prevent the shell from expanding the wildcards; see Examples below. The only exception is that an empty pattern is disallowed.

Specify the target lightdb version.

Exclude all built-in objects created by LightDB in the dump.

Dump only the data of built-in tables which specified in 'pg_extension_config_dump' (in the extension's SQL scripts).

This tables will be truncate firstly when data is being restored.

Force escaping single quotes in the table name. This option is necessary when a table has single quotes in its name. With this option, a single ' will be escaped as ''.

Do not automatic collect statistics when dump index. (see CREATE INDEX for more details).

Dump data as INSERT commands (rather than COPY). This will make restoration very slow; it is mainly useful for making dumps that can be loaded into non-LightDB databases. Any error during restoring will cause only rows that are part of the problematic INSERT to be lost, rather than the entire table contents. Note that the restore might fail altogether if you have rearranged column order. The --column-inserts option is safe against column order changes, though even slower.

When dumping data for a table partition, make the COPY or INSERT statements target the root of the partitioning hierarchy that contains it, rather than the partition itself. This causes the appropriate partition to be re-determined for each row when the data is loaded. This may be useful when restoring data on a server where rows do not always fall into the same partitions as they did on the original server. That could happen, for example, if the partitioning column is of type text and the two systems have different definitions of the collation used to sort the partitioning column.

It is best not to use parallelism when restoring from an archive made with this option, because lt_restore will not know exactly which partition(s) a given archive data item will load data into. This could result in inefficiency due to lock conflicts between parallel jobs, or perhaps even restore failures due to foreign key constraints being set up before all the relevant data is loaded.

Do not wait forever to acquire shared table locks at the beginning of the dump. Instead fail if unable to lock a table within the specified timeout. The timeout may be specified in any of the formats accepted by SET statement_timeout. (Allowed formats vary depending on the server version you are dumping from, but an integer number of milliseconds is accepted by all versions.)

Do not dump comments.

Do not dump publications.

Do not dump security labels.

Do not dump subscriptions.

By default, lt_dump will wait for all files to be written safely to disk. This option causes lt_dump to return without waiting, which is faster, but means that a subsequent operating system crash can leave the dump corrupt. Generally, this option is useful for testing but should not be used when dumping data from production installation.

This option allows running lt_dump -j against a pre-9.2 server, see the documentation of the -j parameter for more details.

Do not output commands to select tablespaces. With this option, all objects will be created in whichever tablespace is the default during restore.

This option is ignored when emitting an archive (non-text) output file. For the archive formats, you can specify the option when you call lt_restore.

Do not dump the contents of unlogged tables. This option has no effect on whether or not the table definitions (schema) are dumped; it only suppresses dumping the table data. Data in unlogged tables is always excluded when dumping from a standby server.

Add ON CONFLICT DO NOTHING to INSERT commands. This option is not valid unless --inserts, --column-inserts or --rows-per-insert is also specified.

Force quoting of all identifiers. This option is recommended when dumping a database from a server whose LightDB major version is different from lt_dump's, or when the output is intended to be loaded into a server of a different major version. By default, lt_dump quotes only identifiers that are reserved words in its own major version. This sometimes results in compatibility issues when dealing with servers of other versions that may have slightly different sets of reserved words. Using --quote-all-identifiers prevents such issues, at the price of a harder-to-read dump script.

Dump data as INSERT commands (rather than COPY). Controls the maximum number of rows per INSERT command. The value specified must be a number greater than zero. Any error during restoring will cause only rows that are part of the problematic INSERT to be lost, rather than the entire table contents.

Only dump the named section. The section name can be pre-data, data, or post-data. This option can be specified more than once to select multiple sections. The default is to dump all sections.

The data section contains actual table data, large-object contents, and sequence values. Post-data items include definitions of indexes, triggers, rules, and constraints other than validated check constraints. Pre-data items include all other data definition items.

Use a serializable transaction for the dump, to ensure that the snapshot used is consistent with later database states; but do this by waiting for a point in the transaction stream at which no anomalies can be present, so that there isn't a risk of the dump failing or causing other transactions to roll back with a serialization_failure. See Chapter 13 for more information about transaction isolation and concurrency control.

This option is not beneficial for a dump which is intended only for disaster recovery. It could be useful for a dump used to load a copy of the database for reporting or other read-only load sharing while the original database continues to be updated. Without it the dump may reflect a state which is not consistent with any serial execution of the transactions eventually committed. For example, if batch processing techniques are used, a batch may show as closed in the dump without all of the items which are in the batch appearing.

This option will make no difference if there are no read-write transactions active when lt_dump is started. If read-write transactions are active, the start of the dump may be delayed for an indeterminate length of time. Once running, performance with or without the switch is the same.

Use the specified synchronized snapshot when making a dump of the database (see Table 9.89 for more details).

This option is useful when needing to synchronize the dump with a logical replication slot (see Chapter 44) or with a concurrent session.

In the case of a parallel dump, the snapshot name defined by this option is used rather than taking a new snapshot.

Require that each schema (-n/--schema) and table (-t/--table) qualifier match at least one schema/table in the database to be dumped. Note that if none of the schema/table qualifiers find matches, lt_dump will generate an error even without --strict-names.

This option has no effect on -N/--exclude-schema, -T/--exclude-table, or --exclude-table-data. An exclude pattern failing to match any objects is not considered an error.

Output SQL-standard SET SESSION AUTHORIZATION commands instead of ALTER OWNER commands to determine object ownership. This makes the dump more standards-compatible, but depending on the history of the objects in the dump, might not restore properly. Also, a dump using SET SESSION AUTHORIZATION will certainly require superuser privileges to restore correctly, whereas ALTER OWNER requires lesser privileges.

Show help about lt_dump command line arguments, and exit.

Specifies the name of the database to connect to. This is equivalent to specifying dbname as the first non-option argument on the command line. The dbname can be a connection string. If so, connection string parameters will override any conflicting command line options.

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.

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.

User name to connect as.

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.

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

This option is never essential, since lt_dump will automatically prompt for a password if the server demands password authentication. However, lt_dump 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.

Specifies a role name to be used to create the dump. This option causes lt_dump to issue a SET ROLE rolename command after connecting to the database. It is useful when the authenticated user (specified by -U) lacks privileges needed by lt_dump, but can switch to a role with the required rights. Some installations have a policy against logging in directly as a superuser, and use of this option allows dumps to be made without violating the policy.

Default connection parameters.

Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.