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| The default number of primaries for the graph shard when the database is created.
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|initial.dbms.default_secondaries_count
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| 0
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| [0-19]
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| The default number of secondaries for the graph shard when the database is created.
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|===
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=== Creating an empty sharded property database
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You can create an empty sharded database using the `CREATE DATABASE` command.
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The command allows you to specify the number of property shards and the topology of the graph shard.
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The following examples show how to create an empty sharded database with different configurations.
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==== Example 1: Create an empty sharded database with the default topology (1 primary, no secondaries, and 1 replica per property shard)
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[source, cypher]
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----
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CYPHER 25 CREATE DATABASE `foo-sharded`
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PROPERTY SHARDS { COUNT 3 };
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----
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==== Example 2: Create an empty sharded database with a custom topology
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[source, cypher]
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----
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CYPHER 25 CREATE DATABASE `foo-sharded`
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SET GRAPH SHARD { TOPOLOGY 1 PRIMARY 0 SECONDARIES }
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SET PROPERTY SHARDS { COUNT 3 TOPOLOGY 1 REPLICAS };
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----
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==== Example 3: Create an empty sharded database with a custom high-availability topology
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[source, cypher]
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----
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CYPHER 25 CREATE DATABASE `foo-sharded`
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SET GRAPH SHARD { TOPOLOGY 3 PRIMARY 0 SECONDARIES }
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SET PROPERTY SHARDS { COUNT 3 TOPOLOGY 2 REPLICAS };
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----
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=== Creating a sharded database from a URI
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You can create a new sharded property database from an existing database with seeding from one or more URIs.
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This is useful when you want to create a new database as a copy of an existing one, or when you want to seed a new database with data from another source.
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For more information on how seed from URI works, see the xref:database-administration/standard-databases/seed-from-uri.adoc[Create a database from a URI].
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The following example shows how to create a shared database with seeding from one or several URIs.
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==== Example 1: Create a sharded database with seeding from one URI
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[source, cypher]
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----
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CYPHER 25 CREATE DATABASE `foo-sharded`
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PROPERTY SHARDS { COUNT 3 }
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OPTIONS { seedURI: “s3://bucket/folder/” };
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----
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==== Example 2: Create a sharded database with seeding from one URI with a different name
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This one is similar to example 1, but the system looks for `other-database-g000`, etc.
Sharded databases are listed as standard databases in the `type column` when you execute `SHOW DATABASES`.
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* The status is either:
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** Equal to the status shared by all shards.
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** “Mixed”, if some shards have a different status.
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The statusMessage indicates the number of shards with different statuses, e.g., online (4) and starting (1).
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* The associated graph shard is listed as `graph shard` in the `type column`.
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* The associated property shards are listed as `property shard` in the `type column`.
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* The `shardTxnLag` column displays the number of transactions the current shard is behind compared to the most up-to-date shard allocation of the sharded database.
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The lag is expressed in negative integers, whereas the column `replicationLag` shows the number of transactions the current database is behind compared to the most up-to-date allocation of that database.
Some columns are empty for the virtual sharded database (with the name passed into the create command) and can be found on the rows of the associated graph shard instead, e.g., `lastCommittedTxn` or `replicationLag`.
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These rows are only visible if the user has either `CREATE/DROP/ALTER DATABASE`, `SET DATABASE ACCESS`, or `DATABASE MANAGEMENT` privileges.
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These rows can be distinguished by the type that has the value `graph shard` and `property shard`, respectively.
= Starting and stopping sharded property databases
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:description: Starting and stopping sharded property databases
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= Starting and stopping sharded property databases
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You can start and stop a sharded database using `START DATABASE <name>` and `STOP DATABASE <name>`.
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If the name is equal to the sharded database name, the graph shard and all its property shards are started/stopped.
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If the name is equal to a shard name, only the specified shard is stopped.
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[WARNING]
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====
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Stopping a single shard makes the database inaccessible.
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Therefore, this should only be done if you need to perform some action that requires only one shard to be offline, such as the recovery of a single shard.
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Please, do not do this unless you know what you are doing.
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