- Sharding >
- Sharding Reference
Sharding Reference¶
Sharding Methods in the mongo Shell¶
| Name | Description |
|---|---|
| sh._adminCommand() | Runs a database command against the admin database, like db.runCommand(), but can confirm that it is issued against a mongos. |
| sh.getBalancerLockDetails() | Reports on the active balancer lock, if it exists. |
| sh._checkFullName() | Tests a namespace to determine if its well formed. |
| sh._checkMongos() | Tests to see if the mongo shell is connected to a mongos instance. |
| sh._lastMigration() | Reports on the last chunk migration. |
| sh.addShard() | Adds a shard to a sharded cluster. |
| sh.addShardTag() | Associates a shard with a tag, to support tag aware sharding. |
| sh.addTagRange() | Associates range of shard keys with a shard tag, to support tag aware sharding. |
| sh.removeTagRange() | Removes an association between a range shard keys and a shard tag. Use to manage tag aware sharding. |
| sh.disableBalancing() | Disable balancing on a single collection in a sharded database. Does not affect balancing of other collections in a sharded cluster. |
| sh.enableBalancing() | Activates the sharded collection balancer process if previously disabled using sh.disableBalancing(). |
| sh.enableSharding() | Enables sharding on a specific database. |
| sh.getBalancerHost() | Returns the name of a mongos that’s responsible for the balancer process. |
| sh.getBalancerState() | Returns a boolean to report if the balancer is currently enabled. |
| sh.help() | Returns help text for the sh methods. |
| sh.isBalancerRunning() | Returns a boolean to report if the balancer process is currently migrating chunks. |
| sh.moveChunk() | Migrates a chunk in a sharded cluster. |
| sh.removeShardTag() | Removes the association between a shard and a shard tag. |
| sh.setBalancerState() | Enables or disables the balancer which migrates chunks between shards. |
| sh.shardCollection() | Enables sharding for a collection. |
| sh.splitAt() | Divides an existing chunk into two chunks using a specific value of the shard key as the dividing point. |
| sh.splitFind() | Divides an existing chunk that contains a document matching a query into two approximately equal chunks. |
| sh.startBalancer() | Enables the balancer and waits for balancing to start. |
| sh.status() | Reports on the status of a sharded cluster, as db.printShardingStatus(). |
| sh.stopBalancer() | Disables the balancer and waits for any in progress balancing rounds to complete. |
| sh.waitForBalancer() | Internal. Waits for the balancer state to change. |
| sh.waitForBalancerOff() | Internal. Waits until the balancer stops running. |
| sh.waitForDLock() | Internal. Waits for a specified distributed sharded cluster lock. |
| sh.waitForPingChange() | Internal. Waits for a change in ping state from one of the mongos in the sharded cluster. |
Sharding Database Commands¶
The following database commands support sharded clusters.
| Name | Description |
|---|---|
| flushRouterConfig | Forces an update to the cluster metadata cached by a mongos. |
| addShard | Adds a shard to a sharded cluster. |
| cleanupOrphaned | Removes orphaned data with shard key values outside of the ranges of the chunks owned by a shard. |
| checkShardingIndex | Internal command that validates index on shard key. |
| enableSharding | Enables sharding on a specific database. |
| listShards | Returns a list of configured shards. |
| removeShard | Starts the process of removing a shard from a sharded cluster. |
| getShardMap | Internal command that reports on the state of a sharded cluster. |
| getShardVersion | Internal command that returns the config server version. |
| mergeChunks | Provides the ability to combine chunks on a single shard. |
| setShardVersion | Internal command to sets the config server version. |
| shardCollection | Enables the sharding functionality for a collection, allowing the collection to be sharded. |
| shardingState | Reports whether the mongod is a member of a sharded cluster. |
| unsetSharding | Internal command that affects connections between instances in a MongoDB deployment. |
| split | Creates a new chunk. |
| splitChunk | Internal command to split chunk. Instead use the methods sh.splitFind() and sh.splitAt(). |
| splitVector | Internal command that determines split points. |
| medianKey | Deprecated internal command. See splitVector. |
| moveChunk | Internal command that migrates chunks between shards. |
| movePrimary | Reassigns the primary shard when removing a shard from a sharded cluster. |
| isdbgrid | Verifies that a process is a mongos. |
Reference Documentation¶
- Config Database
- Complete documentation of the content of the local database that MongoDB uses to store sharded cluster metadata.
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