Abstract: The subject technology determines a derived encryption key using a cryptographic hash function applied to a hybrid tenant master encryption key and a local random generated identifier. The subject technology encrypts a record value and a key value associated with a transaction using the derived encryption key. The subject technology determines a non-leaf node using a tenant prefix of a tenant. The subject technology inserts the encrypted record value at a leaf node below a non-leaf node of a tree structure associated with the tenant. The subject technology receives a second transaction for performing a read operation on a distributed database. The subject technology retrieves a set of encryption keys based at least in part on an account and the tenant. The subject technology decrypts, using the set of encryption keys, data from the distributed database. The subject technology provides the decrypted data as a result of the second transaction.

Abstract: The subject technology selects a candidate compute service manager from a set of instances of compute service managers to issue a query restart by selecting an execution node, the execution node being included in a particular virtual warehouse associated with the candidate compute service manager, the selecting facilitating improving utilization of cluster resources and improving query execution on the selected candidate compute service manager. The subject technology receives a notification indicating that a particular compute service manager has been quiesced. The subject technology determines a set of jobs that are not yet scheduled for execution and eligible for query retry. The subject technology determines a second set of jobs from the set of jobs to send at least another compute service manager for execution. The subject technology sends the second set of jobs to at least another compute service manager for execution.

Abstract: The subject technology receives a transaction for performing an operation on a distributed database, the transaction associated with an account. The subject technology identifies a tenant corresponding to the account associated with the transaction. The subject technology retrieves a set of encryption keys based at least in part on the account and the tenant. The subject technology determines a derived encryption key using a cryptographic hash function applied to a hybrid tenant master encryption key and a local random generated identifier. The subject technology encrypts a record value and a key value associated with transaction using the derived encryption key. The subject technology determines a tree structure associated with the tenant. The subject technology determines a non-leaf node using a tenant prefix of the tenant. The subject technology inserts the encrypted record value, and the encrypted key value at a leaf node below the non-leaf node of the tree structure.

Abstract: The subject technology retrieves information related to a set of instances of compute service managers, each instance of a particular compute service manager being associated with a set of virtual warehouses. The subject technology filters the information to determine a set of candidates from the set of instances of compute service managers. The subject technology sorts the set of candidates based at least in part on each workload of each of the set of candidates. The subject technology selects a candidate compute service manager from the set of instances of compute service managers to issue a query restart by randomly selecting an execution node, the execution node being included in a particular virtual warehouse associated with the candidate compute service manager, the selecting facilitating improving utilization of cluster resources and improving query execution on the selected candidate compute service manager.

Abstract: The subject technology retrieves information related to a set of instances of compute service managers, each instance of a particular compute service manager being associated with a set of virtual warehouses. The subject technology filters the information to determine a set of candidates from the set of instances of compute service managers. The subject technology sorts the set of candidates based at least in part on each workload of each of the set of candidates. The subject technology selects a candidate compute service manager from the set of instances of compute service managers to issue a query restart by randomly selecting an execution node, the execution node being included in a particular virtual warehouse associated with the candidate compute service manager, the selecting facilitating improving utilization of cluster resources and improving query execution on the selected candidate compute service manager.

Abstract: The subject technology requests information regarding an instance identifier of a compute service manager instance to a particular job. The subject technology retrieves information related to a set of instances of compute service managers in a set of virtual warehouses. The subject technology filters the information to determine a set of candidates from the set of instances of compute service managers. The subject technology sorts the set of candidates based at least in part on a workload. The subject technology selects a candidate compute service manager to issue a query restart by randomly selecting an execution node.

Abstract: Techniques are described that allow each host in a multi-host system to throttle its bandwidth between multiple data nodes without the need to coordinate with the other hosts. Specifically, techniques are described in which a limit is applied to the amount of sent-but-not-acknowledged data a given host may have. If the host has reached the limit, the host must wait for acknowledgements before sending more data. In one embodiment, the limit is enforced using a token-based bandwidth control. Embodiments are described in which the limit on sent-but-not-acknowledged data varies dynamically based on system conditions. Specifically, each host may monitor its aggregate latency, and increase the limit when latency is low (indicating low-congestion conditions), and decrease the limit when latency is high (indicating high-congestion conditions).

Abstract: Techniques are described that allow each host in a multi-host system to throttle its bandwidth between multiple data nodes without the need to coordinate with the other hosts. Specifically, techniques are described in which a limit is applied to the amount of sent-but-not-acknowledged data a given host may have. If the host has reached the limit, the host must wait for acknowledgements before sending more data. In one embodiment, the limit is enforced using a token-based bandwidth control. Embodiments are described in which the limit on sent-but-not-acknowledged data varies dynamically based on system conditions. Specifically, each host may monitor its aggregate latency, and increase the limit when latency is low (indicating low-congestion conditions), and decrease the limit when latency is high (indicating high-congestion conditions).