Abstract: Examples of the disclosure describe systems and methods for presenting virtual content on a wearable head device. In some embodiments, a state of a wearable head device is determined by minimizing a total error based on a reduced weight associated with a reprojection error. A view reflecting the determined state of the wearable head device is presented via a display of the wearable head device. In some embodiments, a wearable head device calculates a preintegration term based on the image data received via a sensor of the wearable head device and the inertial data received via a first IMU and a second IMU of the wearable head device. The wearable head device estimates a position of the device based on the preintegration term, and the wearable head device presents the virtual content based on the position of the device.

Abstract: Granular performance analysis may be performed for database queries. Database query performance may be monitored. For some database queries, performance of portions of the database query may be measure. The measure performance of the portions may be compared with performance goals that correspond to the portions of the database query. Portions that do not meet or exceed the corresponding performance goals may be identified so that an indication of the identified portions may be provided.

Abstract: Techniques are described for managing communications between multiple intercommunicating computing nodes, such as multiple virtual machine nodes hosted on one or more physical computing machines or systems. In some situations, users may specify groups of computing nodes and optionally associated access policies for use in the managing of the communications for those groups, such as by specifying which source nodes are allowed to transmit data to particular destinations nodes. In addition, determinations of whether initiated data transmissions from source nodes to destination nodes are authorized may be dynamically negotiated for and recorded for later use in automatically authorizing future such data transmissions without negotiation. This abstract is provided to comply with rules requiring an abstract, and it is submitted with the intention that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A database system may include a database service and a separate distributed storage service. The database service (or a database engine head node thereof) may be responsible for query parsing, optimization, and execution, transactionality, and consistency, while the storage service may be responsible for generating data pages from redo log records and for durability of those data pages. For example, in response to a write request directed to a particular data page, the database engine head node may generate a redo log record and send it, but not the data page, to a storage service node. The storage service node may store the redo log record and return a write acknowledgement to the database service prior to applying the redo log record. The server node may apply the redo log record and other redo log records to a previously stored version of the data page to create a current version.

Abstract: A tree-based format may be implemented for data stored in a data store. A table may be maintained across one or multiple storage nodes in storage slabs. Storage slabs may be mapped to different nodes of a tree. Each node of the tree may be assigned a different range of distribution scheme values which identify what portions of the table are stored in the storage slab. Storage slabs mapped to child nodes in the tree may be assigned portions of the range of distribution scheme values assigned to a parent. Storage nodes may be added or removed for storing the table. Storage slabs may be moved from one storage node to another in order to accommodate the addition or removal of storage nodes.

Abstract: Techniques are described for managing communications between multiple intercommunicating computing nodes, such as multiple virtual machine nodes hosted on one or more physical computing machines or systems. In some situations, users may specify groups of computing nodes and optionally associated access policies for use in the managing of the communications for those groups, such as by specifying which source nodes are allowed to transmit data to particular destinations nodes. In addition, determinations of whether initiated data transmissions from source nodes to destination nodes are authorized may be dynamically negotiated for and recorded for later use in automatically authorizing future such data transmissions without negotiation. This abstract is provided to comply with rules requiring an abstract, and it is submitted with the intention that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A database system may include a database service and a separate distributed storage service. The database service (or a database engine head node thereof) may be responsible for query parsing, optimization, and execution, transactionality, and consistency, while the storage service may be responsible for generating data pages from redo log records and for durability of those data pages. For example, in response to a write request directed to a particular data page, the database engine head node may generate a redo log record and send it, but not the data page, to a storage service node. The storage service node may store the redo log record and return a write acknowledgement to the database service prior to applying the redo log record. The server node may apply the redo log record and other redo log records to a previously stored version of the data page to create a current version.

Abstract: The present disclosure relates to a system and techniques for enabling data to be updated within a data store through concurrent operations. Embodiments of the system enables multiple client applications (e.g., implemented on a cloud platform) to update data concurrently. In some embodiments, operations may be determined to be either client-managed operations or service-managed operations. Client-managed operations may be performed by a client application, whereas the client application may pass service-managed operations to a service application. The service application may put each of the service-managed operations into a commit queue wherein each service-managed operation is committed only after the one put into the queue before it has been committed.

Abstract: The present disclosure relates to a system and techniques for enabling data to be updated within a data store through concurrent operations. Embodiments of the system enables multiple client applications (e.g., implemented on a cloud platform) to update data concurrently. In some embodiments, operations may be determined to be either client-managed operations or service-managed operations. Client-managed operations may be performed by a client application, whereas the client application may pass service-managed operations to a service application. The service application may put each of the service-managed operations into a commit queue wherein each service-managed operation is committed only after the one put into the queue before it has been committed.

Abstract: Techniques are described for managing communications between multiple intercommunicating computing nodes, such as multiple virtual machine nodes hosted on one or more physical computing machines or systems. In some situations, users may specify groups of computing nodes and optionally associated access policies for use in the managing of the communications for those groups, such as by specifying which source nodes are allowed to transmit data to particular destinations nodes. In addition, determinations of whether initiated data transmissions from source nodes to destination nodes are authorized may be dynamically negotiated for and recorded for later use in automatically authorizing future such data transmissions without negotiation. This abstract is provided to comply with rules requiring an abstract, and it is submitted with the intention that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A database system may include a database service and a separate distributed storage service. The database service (or a database engine head node thereof) may be responsible for query parsing, optimization, and execution, transactionality, and consistency, while the storage service may be responsible for generating data pages from redo log records and for durability of those data pages. For example, in response to a write request directed to a particular data page, the database engine head node may generate a redo log record and send it, but not the data page, to a storage service node. The storage service node may store the redo log record and return a write acknowledgement to the database service prior to applying the redo log record. The server node may apply the redo log record and other redo log records to a previously stored version of the data page to create a current version.

Abstract: Techniques are described for managing the execution of programs on multiple computing systems, such as on virtual machine nodes executing on the computing systems. A program execution service may in some situations provide the multiple computing systems and manage the program execution on behalf of multiple customers or other users, including to select appropriate computing systems to execute one or more instances of a program for a user, such as based in part on configuration information specified by the user. The described techniques may further include managing communications between multiple intercommunicating computing nodes in some situations.

Abstract: A database system may include a database service and a separate distributed storage service. The database service (or a database engine head node thereof) may be responsible for query parsing, optimization, and execution, transactionality, and consistency, while the storage service may be responsible for generating data pages from redo log records and for durability of those data pages. For example, in response to a write request directed to a particular data page, the database engine head node may generate a redo log record and send it, but not the data page, to a storage service node. The storage service node may store the redo log record and return a write acknowledgement to the database service prior to applying the redo log record. The server node may apply the redo log record and other redo log records to a previously stored version of the data page to create a current version.

Abstract: A log-structured data store may implement optimized log storage for asynchronous log updates. In some embodiments, log records may be received indicating updates to data stored for a storage client and indicating positions in a log record sequence. The log records themselves may not be guaranteed to be received according to the log record sequence. Received log records may be stored in a hot log portion of a block-based storage device according to an order in which they are received. Log records in the hot log portion may then be identified to be moved to a cold log portion of the block-based storage device in order to complete a next portion of the log record sequence. Log records may be modified, such as compressed, or coalesced, before being stored together in a data block of the cold log portion according to the log record sequence.

Abstract: Techniques are described for managing communications between multiple intercommunicating computing nodes, such as multiple virtual machine nodes hosted on one or more physical computing machines or systems. In some situations, users may specify groups of computing nodes and optionally associated access policies for use in the managing of the communications for those groups, such as by specifying which source nodes are allowed to transmit data to particular destinations nodes. In addition, determinations of whether initiated data transmissions from source nodes to destination nodes are authorized may be dynamically negotiated for and recorded for later use in automatically authorizing future such data transmissions without negotiation. This abstract is provided to comply with rules requiring an abstract, and it is submitted with the intention that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Techniques are described for managing the execution of programs on multiple computing systems, such as on virtual machine nodes executing on the computing systems. A program execution service may in some situations provide the multiple computing systems and manage the program execution on behalf of multiple customers or other users, including to select appropriate computing systems to execute one or more instances of a program for a user, such as based in part on configuration information specified by the user. The described techniques may further include managing communications between multiple intercommunicating computing nodes in some situations.

Abstract: A distributed database system may implement log-structured distributed storage using a single log sequence number space. A log for a data volume may be maintained in a log-structured distributed storage system. The log may be segmented across multiple protection groups according to a partitioning of user data for the data volume. Updates to the log may be assigned a log sequence number from a log sequence number space for the data volume. A protection group may be determined for an update according to which partition of user data space the update pertains. Metadata to be included with the log record may indicate a previous log sequence number of a log record maintained at the protection group. The log record may be sent to the protection group and identified as committed based on acknowledgments received from storage nodes implementing the protection group.

Abstract: A log-structured distributed storage system may implement individual write quorums. Log records may be sent to different storage nodes of a quorum set storing data for a storage client sufficient to satisfy a write quorum requirement. For each log record, acknowledgments from storage nodes are received, and a determination is made whether the write quorum requirement is satisfied for the log record. Different log records may be maintained at different storage nodes, and still satisfy the write quorum requirement such that in some embodiments no one storage node may maintain all of the log records sent to storage nodes in the quorum set.

Abstract: Techniques are described for managing communications between multiple intercommunicating computing nodes, such as multiple virtual machine nodes hosted on one or more physical computing machines or systems. In some situations, users may specify groups of computing nodes and optionally associated access policies for use in the managing of the communications for those groups, such as by specifying which source nodes are allowed to transmit data to particular destinations nodes. In addition, determinations of whether initiated data transmissions from source nodes to destination nodes are authorized may be dynamically negotiated for and recorded for later use in automatically authorizing future such data transmissions without negotiation. This abstract is provided to comply with rules requiring an abstract, and it is submitted with the intention that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A distributed database system may implement log-structured distributed storage using a single log sequence number space. A log for a data volume may be maintained in a log-structured distributed storage system. The log may be segmented across multiple protection groups according to a partitioning of user data for the data volume. Updates to the log may be assigned a log sequence number from a log sequence number space for the data volume. A protection group may be determined for an update according to which partition of user data space the update pertains. Metadata to be included with the log record may indicate a previous log sequence number of a log record maintained at the protection group. The log record may be sent to the protection group and identified as committed based on acknowledgments received from storage nodes implementing the protection group.