Abstract: A repository of key-value data may store a first object value having an internal structure of a hierarchy of sub-objects. The repository may receive a request to modify the first object, expressed as a function, without side effects, of one or more parameters. Values may be assigned to the one or more parameters by mapping from the parameters to locations in the hierarchy of sub-objects. A second object may be formed based on the return value of the function. The first object may be replaced in the repository by the second object.

Abstract: A repository of key-value data may store a first object value having an internal structure of a hierarchy of sub-objects. The repository may receive a request to modify the first object, expressed as a function, without side effects, of one or more parameters. Values may be assigned to the one or more parameters by mapping from the parameters to locations in the hierarchy of sub-objects. A second object may be formed based on the return value of the function. The first object may be replaced in the repository by the second object.

Abstract: One or more computing nodes located in a first region may maintain a first collection of data items. A second set of one or more computing nodes in a second region may maintain a collection of data items that is at least a partial replica of the first collection. Notifications of changes to the first collection may be transmitted, via a broadcast communications channel, to a replication module, which may be included in a client application. The replication module may transmit requests to update the second collection of data based on changes to the first collection. Conflicts may be resolved through a last-write wins policy.

Abstract: A client application may interact with a database service using a data interchange format with limited support for database data types or query representations. A map may be supported in the interchange format as a collection of name-value pairs. A database query may be parsed to form an abstract syntax tree. From the abstract syntax tree, a hierarchy of nested maps may be formed to represent the query, based on schemas mapping from regions of the abstract syntax tree to maps in the interchange format.

Abstract: A repository of key-value data may store a first object value having an internal structure of a hierarchy of sub-objects. The repository may receive a request to modify the first object, expressed as a projection of locations in the object to be updated and a function that, upon evaluation, returns values to be used to update the projected locations of the object. The repository may determine that the locations specified by the projections correspond to non-overlapping regions of the object and, based on the determination, update the object using the results of evaluating the function.

Abstract: A database may store an object comprising a hierarchy of sub-objects. Numeric identifiers may be assigned to names of the sub-objects and used in place of the names when writing the object to storage. Scalar values may be prefixed with length indicators. Collections may be prefixed with counts indicative of the number of elements in the corresponding collection. A portion of the object may be retrieved from storage by traversing a path from the root of the hierarchy to the desired portion. Length and count information may be used to skip over portions of the object during the traversal.

Abstract: A method is provided for protecting an on-line resource using a HIP challenge. The method includes receiving a request to access the on-line resource from a remote client. A HIP challenge is presented to a user associated with the remote client. If a successful response to the HIP challenge is received from the user, a previous response pattern of the user is compared to known response patterns of humans and machines. The user is allowed to access to the on-line resource if the comparison indicates that the user is likely a human.

Abstract: A method for generating one or more human interactive proofs (HIPs) is described herein. A HIP request may be received. One of a plurality of HIP engines may be selected using a randomization algorithm. Each HIP engine may have a distinct algorithm for generating the one or more HIPs. The one or more HIPs may be generated using the one of the plurality of HIP engines.

Abstract: A method is provided for protecting an on-line resource using a HIP challenge. The method includes receiving a request to access the on-line resource from a remote client. A HIP challenge is presented to a user associated with the remote client. If a successful response to the HIP challenge is received from the user, a previous response pattern of the user is compared to known response patterns of humans and machines. The user is allowed to access to the on-line resource if the comparison indicates that the user is likely a human.

Abstract: A method for generating one or more human interactive proofs (HIPs) is described herein. A HIP request may be received. One of a plurality of HIP engines may be selected using a randomization algorithm. Each HIP engine may have a distinct algorithm for generating the one or more HIPs. The one or more HIPs may be generated using the one of the plurality of HIP engines.