Abstract: The present teaching relates to a method, system and programming for recovering a data storage. In response to a failure of the data storage, a last checkpointed version is retrieved from a checkpoint file created previously for the failure of the data storage. A recovery table is updated to indicate the last checkpointed version and an incarnation number indicating a number of previous recovery of the data storage. The data storage is recovered based on the recovery table. A version number of the last checkpointed version is reset to zero upon a successful recovery of the data storage. The incarnation number is incremented.

Abstract: The present teaching relates to a method, system and programming for operating a data storage. The data storage comprises of different portions including: a first portion having a plurality of metadata objects stored therein, each of the metadata objects being associated with a filter and corresponding to a range of keys, wherein at least one of the metadata objects is associated with a data structure, and a second portion having a plurality of files stored therein, each of the plurality of files being associated with one of the plurality of metadata objects; The data storage synchronizes a scan request with respect to one or more write requests based on a parameter associated with the scan request and each of the one or more write requests.

Abstract: The present teaching relates to a method, system and programming for recovering a data storage. In response to a failure of the data storage, a last checkpointed version is retrieved from a checkpoint file created previously for the failure of the data storage. A recovery table is updated to indicate the last checkpointed version and an incarnation number indicating a number of previous recovery of the data storage. The data storage is recovered based on the recovery table. A version number of the last checkpointed version is reset to zero upon a successful recovery of the data storage. The incarnation number is incremented.

Abstract: The present teaching relates to a method, system and programming for searching a data storage. A key is extracted from a request and a metadata object associated with the key is identified. Further, a determination is made as to whether the metadata object is associated with a data structure stored in a first portion of the data storage. In response to a successful determination, the data structure is searched to retrieve a value associated with the key from the first portion. In response to an unsuccessful determination, a cache is searched to retrieve the value associated with the key, and in response to the key being absent in the cache, a file associated with the metadata object is searched to retrieve the value associated with the key, wherein the file is stored in a second portion of the data storage.

Abstract: The present teaching relates to a method, system and programming for operating a data storage. The data storage comprises of different portions including: a first portion having a plurality of metadata objects stored therein, each of the metadata objects being associated with a filter and corresponding to a range of keys, wherein at least one of the metadata objects is associated with a data structure, and a second portion having a plurality of files stored therein, each of the plurality of files being associated with one of the plurality of metadata objects; The data storage synchronizes a scan request with respect to one or more write requests based on a parameter associated with the scan request and each of the one or more write requests.

Abstract: The present teaching relates to concurrent database operation. In one example, a plurality of requests which includes a scan request to obtain first data associated with a plurality of first keys stored in a database is received concurrently. A global version number is updated upon receipt of the scan request. The first data associated with the plurality of first keys is obtained based on the updated global version number. The first data is provided in response to the scan request.

Abstract: The present teaching relates to a method, system and programming for operating a data storage. The data storage comprises of different portions including: a first portion having a plurality of metadata objects stored therein, each of the metadata objects being associated with a filter and corresponding to a range of keys, wherein at least one of the metadata objects is associated with a data structure, and a second portion having a plurality of files stored therein, each of the plurality of files being associated with one of the plurality of metadata objects; The data storage synchronizes a scan request with respect to one or more write requests based on a parameter associated with the scan request and each of the one or more write requests.

Abstract: Methods, systems, and programming for accessing data are described herein. In a non-limiting embodiment, a request associated with a key may be received. A memory chunk in a first memory site associated with the key may be located. An entry in the memory chunk corresponding to the key may be determined. A first pointer to the key corresponding to a first location of the key within a buffer at a second memory site may be obtained from the entry. The key stored at the first location may be retrieved from the buffer at the second memory site.

Abstract: The present teaching relates to a method, system and programming for searching a data storage. A key is extracted from a request and a metadata object associated with the key is identified. Further, a determination is made as to whether the metadata object is associated with a data structure stored in a first portion of the data storage. In response to a successful determination, the data structure is searched to retrieve a value associated with the key from the first portion. In response to an unsuccessful determination, a cache is searched to retrieve the value associated with the key, and in response to the key being absent in the cache, a file associated with the metadata object is searched to retrieve the value associated with the key, wherein the file is stored in a second portion of the data storage.

Abstract: The present teaching relates to a method, system and programming for operating a data storage. The data storage comprises of different portions including: a first portion having a plurality of metadata objects stored therein, each of the metadata objects being associated with a filter and corresponding to a range of keys, wherein at least one of the metadata objects is associated with a data structure, and a second portion having a plurality of files stored therein, each of the plurality of files being associated with one of the plurality of metadata objects; The data storage synchronizes a scan request with respect to one or more write requests based on a parameter associated with the scan request and each of the one or more write requests.

Abstract: Methods, systems, and programming for accessing data are described herein. In a non-limiting embodiment, a request associated with a key may be received. A memory chunk in a first memory site associated with the key may be located. An entry in the memory chunk corresponding to the key may be determined. A first pointer to the key corresponding to a first location of the key within a buffer at a second memory site may be obtained from the entry. The key stored at the first location may be retrieved from the buffer at the second memory site.

Abstract: The present teaching relates to concurrent database operation. In one example, a plurality of requests which includes a scan request to obtain first data associated with a plurality of first keys stored in a database is received concurrently. A global version number is updated upon receipt of the scan request. The first data associated with the plurality of first keys is obtained based on the updated global version number. The first data is provided in response to the scan request.

Abstract: A method of selecting a target volume in a storage system is provided. The method comprises defining one or more parameters for a plurality of storage volumes in the storage system according to user preference; dynamically collecting information related to the parameters while the storage volumes are used; receiving a request to backup a first source volume in the storage system; and selecting or creating the target volume based on the collected information.

Abstract: Automatic Selection of Storage Volumes in a Data Storage System A method of selecting a target volume in a storage system is provided. The method comprises defining one or more parameters for a plurality of storage volumes in the storage system according to user preference; dynamically collecting information related to the parameters while the storage volumes are used; receiving a request to backup a first source volume in the storage system; and selecting or creating the target volume based on the collected information.