CombinedDatastore
Datastore to combine data read from multiple underlying datastores
Description
Use aCombinedDatastore
object to combine the data read from multiple other datastores.
ACombinedDatastore
maintains parity between the underlying datastores, so that data is read from corresponding parts of the underlying datastores. Resetting theCombinedDatastore
resets all of the underlying datastores.
Creation
You can create aCombinedDatastore
object using thecombine
function. For example,dsnew = combine(ds1,ds2)
creates a datastore that combines the read data from datastoresds1
和ds2
.
Properties
Object Functions
combine |
Combine data from multiple datastores |
hasdata |
Determine if data is available to read |
preview |
Preview subset of data in datastore |
read |
Read data in datastore |
readall |
Read all data in datastore |
writeall |
Write datastore to files |
reset |
Reset datastore to initial state |
转换 |
Transform datastore |
numpartitions |
Number of datastore partitions |
partition |
分区数据存储 |
shuffle |
Shuffle all data in datastore |
isPartitionable |
确定数据存储是否可以分区 |
isShuffleable |
Determine whether datastore is shuffleable |