BlockInfo — Metadata of Memory Block
BlockInfo
is a metadata of memory block (aka memory page) — the memory block’s size, the number of readers and the id of the writer task.
BlockInfo
has a StorageLevel, ClassTag
and tellMaster
flag.
Size — size
Attribute
size
attribute is the size of the memory block. It starts with 0
.
It represents the number of bytes that BlockManager
saved or BlockManager.doPutIterator.
Reader Count — readerCount
Counter
readerCount
counter is the number of readers of the memory block, i.e. the number of read locks. It starts with 0
.
readerCount
is incremented when a read lock is acquired and decreases when the following happens: