#10818: META_LOGICAL_ID is constant which is used to assign a logical id to a special btree node in which btree metadata is stored. This Special node is used during recovery. During creation of each btree node, we refer (take a refcount) this special node and compare if any metadata has changed or not. Whenever there is a change in btree root or some btree related (refer "savepersistent()" funtion for more details), this special node is updated. Irrespective of change in btree metadata related information, we refer this special node during a btree node creation. In cassandra if total number of columns are 'c', each column size is 's' and total number of threads are 't'. Then in worst case at max t * c * (s/(sizeofbtreenode)) times refcount will be taken on this special node at a particular point of time. For example if total number of threads are 50, total number of columns are 40 and size of column is 64k and size of btreenode is 8k, then in worstcase refcount of this special node will be 50 * 40 * (64k/8k) = 16000. In above example 64k/8k denotes overflow data nodes for a key. TESTS_RAN: UnitTests and FDF Dev Tests 2.0.
#10818: META_LOGICAL_ID is constant which is used to assign a logical id to a special btree node in which btree metadata is stored. This Special node is used during recovery. During creation of each btree node, we refer (take a refcount) this special node and compare if any metadata has changed or not. Whenever there is a change in btree root or some btree related (refer "savepersistent()" funtion for more details), this special node is updated. Irrespective of change in btree metadata related information, we refer this special node during a btree node creation. In cassandra if total number of columns are 'c', each column size is 's' and total number of threads are 't'. Then in worst case at max t * c * (s/(sizeofbtreenode)) times refcount will be taken on this special node at a particular point of time. For example if total number of threads are 50, total number of columns are 40 and size of column is 64k and size of btreenode is 8k, then in worstcase refcount of this special node will be 50 * 40 * (64k/8k) = 16000. In above example 64k/8k denotes overflow data nodes for a key.
TESTS_RAN: UnitTests and FDF Dev Tests 2.0.


git-svn-id: 7398c538febd9d5ada4c6b3e78dc2c3acdb8ce2c@1958 01a69087-22d5-4a29-8152-8a1d5e10e5e9

SanDisk-Open-Source/zetascale,SanDisk-Open-Source/zetascale,SanDisk-Open-Source/zetascale,SanDisk-Open-Source/zetascale,SanDisk-Open-Source/zetascale