Databases Reference
In-Depth Information
Table 4.1 Column Family Parameters
Parameter
Default Value
column_type
Standard
compaction_strategy
SizeTieredCompactionStrategy
comparator
BytesType
compare_subcolumns_with
BytesType
dc_local_read_repair_chance
0
gc_grace_seconds
864000 (10 days)
keys_cached
200000
max_compaction_threshold
32
min_compaction_threshold
4
0.1
or
1
(see description below)
read_repair_chance
replicate_on_write
TRUE
0
(disabled by default)
rows_cached
Data partitioning
Data partitioning can be done either by the client library or by any node of the cluster and can be
calculated using different algorithms. There are two native algorithms that are provided with
Cassandra:
●
Random-Partitionner
—a hash-based distribution, where the keys are more equally partitioned
across the different nodes, providing better load balancing. In this partitioning, each row and all
the columns associated with the row key are stored on the same physical node and columns are
sorted based on their name.
●
OrderPreserving-Partitioner
—creates partitions based on the key and data grouped by keys,
which will boost performance of range queries since the query will need to hit lesser number of
nodes to get all the ranges of data.
Data sorting
When defining a column, you can specify how the columns will be sorted when results are returned to
the client. Columns are sorted by the “compare with” type defined on their enclosing column family.
You can specify a custom sort order; the default provided options are:
●
BytesType—simple sort by byte value; no validation is performed.
●
AsciiType—similar to BytesType, but validates that the input can be parsed as US-ASCII.
●
UTF8Type—a string encoded as UTF8.
●
LongType— 64 bits long.
●
LexicalUUIDType—a 128-bit, compared lexically (by byte value).
●
TimeUUIDType—a 128-bit version 1 University Unique Identifiers (UUID), compared by
timestamp.
●
Integer—faster than a log, and supports fewer or longer lengths.
