README
¶
Cassandra Resources
Consulting Notes
- 200k column max per partition key (not the technical maximum but a rule of thumb max)
- Beware seconary indexes - understand how they're implemented if you really want to use them
- Beware "batch" writes, rather use a driver that is token aware (reads/writes directly to a node that owns the data) and round robins (shares the read/write load between replicas)
- Use prepared statements
- SSL between cassandra nodes has a large impact on performance
- Use
nodetool histogramsto check on table performance - When you typically serve queries that read from more than 2 sstables, that's usually a problem
- Backfilling is not possible with DTCS, must insert data roughly in time order for sstable compaction to work correctly.
- Avoid gzip table compression, favor snappy and tune it to levels that make sense
- Enterprise in-memory table is sold by DataStax
- Look into cql tracing. At the driver you can specify to explain the query path and details. Many drivers you can configure cql tracing as a probability (e.g. trace 0.1% of queries)
- Any write creates data, even if you're overwriting the same value. Old values are tombstoned and cleaned up on memtable flush or sstable compaction.
Online Resources
The SSTable File http://www.scylladb.com/kb/sstable-data-file/
Compaction strategies http://www.scylladb.com/kb/compaction/
DateTieredCompactionStrategy: Notes From the Field http://www.datastax.com/dev/blog/dtcs-notes-from-the-field
Apache Cassandra Compaction Strategies https://www.instaclustr.com/blog/2016/01/27/apache-cassandra-compaction/
Visualization on Compaction https://labs.spotify.com/2014/12/18/date-tiered-compaction/
DateTieredCompactionStrategy: Compaction for Time Series Data http://www.datastax.com/dev/blog/datetieredcompactionstrategy
Understanding the Impact of Cassandra Compact Storage http://blog.librato.com/posts/cassandra-compact-storage
Documentation
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Overview ¶
Package cassandra implements vulcan storage interfaces for persisting and reading datapoints.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func SetupTables ¶
SetupTables sets up the provided keyspace and creates table `uncompressed` on the provided Cassandra hosts.
Types ¶
type DatapointReader ¶
type DatapointReader struct {
// contains filtered or unexported fields
}
DatapointReader represents an object that queries on the target Cassandra server and transforms the result to a Vulcan Datapoint.
func NewDatapointReader ¶
func NewDatapointReader(config *DatapointReaderConfig) (*DatapointReader, error)
NewDatapointReader creates a new instance of DatapointReader.
func (*DatapointReader) ReadDatapoints ¶
func (dpr *DatapointReader) ReadDatapoints(fqmn string, after, before bus.Timestamp) ([]bus.Datapoint, error)
ReadDatapoints implements storage.DatapointReader interface.
type DatapointReaderConfig ¶
DatapointReaderConfig represents the configuration of a DatapointReader.
type SampleWriter ¶
type SampleWriter struct {
// contains filtered or unexported fields
}
SampleWriter represents an object that writes bus messages to the target Cassandra database.
func NewSampleWriter ¶
func NewSampleWriter(config *SampleWriterConfig) (*SampleWriter, error)
NewSampleWriter creates a new instance of SampleWriter.
func (*SampleWriter) WriteSample ¶
func (sw *SampleWriter) WriteSample(s *bus.Sample) error
WriteSample implements the storage.WriteSample interface.
Source Files