"The goal of this patch series is to support reading and writing of a
"promoted index" - the Cassandra 2.* SSTable feature which allows reading
only a part of the partition without needing to read an entire partition
when it is very long. To make a long story short, a "promoted index" is
a sample of each partition's column names, written to the SSTable Index
file with that partition's entry. See a longer explanation of the index
file format, and the promoted index, here:
https://github.com/scylladb/scylla/wiki/SSTables-Index-File
There are two main features in this series - first enabling reading of
parts of partitions (using the promoted index stored in an sstable),
and then enable writing promoted indexes to new sstables. These two
features are broken up into smaller stand-alone pieces to facilitate the
review.
Three features are still missing from this series and are planned to be
developed later:
1. When we fail to parse a partition's promoted index, we silently fall back
to reading the entire partition. We should log (with rate limiting) and
count these errors, to help in debugging sstable problems.
2. The current code only uses the promoted index when looking for a single
contiguous clustering-key range. If the ck range is non-contiguous, we
fall back to reading the entire partition. We should use the promoted
index in that case too.
3. The current code only uses the promoted index when reading a single
partition, via sstable::read_row(). When scanning through all or a
range of partitions (read_rows() or read_range_rows()), we do not yet
use the promoted index; We read contiguously from data file (we do not
even read from the index file, so unsurprisingly we can't use it)."
(cherry picked from commit 700feda0db)
range_tombstone::flip() flips range bounds. This is necessary in order
to use range tombstone in reversed mutation fragment streams.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
range_tombstone_accumulator is a helper class that allows determining
tombstone for a clustering row when range tombstones and clustering rows
are streamed from streamed_mutation.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
range_tombstone::apply() allows merging two, possibly overlapping, range
tombstones with the same start bound and produces one or two disjoint
range tombstones as a result.
It is intended to be used for merging tombstones coming from different
sources.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
flip_bound_kind() changes start bound to end bound and vice versa while
preserving the inclusivness.
Signed-off-by: Paweł Dziepak <pdziepak@scylladb.com>
This patch introduces the range_tombstone class, composed of
a [start, end] pair of clustering_key_prefixes, the type
of inclusiveness of each bound, and a tombstone.
Signed-off-by: Duarte Nunes <duarte@scylladb.com>
