"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)
When we recreate the summary from a missing Summary, we should make
sure it is generated sanely, and that it resembles the Summary that
would have otherwise been there.
In this tests we'll grab one of the Summary tests we've been doing,
and just apply them to the non-existent Summary file. We expect
the same results on those cases. Plus, a new test is added with some
sanity checking.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
This is even a more elaborate tombstone merging unit test, with
3 levels of nesting, which did not pass with older range-tombstone
merging algorithms, and works with the current one.
I started with deletion of three nested levels of row -
aaa, aaa:bbb, and aaa:bbb::ccc. I then complicated the sstable
even further by adding additional middle-points with the same
timestamps (which we saw happening in some real-life sstables),
resulting in:
[
{"key": "pk",
"cells": [["aaa:_","aaa:bba:_",1459438519943668,"t",1459438519],
["aaa:bba:_","aaa:bbb:_",1459438519943668,"t",1459438519],
["aaa:bbb:_","aaa:bbb:ccb:_",1459438519950348,"t",1459438519],
["aaa:bbb:ccb:_","aaa:bbb:ccc:_",1459438519950348,"t",1459438519],
["aaa:bbb:ccc:_","aaa:bbb:ccc:!",1459438519958850,"t",1459438519],
["aaa:bbb:ccc:!","aaa:bbb:ddd:!",1459438519950348,"t",1459438519],
["aaa:bbb:ddd:!","aaa:bbb:!",1459438519950348,"t",1459438519],
["aaa:bbb:!","aaa:!",1459438519943668,"t",1459438519]]}
]
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <1459778074-10759-3-git-send-email-nyh@scylladb.com>
This is another unit test for range tombstone merging, introduced in commit
0fc9a5ee4d and rewritten in commit
99ecda3c96.
In this test, a single large deletion was broken up into several smaller
ranges, all with the same time stamps, so we should recombine them into
one row tombstone, instead of failing the read.
The sstable in this test case was artificially created using json2sstable.
We don't know how yet to produce such a case using Cassandra 2, but we
have seen a similar occurance in the wild, in a real SSTable.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <1459429243-15821-1-git-send-email-nyh@scylladb.com>
Until recently, we believed that range tombstones we read from sstables will
always be for entire rows (or more generalized clustering-key prefixes),
not for arbitrary ranges. But as we found out, because Cassandra insists
that range tombstones do not overlap, it may take two overlapping row
tombstones and convert them into three range tombstones which look like
general ranges (see the patch for a more detailed example).
Not only do we need to accept such "split" range tombstones, we also need
to convert them back to our internal representation which, in the above
example, involves two overlapping tombstones. This is what this patch does.
This patch also contains a test for this case: We created in Cassandra
an sstable with two overlapping deletions, and verify that when we read
it to Scylla, we get these two overlapping deletions - despite the
sstable file actually having contained three non-overlapping tombstones.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <b7c07466074bf0db6457323af8622bb5210bb86a.1459399004.git.glauber@scylladb.com>
This patch tests that collection within a mutation behave properly.
That is what lead to #188.
Signed-off-by: Glauber Costa <glommer@cloudius-systems.com>
