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Affects single-partition reads only. Refs #5113 When executing a query on the replica we do several things in order to narrow down the sstable set we read from. For tables which use LeveledCompactionStrategy, we store sstables in an interval set and we select only sstables whose partition ranges overlap with the queried range. Other compaction strategies don't organize the sstables and will select all sstables at this stage. The reasoning behind this is that for non-LCS compaction strategies the sstables' ranges will typically overlap and using interval sets in this case would not be effective and would result in quadratic (in sstable count) memory consumption. The assumption for overlap does not hold if the sstables come from repair or streaming, which generates non-overlapping sstables. At a later stage, for single-partition queries, we use the sstables' bloom filter (kept in memory) to drop sstables which surely don't contain given partition. Then we proceed to sstable indexes to narrow down the data file range. Tables which don't use LCS will do unnecessary I/O to read index pages for single-partition reads if the partition is outside of the sstable's range and the bloom filter is ineffective (Refs #5112). This patch fixes the problem by consulting sstable's partition range in addition to the bloom filter, so that the non-overlapping sstables will be filtered out with certainty and not depend on bloom filter's efficiency. It's also faster to drop sstables based on the keys than the bloom filter. Tests: - unit (dev) - manual using cqlsh Reviewed-by: Botond Dénes <bdenes@scylladb.com> Message-Id: <20190927122505.21932-1-tgrabiec@scylladb.com>
Scylla
Quick-start
To get the build going quickly, Scylla offers a frozen toolchain which would build and run Scylla using a pre-configured Docker image. Using the frozen toolchain will also isolate all of the installed dependencies in a Docker container. Assuming you have met the toolchain prerequisites, which is running Docker in user mode, building and running is as easy as:
$ ./tools/toolchain/dbuild ./configure.py
$ ./tools/toolchain/dbuild ninja build/release/scylla
$ ./tools/toolchain/dbuild ./build/release/scylla --developer-mode 1
Please see HACKING.md for detailed information on building and developing Scylla.
Note: GCC >= 8.1.1 is required to compile Scylla.
Running Scylla
- Run Scylla
./build/release/scylla
- run Scylla with one CPU and ./tmp as data directory
./build/release/scylla --datadir tmp --commitlog-directory tmp --smp 1
- For more run options:
./build/release/scylla --help
Scylla APIs and compatibility
By default, Scylla is compatible with Apache Cassandra and its APIs - CQL and Thrift. There is also experimental support for the API of Amazon DynamoDB, but being experimental it needs to be explicitly enabled to be used. For more information on how to enable the experimental DynamoDB compatibility in Scylla, and the current limitations of this feature, see Alternator and Getting started with Alternator.
Building Fedora RPM
As a pre-requisite, you need to install Mock on your machine:
# Install mock:
sudo yum install mock
# Add user to the "mock" group:
usermod -a -G mock $USER && newgrp mock
Then, to build an RPM, run:
./dist/redhat/build_rpm.sh
The built RPM is stored in /var/lib/mock/<configuration>/result directory.
For example, on Fedora 21 mock reports the following:
INFO: Done(scylla-server-0.00-1.fc21.src.rpm) Config(default) 20 minutes 7 seconds
INFO: Results and/or logs in: /var/lib/mock/fedora-21-x86_64/result
Building Fedora-based Docker image
Build a Docker image with:
cd dist/docker
docker build -t <image-name> .
Run the image with:
docker run -p $(hostname -i):9042:9042 -i -t <image name>