mirror of
https://github.com/scylladb/scylladb.git
synced 2026-06-09 00:13:31 +00:00
280715ad45
A recent fix to #3767 limited the amount of ranges that can return from query_ranges_to_vnodes_generator. This with the combination of a large amount of token ranges can lead to an infinite recursion. The algorithm multiplies by factor of 2 (actualy a shift left by one) the amount of requested tokens in each recursion iteration. As long as the requested number of ranges is greater than 0, the recursion is implicit, and each call is scheduled separately since the call is inside a continuation of a map reduce. But if the amount of iterations is large enough (~32) the counter for requested ranges zeros out and from that moment on two things will happen: 1. The counter will remain 0 forever (0*2 == 0) 2. The map reduce future will be immediately available and this will result in the continuation being invoked immediately. The latter causes the recursive call to be a "regular" recursive call thus, through the stack and not the task queue of the scheduler, and the former causes this recursion to be infinite. The combination creates a stack that keeps growing and eventually overflows resulting in undefined behavior (due to memory overrun). This patch prevent the problem from happening, it limits the growth of the concurrency counter beyond twice the last amount of tokens returned by the query_ranges_to_vnodes_generator.And also makes sure it is not get stuck at zero. Testing: * Unit test in dev mode. * Modified add 50 dtest that reproduce the problem Fixes #4944 Signed-off-by: Eliran Sinvani <eliransin@scylladb.com> Message-Id: <20190922072838.14957-1-eliransin@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>