mirror of
https://github.com/scylladb/scylladb.git
synced 2026-05-28 10:41:12 +00:00
dcd2b85e02
When we are about to write a new sstable, we check if the sstable exists by checking if respective TOC exists. That check was added to handle a possible attempt to write a new sstable with a generation being used. Gleb was worried that a TOC could appear after the check, and that's indeed possible if there is an ongoing sstable write that uses the same generation (running in parallel). If TOC appear after the check, we would again crap an existing sstable with a temporary, and user wouldn't be to boot scylla anymore without manual intervention. Then Nadav proposed the following solution: "We could do this by the following variant of Raphael's idea: 1. create .txt.tmp unconditionally, as before the commit031bf57c1(if we can't create it, fail). 2. Now confirm that .txt does not exist. If it does, delete the .txt.tmp we just created and fail. 3. continue as usual 4. and at the end, as before, rename .txt.tmp to .txt. The key to solving the race is step 1: Since we created .txt.tmp in step 1 and know this creation succeeded, we know that we cannot be running in parallel with another writer - because such a writer too would have tried to create the same file, and kept it existing until the very last step of its work (step 4)." This patch implements the solution described above. Let me also say that the race is theoretical and scylla wasn't affected by it so far. Signed-off-by: Raphael S. Carvalho <raphaelsc@scylladb.com> Message-Id: <ef630f5ac1bd0d11632c343d9f77a5f6810d18c1.1457818331.git.raphaelsc@scylladb.com> (cherry picked from commit0af786f3ea)
#Scylla
##Building Scylla
In addition to required packages by Seastar, the following packages are required by Scylla.
Submodules
Scylla uses submodules, so make sure you pull the submodules first by doing:
git submodule init
git submodule update --recursive
Building and Running Scylla on Fedora
- Installing required packages:
sudo yum install yaml-cpp-devel lz4-devel zlib-devel snappy-devel jsoncpp-devel thrift-devel antlr3-tool antlr3-C++-devel libasan libubsan gcc-c++ gnutls-devel ninja-build ragel libaio-devel cryptopp-devel xfsprogs-devel numactl-devel hwloc-devel libpciaccess-devel libxml2-devel python3-pyparsing
- Build Scylla
./configure.py --mode=release --with=scylla --disable-xen
ninja-build build/release/scylla -j2 # you can use more cpus if you have tons of RAM
- 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
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>
Contributing to Scylla
Do not send pull requests.
Send patches to the mailing list address scylladb-dev@googlegroups.com. Be sure to subscribe.
In order for your patches to be merged, you must sign the Contributor's License Agreement, protecting your rights and ours. See http://www.scylladb.com/opensource/cla/.