Speeding Up Dump & Restore

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Many ArangoDB users rely on our arangodump and arangorestore tools as an integral part of their backup and recovery procedures. As such, we want to make the use of these tools, especially arangodump, as fast as possible. We’ve been working hard toward this goal in preparation for the upcoming 3.4 release.

We’ve made a number of low-level server-side changes to significantly reduce overhead and improve throughput. Additionally, we’ve put some work into rewriting much of the code for the client tools to allow dumping and restoring collections in parallel, using a number of worker threads specified by --threads n. Read more

An implementation of phase-fair reader/writer locks

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We were in search for some C++ reader/writer locks implementation that allows a thread to acquire a lock and then optionally pass it on to another thread. The C++11 and C++14 standard library lock implementations std::mutex and shared_mutex do not allow that (it would be undefined behaviour – by the way, it’s also undefined behaviour when doing this with the pthreads library).

Additionally, we were looking for locks that would neither prefer readers nor writers, so that there will be neither reader starvation nor writer starvation. And then, we wanted concurrently queued read and write requests that compete for the lock to be brought into some defined execution order. Ideally, queued operations that cannot instantly acquire the lock should be processed in approximately the same order in which they queued. Read more

Index types and how indexes are used in ArangoDB: Part II

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In the first part of this article we dived deep into what indexes are currently available in ArangoDB (3.2 and 3.3), also briefly looking at what improvements are coming with ArangoDB 3.4. Read Part I here.

In this Part II, we are going to focus on how to actually add indexes to a data model and speed up specific queries.

Adding indexes to the data model

The goal of adding an extra index to the data model is to speed up a certain query or even multiple queries.

One of the first things that should be done during development of AQL queries should be to review the output of the explain command. A query can be explained using ArangoDB’s WEB UI or from the ArangoShell. In the ArangoShell it is as simple as db._explain(query), where query is the AQL query string. To explain a query which also has bind parameters, they need to be passed separately into the command, e.g. db._explain(query, bindParameters).
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How We Wronged Neo4j & PostgreSQL: Update of ArangoDB Benchmark 2018

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Recently, we published the latest findings of our Performance Benchmark 2018 including Neo4j, PostgGreSQL, MongoDB, OrientDB and, of course, ArangoDB. We tested bread & butter tasks in a client/server setup for all databases like single read/write and aggregation, but also things like shortest path queries which are a speciality for graph databases. Our goal was and is to demonstrate that a native multi-model database like ArangoDB can at least compete with the leading single model databases on their home turf.

Traditionally, we are transparent with our benchmarks, learned plenty from community feedback and want to keep it that way. Unfortunately, we did something wrong in our latest version and this update will explain what happened and how we fixed it. Read more

Index types and how indexes are used in ArangoDB: Part I

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As in other database systems, indexes can be used in ArangoDB to speed up data retrieval queries, sometimes by many orders of magnitude. Getting the indexes set up the right way is essential for good query performance, so this is an important topic that affects most ArangoDB installations.

This is Part I of how indexes are used by ArangoDB where we discuss what types of indexes are available in the database. In Part II, we will dig deeper into how to actually add indexes to a data model and speed up specific queries. Read Part II here. Read more

NoSQL Performance Benchmark 2018 – MongoDB, PostgreSQL, OrientDB, Neo4j and ArangoDB

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ArangoDB, as a native multi-model database, competes with many single-model storage technologies. When we started the ArangoDB project, one of the key design goals was and still is to at least be competitive with the leading single-model vendors on their home turf. Only then does a native multi-model make sense. To prove that we are meeting our goals and are competitive, we run and publish occasionally an update to the benchmark series. This time we included MongoDB, PostgreSQL (tabular & JSONB), OrienDB and Neo4j.
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Performance Impact of Meltdown and Spectre V1 Patches on ArangoDB

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To investigate the impact of the Meltdown and Spectre patches on the performance of ArangoDB, we ran benchmark tests with the two storage engines available in ArangoDB (MMFiles & RocksDB). We used the arangobench benchmark and test tool for these tests.

The tests include 10 different test cases with changing test parameters like concurrency, batch requests and asynchronous execution. Read more

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