What Is New in Elasticsearch 1.7
Elasticsearch 1.7 delivers significant enhancements in aggregation performance, script handling, and cluster stability. This release focuses on making complex queries faster and the overall system more robust for production workloads.
| Category | Key Changes |
|---|---|
| New Features | Scripting language plugins, Doc Value support for aggregations, Groovy as default scripting language |
| Performance | Faster date histograms, reduced memory usage for aggregations, improved query caching |
| Mapping & Analysis | Pattern replace character filter, analysis-icu plugin integration |
| Cluster & Networking | Master election improvements, updated transport protocol, multicast discovery enhancements |
| Bug Fixes | Numerous fixes across search, indexing, and recovery processes |
How did scripting change in 1.7?
Scripting got a major overhaul with the introduction of pluggable language modules. Groovy is now the new default and secure scripting engine, replacing the previous MVEL implementation.
This change matters because it provides better security controls and sandboxing out of the box. You can now
explicitly enable or disable specific scripting languages through the script.engine.* settings in
the elasticsearch.yml config file.
In practice, this means your existing scripts might need to be updated if they were written in MVEL. The new plugin architecture also opens the door for using other languages like JavaScript or Python through community modules.
What aggregation improvements were made?
Aggregations are now significantly faster, especially for large datasets, due to the use of Doc Values. This is a big deal for analytics workloads where performance is critical.
The date histogram aggregation saw specific optimizations for time-based data. You'll notice lower memory usage and faster response times when bucketing events over time, which is a common pattern for logging and monitoring use cases.
Query caching also got smarter. The system now does a better job reusing cached results, reducing the load on your cluster for repeated queries.
Were there any mapping or analysis upgrades?
Yes, the new pattern replace character filter allows for powerful text manipulation during analysis. You can now use regex patterns to replace or modify text before it gets indexed.
The analysis-icu plugin is now integrated, providing better internationalization support. This is crucial for handling text in various languages, especially for stemming and collation.
These changes give you more control over how your data is processed and searched, which is essential for building relevant search experiences.
How is cluster stability better in 1.7?
Master election reliability was improved to prevent split-brain scenarios and ensure smoother leadership transitions. This is a core improvement that affects every cluster.
The internal transport protocol was updated for better compatibility and efficiency between nodes. Multicast discovery also received fixes to make node discovery more reliable in network-flaky environments.
In practice, these under-the-hood changes mean your cluster should be more resilient to network issues and node failures, leading to fewer unexpected outages.
FAQ
Do I need to rewrite my scripts after upgrading to 1.7?
If you were using MVEL scripts, yes.
Groovy is now the default scripting language. Check the syntax differences and test your scripts before
upgrading a production cluster.
Will my existing aggregations run faster automatically?
Many will, especially if they use
date histograms or work on large datasets. The performance gains come from using Doc Values, which are now the
default for aggregations.
Is it safe to upgrade from 1.6 to 1.7 directly?
Generally yes, but always backup your data
first. Review the breaking changes list, particularly around scripting (MVEL to Groovy) and the updated
transport protocol.
What are Doc Values and why do they matter?
Doc Values are a columnar data structure stored
on disk. They allow for more efficient sorting and aggregations by reducing memory pressure compared to the old
fielddata approach.
Can I still use MVEL for scripting?
No, MVEL support has been completely removed for security
and performance reasons. You must migrate your scripts to Groovy or another supported scripting language plugin.