5fc66bfabc
CatalogD availability is improving since reading is_active_ no longer requires holding catalog_lock_. However, during a failover scenario, requests may slip into the passive-turn-to-active CatalogD and obtain stale metadata. This patch improves the situation in two steps. First, it adds a new mutex ha_transition_lock_ that must be obtained by AcceptRequest() in HA mode. This mutex protects both CatalogServer::WaitPendingResetStarts() and CatalogServer::UpdateActiveCatalogd(). WaitPendingResetStarts() will only exit and return to AcceptRequest() after the triggered_first_reset_ flag is True (initial metadata reset has completed) or min_catalog_resets_to_serve_ is met. If only the latter happens, request will goes through the Catalog JVM and subsequently blocked by CatalogResetManager.waitOngoingMetadataFetch() until metadata reset has progress beyond requested database/table. Second, it increments numCatalogResetStarts_ on every global reset (Invalidate Metadata) initiated by catalog-server.cc. CatalogServer::MarkPendingMetadataReset() matches this logic to increment min_catalog_resets_to_serve_ before setting triggered_first_reset_ flag to False (consequently waking up TriggerResetMetadata thread). Rename WaitForCatalogReady() to WaitCatalogReadinessForWorkloadManagement() since this wait mechanism is specific to Workload Management initialization and has stricter requirements. Removed CatalogServer::IsActive() since the only call site is replaced with CatalogServer::WaitHATransition(). Testing: Added test_metadata_after_failover_with_delayed_reset and test_metadata_after_failover_with_hms_sync. Change-Id: I370d21319335318e441ec3c3455bac4227803900 Reviewed-on: http://gerrit.cloudera.org:8080/23194 Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com> Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Welcome to Impala
Lightning-fast, distributed SQL queries for petabytes of data stored in open data and table formats.
Impala is a modern, massively-distributed, massively-parallel, C++ query engine that lets you analyze, transform and combine data from a variety of data sources:
- Best of breed performance and scalability.
- Support for data stored in Apache Iceberg, HDFS, Apache HBase, Apache Kudu, Amazon S3, Azure Data Lake Storage, Apache Hadoop Ozone and more!
- Wide analytic SQL support, including window functions and subqueries.
- On-the-fly code generation using LLVM to generate lightning-fast code tailored specifically to each individual query.
- Support for the most commonly-used Hadoop file formats, including Apache Parquet and Apache ORC.
- Support for industry-standard security protocols, including Kerberos, LDAP and TLS.
- Apache-licensed, 100% open source.
More about Impala
The fastest way to try out Impala is a quickstart Docker container. You can try out running queries and processing data sets in Impala on a single machine without installing dependencies. It can automatically load test data sets into Apache Kudu and Apache Parquet formats and you can start playing around with Apache Impala SQL within minutes.
To learn more about Impala as a user or administrator, or to try Impala, please visit the Impala homepage. Detailed documentation for administrators and users is available at Apache Impala documentation.
If you are interested in contributing to Impala as a developer, or learning more about Impala's internals and architecture, visit the Impala wiki.
Supported Platforms
Impala only supports Linux at the moment. Impala supports x86_64 and has experimental support for arm64 (as of Impala 4.0). Impala Requirements contains more detailed information on the minimum CPU requirements.
Supported OS Distributions
Impala runs on Linux systems only. The supported distros are
- Ubuntu 16.04/18.04
- CentOS/RHEL 7/8
Other systems, e.g. SLES12, may also be supported but are not tested by the community.
Export Control Notice
This distribution uses cryptographic software and may be subject to export controls. Please refer to EXPORT_CONTROL.md for more information.
Build Instructions
See Impala's developer documentation to get started.
Detailed build notes has some detailed information on the project layout and build.