Apache Solr Orbit includes telemetry devices for collecting server-side metrics. Six devices are always enabled and collect metrics automatically without any flags. One additional device (disk-io) runs automatically on provisioned pipelines. Eight further devices can be enabled on demand with --telemetry.
Both Solr 9.x (JSON format) and Solr 10.x (Prometheus text format) are supported. Format detection is automatic via the HTTP Content-Type header.
Collects JVM statistics from each Solr node via the Solr metrics API.
Always active. No --telemetry flag required.
Metrics collected:
| Metric | Unit | Description |
|---|---|---|
jvm_heap_used_bytes | bytes | JVM heap memory currently used |
jvm_heap_max_bytes | bytes | Maximum JVM heap size |
jvm_gc_count | count | Total GC collections across all collectors |
jvm_gc_time_ms | ms | Total GC wall time across all collectors |
jvm_gc_young_count | count | Young-generation GC collection count |
jvm_gc_young_time_ms | ms | Young-generation GC wall time |
jvm_gc_old_count | count | Old-generation GC collection count |
jvm_gc_old_time_ms | ms | Old-generation GC wall time |
jvm_thread_count | count | Current JVM thread count |
jvm_thread_peak_count | count | Peak JVM thread count since startup |
jvm_buffer_pool_direct_bytes | bytes | Direct byte buffer pool memory used |
jvm_buffer_pool_mapped_bytes | bytes | Memory-mapped buffer pool memory used |
Collects Solr node-level and OS statistics.
Always active. No --telemetry flag required.
Metrics collected:
| Metric | Unit | Description |
|---|---|---|
cpu_usage_percent | % | Process CPU load (0–100) |
os_memory_free_bytes | bytes | Free physical OS memory |
node_file_descriptors_open | count | Currently open file descriptors |
node_file_descriptors_max | count | Maximum allowed file descriptors |
node_http_requests_total | count | Total HTTP requests processed by Jetty |
query_handler_requests_total | count | Total /select query handler requests |
query_handler_errors_total | count | Total /select query handler errors |
query_handler_avg_latency_ms | ms | Rolling average /select request latency |
Collects per-collection document count, segment count, and deleted doc count.
Always active. No --telemetry flag required.
Metrics collected (all tagged with collection metadata):
| Metric | Unit | Description |
|---|---|---|
num_docs | docs | Current document count |
num_deleted_docs | docs | Number of deleted (soft-deleted) documents |
segment_count | count | Number of Lucene segments |
index_size_bytes | bytes | Total index size on disk |
Notes: Collection stats are polled every 30 seconds by default. Override with --telemetry-params collection-stats-sample-interval:60. Uses both the Collections API and the Luke request handler (/admin/luke) for full statistics.
Collects query latency percentiles and filter cache hit ratio.
Always active. No --telemetry flag required.
Metrics collected:
| Metric | Unit | Description |
|---|---|---|
query_latency_p50_ms | ms | 50th percentile /select request latency |
query_latency_p99_ms | ms | 99th percentile /select request latency |
query_latency_p999_ms | ms | 99.9th percentile /select request latency |
query_requests_total | count | Total /select handler request count |
query_errors_total | count | Total /select handler error count |
query_cache_hit_ratio | ratio | Filter cache hit ratio (0.0–1.0) |
Collects update handler and merge metrics.
Always active. No --telemetry flag required.
Metrics collected:
| Metric | Unit | Description |
|---|---|---|
indexing_requests_total | count | Total /update handler requests |
indexing_errors_total | count | Total /update handler errors |
indexing_avg_time_ms | ms | Rolling average /update request time |
index_merge_major_running | count | Currently running major merges |
index_merge_minor_running | count | Currently running minor merges |
Collects hit/miss/eviction and memory statistics for the three primary Solr caches.
Always active. No --telemetry flag required.
Metrics collected (all tagged with cache metadata: queryResultCache, filterCache, documentCache):
| Metric | Unit | Description |
|---|---|---|
cache_hits_total | count | Cache hits since Solr start |
cache_inserts_total | count | Cache inserts since Solr start |
cache_evictions_total | count | Cache evictions since Solr start |
cache_memory_bytes | bytes | RAM used by this cache |
cache_hit_ratio | ratio | Hit ratio (0.0–1.0) |
The following device activates automatically when using the docker or from-distribution pipeline. It cannot be disabled and does not need to be listed in --telemetry.
Measures disk I/O consumed by the Solr process during the benchmark run.
Pipeline: docker or from-distribution (always active; not available on benchmark-only)
| Metric | Unit | Description |
|---|---|---|
disk_io_read_bytes | bytes | Bytes read by the Solr process |
disk_io_write_bytes | bytes | Bytes written by the Solr process |
Optional devices must be explicitly requested with --telemetry <name>. REST-based optional devices work with all pipelines. JVM/process devices inject flags into SOLR_OPTS before Solr starts and require the docker or from-distribution pipeline — they are silently skipped on benchmark-only.
Captures per-collection segment statistics via the Solr Luke request handler.
Pipeline: All pipelines Enable: --telemetry segment-stats
Collected on benchmark stop. Results are written to segment_stats.log in the benchmark log directory.
| Metric (in log file) | Description |
|---|---|
numDocs | Current document count |
maxDoc | Maximum doc ID (includes deleted docs) |
deletedDocs | Number of soft-deleted documents |
segmentCount | Number of Lucene segments |
sizeInBytes | Total index size on disk |
Polls CLUSTERSTATUS and Core STATUS for each shard leader and records per-shard metrics. Skipped silently on standalone (non-SolrCloud) Solr.
Pipeline: All pipelines Enable: --telemetry shard-stats
| Metric | Unit | Description |
|---|---|---|
shard_{name}_num_docs | count | Document count for the named shard |
shard_{name}_size_bytes | bytes | Index size for the named shard |
The default poll interval is 60 seconds. Override with --telemetry-params shard-stats-sample-interval:30.
Records Solr version, JVM version, and hardware info as run metadata. Called once at benchmark start.
Pipeline: All pipelines Enable: --telemetry cluster-environment-info
| Metadata key | Description |
|---|---|
distribution_version | Solr version string (e.g. 9.7.0) |
jvm_version | JVM version (e.g. 21.0.1) |
jvm_vendor | JVM vendor name (e.g. OpenJDK 21) |
cpu_logical_cores | Number of logical CPU cores on the node |
cluster_node_count | Number of live SolrCloud nodes |
Enables Java Flight Recorder. Injects -XX:StartFlightRecording=... into SOLR_OPTS.
Pipeline: docker or from-distribution only Enable: --telemetry jfr
The flight recording is written to profile.jfr in the benchmark log directory. Requires OpenJDK 11 or later. To use a custom recording template, pass --telemetry-params recording-template:/path/to/template.jfc.
Enables GC logging (Java 9+ -Xlog: format). Injects the GC log flags into SOLR_OPTS.
Pipeline: docker or from-distribution only Enable: --telemetry gc
GC output is written to gc.log in the benchmark log directory. The default log configuration is gc*=info,safepoint=info,age*=trace. Override with --telemetry-params gc-log-config:gc*=debug.
Enables JIT compiler logging. Injects -XX:+LogCompilation and related flags into SOLR_OPTS.
Pipeline: docker or from-distribution only Enable: --telemetry jit
JIT output is written to jit.log in the benchmark log directory.
Captures a heap dump (jmap -dump) from the Solr JVM when the benchmark finishes.
Pipeline: docker or from-distribution only Enable: --telemetry heapdump
The heap dump is written to heap_at_exit_{pid}.hprof in the benchmark log directory. On Docker pipelines, docker exec is used automatically.
The six always-on devices collect metrics automatically — no flags required:
# Always-on devices activate without any --telemetry flag: solr-orbit run \ --pipeline benchmark-only \ --target-hosts localhost:8983 \ --workload nyc_taxis
Add optional REST devices on any pipeline:
solr-orbit run \ --pipeline benchmark-only \ --target-hosts localhost:8983 \ --workload nyc_taxis \ --telemetry segment-stats,shard-stats,cluster-environment-info
Add JVM profiling devices on provisioned pipelines:
solr-orbit run \ --pipeline docker \ --distribution-version 9.10.1 \ --workload nyc_taxis \ --telemetry gc,jfr
Telemetry metrics are written to the metrics store alongside all other benchmark metrics. When using the filesystem store, they are recorded in metrics.jsonl in the test run directory (~/.solr-orbit/benchmarks/test-runs/<run-id>/). See Filesystem Metrics Store for the file format.