Paimon Metrics #
Paimon has built a metrics system to measure the behaviours of reading and writing, like how many manifest files it scanned in the last planning, how long it took in the last commit operation, how many files it deleted in the last compact operation.
In Paimon’s metrics system, metrics are updated and reported at different levels of granularity. Currently, the levels of table and bucket are provided, which means you can get metrics per table or bucket.
There are three types of metrics provided in the Paimon metric system, Gauge, Counter, Histogram.
Gauge: Provides a value of any type at a point in time.Counter: Used to count values by incrementing and decrementing.Histogram: Measure the statistical distribution of a set of values including the min, max, mean, standard deviation and percentile.
Paimon has supported built-in metrics to measure operations of commits, scans, writes and compactions, which can be bridged to any computing engine that supports, like Flink, Spark etc.
Metrics List #
Below is lists of Paimon built-in metrics. They are summarized into types of scan metrics, commit metrics, write metrics, write buffer metrics and compaction metrics.
Scan Metrics #
| Metrics Name | Level | Type | Description |
|---|---|---|---|
| lastScanDuration | Table | Gauge | The time it took to complete the last scan. |
| scanDuration | Table | Histogram | Distributions of the time taken by the last few scans. |
| lastScannedManifests | Table | Gauge | Number of scanned manifest files in the last scan. |
| lastSkippedByPartitionAndStats | Table | Gauge | Skipped table files by partition filter and value / key stats information in the last scan. |
| lastSkippedByBucketAndLevelFilter | Table | Gauge | Skipped table files by bucket, bucket key and level filter in the last scan. |
| lastSkippedByWholeBucketFilesFilter | Table | Gauge | Skipped table files by bucket level value filter (only primary key table) in the last scan. |
| lastScanSkippedTableFiles | Table | Gauge | Total skipped table files in the last scan. |
| lastScanResultedTableFiles | Table | Gauge | Resulted table files in the last scan. |
Commit Metrics #
| Metrics Name | Level | Type | Description |
|---|---|---|---|
| lastCommitDuration | Table | Gauge | The time it took to complete the last commit. |
| commitDuration | Table | Histogram | Distributions of the time taken by the last few commits. |
| lastCommitAttempts | Table | Gauge | The number of attempts the last commit made. |
| lastTableFilesAdded | Table | Gauge | Number of added table files in the last commit, including newly created data files and compacted after. |
| lastTableFilesDeleted | Table | Gauge | Number of deleted table files in the last commit, which comes from compacted before. |
| lastTableFilesAppended | Table | Gauge | Number of appended table files in the last commit, which means the newly created data files. |
| lastTableFilesCommitCompacted | Table | Gauge | Number of compacted table files in the last commit, including compacted before and after. |
| lastChangelogFilesAppended | Table | Gauge | Number of appended changelog files in last commit. |
| lastChangelogFileCommitCompacted | Table | Gauge | Number of compacted changelog files in last commit. |
| lastGeneratedSnapshots | Table | Gauge | Number of snapshot files generated in the last commit, maybe 1 snapshot or 2 snapshots. |
| lastDeltaRecordsAppended | Table | Gauge | Delta records count in last commit with APPEND commit kind. |
| lastChangelogRecordsAppended | Table | Gauge | Changelog records count in last commit with APPEND commit kind. |
| lastDeltaRecordsCommitCompacted | Table | Gauge | Delta records count in last commit with COMPACT commit kind. |
| lastChangelogRecordsCommitCompacted | Table | Gauge | Changelog records count in last commit with COMPACT commit kind. |
| lastPartitionsWritten | Table | Gauge | Number of partitions written in the last commit. |
| lastBucketsWritten | Table | Gauge | Number of buckets written in the last commit. |
Write Metrics #
| Metrics Name | Level | Type | Description |
|---|---|---|---|
| writeRecordCount | Bucket | Counter | Total number of records written into the bucket. |
| flushCostMillis | Bucket | Histogram | Distributions of the time taken by the last few write buffer flushing. |
| prepareCommitCostMillis | Bucket | Histogram | Distributions of the time taken by the last few call of `prepareCommit`. |
Write Buffer Metrics #
| Metrics Name | Level | Type | Description |
|---|---|---|---|
| bufferPreemptCount | Table | Gauge | The total number of memory preempted. |
| usedWriteBufferSizeByte | Table | Gauge | Current used write buffer size in byte. |
| totalWriteBufferSizeByte | Table | Gauge | The total write buffer size configured in byte. |
Compaction Metrics #
| Metrics Name | Level | Type | Description |
|---|---|---|---|
| level0FileCount | Bucket | Gauge | The level 0 file count will become larger if asynchronous compaction cannot be done in time. |
| lastCompactionDuration | Bucket | Gauge | The time it took to complete the last compaction. |
| compactionDuration | Bucket | Histogram | Distributions of the time taken by the last few compaction. |
| lastTableFilesCompactedBefore | Bucket | Gauge | Number of deleted files in the last compaction. |
| lastTableFilesCompactedAfter | Bucket | Gauge | Number of added files in the last compaction. |
| lastChangelogFilesCompacted | Bucket | Gauge | Number of changelog files compacted in last compaction. |
| lastRewriteInputFileSize | Bucket | Gauge | Size of deleted files in the last compaction. |
| lastRewriteOutputFileSize | Bucket | Gauge | Size of added files in the last compaction. |
| lastRewriteChangelogFileSize | Bucket | Gauge | Size of changelog files compacted in last compaction. |
Bridging To Flink #
Paimon has implemented bridging metrics to Flink’s metrics system, which can be reported by Flink, and the lifecycle of metric groups are managed by Flink.
Please join the <scope>.<infix>.<metric_name> to get the complete metric identifier when using Flink to access Paimon, metric_name can be got from Metric List.
For example, the identifier of metric lastPartitionsWritten for table word_count in Flink job named insert_word_count is:
localhost.taskmanager.localhost:60340-775a20.insert_word_count.Global Committer : word_count.0.paimon.table.word_count.commit.lastPartitionsWritten.
From Flink Web-UI, go to the committer operator’s metrics, it’s shown as:
0.Global_Committer___word_count.paimon.table.word_count.commit.lastPartitionsWritten.
- Please refer to System Scope to understand Flink
scope- Scan metrics are only supported by Flink versions >= 1.18
| Scope | Infix | |
|---|---|---|
| Scan Metrics | <host>.jobmanager.<job_name> | <source_operator_name>.coordinator. enumerator.paimon.table.<table_name>.scan |
| Commit Metrics | <host>.taskmanager.<tm_id>.<job_name>.<committer_operator_name>.<subtask_index> | paimon.table.<table_name>.commit |
| Write Metrics | <host>.taskmanager.<tm_id>.<job_name>.<writer_operator_name>.<subtask_index> | paimon.table.<table_name>.partition.<partition_string>.bucket.<bucket_index>.writer |
| Write Buffer Metrics | <host>.taskmanager.<tm_id>.<job_name>.<writer_operator_name>.<subtask_index> | paimon.table.<table_name>.writeBuffer |
| Compaction Metrics | <host>.taskmanager.<tm_id>.<job_name>.<writer_operator_name>.<subtask_index> | paimon.table.<table_name>.partition.<partition_string>.bucket.<bucket_index>.compaction |
| Flink Source Metrics | <host>.taskmanager.<tm_id>.<job_name>.<source_operator_name>.<subtask_index> | - |
| Flink Sink Metrics | <host>.taskmanager.<tm_id>.<job_name>.<committer_operator_name>.<subtask_index> | - |
Flink Connector Standard Metrics #
When using Flink to read and write, Paimon has implemented some key standard Flink connector metrics to measure the source latency and output of sink, see FLIP-33: Standardize Connector Metrics. Flink source / sink metrics implemented are listed here.
Source Metrics (Flink) #
| Metrics Name | Level | Type | Description |
|---|---|---|---|
| currentEmitEventTimeLag | Flink Source Operator | Gauge | Time difference between sending the record out of source and file creation. |
| currentFetchEventTimeLag | Flink Source Operator | Gauge | Time difference between reading the data file and file creation. |
Please note that if you specifiedconsumer-idin your streaming query, the level of source metrics should turn into the reader operator, which is behind theMonitoroperator.
Sink Metrics (Flink) #
| Metrics Name | Level | Type | Description |
|---|---|---|---|
| numBytesOut | Table | Counter | The total number of output bytes. |
| numBytesOutPerSecond | Table | Meter | The output bytes per second. |
| numRecordsOut | Table | Counter | The total number of output records. |
| numRecordsOutPerSecond | Table | Meter | The output records per second. |