sanjeet006py commented on code in PR #21:
URL: https://github.com/apache/phoenix-site/pull/21#discussion_r3267857257
##########
app/pages/_docs/docs/_mdx/(multi-page)/features/metrics.mdx:
##########
@@ -117,3 +117,82 @@ service.submit(new Runnable() {
}
});
```
+
+## Scan latency metrics [#scan-latency-metrics]
+
+Phoenix 5.3.1 surfaces HBase's per-scan latency and IO metrics through the
+request-level metrics API, giving per-query visibility into where a scan
+actually spent its time
+([PHOENIX-7704](https://issues.apache.org/jira/browse/PHOENIX-7704)).
+
+| Metric | Description
|
+| ---------------------------- |
----------------------------------------------------------------------- |
+| `FS_READ_TIME` | Time (ms) spent in the underlying filesystem
(HDFS/S3) for HFile reads. |
+| `BYTES_READ_FROM_FS` | Bytes read from the filesystem — cold reads
that missed every cache. |
+| `BYTES_READ_FROM_MEMSTORE` | Bytes read from memstore — un-flushed cells.
|
+| `BYTES_READ_FROM_BLOCKCACHE` | Bytes served from the HBase block cache —
warm reads. |
+| `BLOCK_READ_OPS_COUNT` | Number of HFile block reads.
|
+| `RPC_SCAN_PROCESSING_TIME` | Time (ms) the RegionServer spent processing
the scan RPC. |
+| `RPC_SCAN_QUEUE_WAIT_TIME` | Time (ms) the scan RPC spent in the
RegionServer's call queue. |
+
+These are request-level metrics — they appear in the per-table map returned by
+`PhoenixRuntime.getRequestReadMetricInfo(rs)` alongside the existing entries:
+
+```java
+try (ResultSet rs = stmt.executeQuery(sql)) {
+ while (rs.next()) {
+ // ...
+ }
+ Map<String, Map<MetricType, Long>> readMetrics =
+ PhoenixRuntime.getRequestReadMetricInfo(rs);
+ long fsReadMs = readMetrics.get(tableName).get(MetricType.FS_READ_TIME);
+ long blocksRead =
readMetrics.get(tableName).get(MetricType.BLOCK_READ_OPS_COUNT);
+ // ...
+}
+```
+
+They piggyback on `phoenix.trace.read.metrics.enabled` (the existing
+request-level metrics switch, on by default) and require no additional
+configuration. Values originate from HBase 2.6.3+; on older HBase versions
Review Comment:
```suggestion
configuration. Values originate from HBase 2.6.4+; on older HBase versions
```
##########
app/pages/_docs/docs/_mdx/(multi-page)/features/metrics.mdx:
##########
@@ -117,3 +117,82 @@ service.submit(new Runnable() {
}
});
```
+
+## Scan latency metrics [#scan-latency-metrics]
+
+Phoenix 5.3.1 surfaces HBase's per-scan latency and IO metrics through the
+request-level metrics API, giving per-query visibility into where a scan
+actually spent its time
+([PHOENIX-7704](https://issues.apache.org/jira/browse/PHOENIX-7704)).
+
+| Metric | Description
|
+| ---------------------------- |
----------------------------------------------------------------------- |
+| `FS_READ_TIME` | Time (ms) spent in the underlying filesystem
(HDFS/S3) for HFile reads. |
+| `BYTES_READ_FROM_FS` | Bytes read from the filesystem — cold reads
that missed every cache. |
Review Comment:
```suggestion
| `BYTES_READ_FROM_FS` | Bytes read from the filesystem — cold reads
that missed HBase block cache. |
```
##########
app/pages/_docs/docs/_mdx/(multi-page)/features/metrics.mdx:
##########
@@ -117,3 +117,82 @@ service.submit(new Runnable() {
}
});
```
+
+## Scan latency metrics [#scan-latency-metrics]
+
+Phoenix 5.3.1 surfaces HBase's per-scan latency and IO metrics through the
+request-level metrics API, giving per-query visibility into where a scan
+actually spent its time
+([PHOENIX-7704](https://issues.apache.org/jira/browse/PHOENIX-7704)).
+
+| Metric | Description
|
+| ---------------------------- |
----------------------------------------------------------------------- |
+| `FS_READ_TIME` | Time (ms) spent in the underlying filesystem
(HDFS/S3) for HFile reads. |
+| `BYTES_READ_FROM_FS` | Bytes read from the filesystem — cold reads
that missed every cache. |
+| `BYTES_READ_FROM_MEMSTORE` | Bytes read from memstore — un-flushed cells.
|
+| `BYTES_READ_FROM_BLOCKCACHE` | Bytes served from the HBase block cache —
warm reads. |
+| `BLOCK_READ_OPS_COUNT` | Number of HFile block reads.
|
+| `RPC_SCAN_PROCESSING_TIME` | Time (ms) the RegionServer spent processing
the scan RPC. |
Review Comment:
```suggestion
| `RPC_SCAN_PROCESSING_TIME` | Time (ms) the RegionServer spent processing
the scan RPC in handler thread. |
```
##########
app/pages/_docs/docs/_mdx/(multi-page)/features/metrics.mdx:
##########
@@ -117,3 +117,82 @@ service.submit(new Runnable() {
}
});
```
+
+## Scan latency metrics [#scan-latency-metrics]
+
+Phoenix 5.3.1 surfaces HBase's per-scan latency and IO metrics through the
+request-level metrics API, giving per-query visibility into where a scan
+actually spent its time
+([PHOENIX-7704](https://issues.apache.org/jira/browse/PHOENIX-7704)).
+
+| Metric | Description
|
+| ---------------------------- |
----------------------------------------------------------------------- |
+| `FS_READ_TIME` | Time (ms) spent in the underlying filesystem
(HDFS/S3) for HFile reads. |
+| `BYTES_READ_FROM_FS` | Bytes read from the filesystem — cold reads
that missed every cache. |
+| `BYTES_READ_FROM_MEMSTORE` | Bytes read from memstore — un-flushed cells.
|
+| `BYTES_READ_FROM_BLOCKCACHE` | Bytes served from the HBase block cache —
warm reads. |
+| `BLOCK_READ_OPS_COUNT` | Number of HFile block reads.
|
+| `RPC_SCAN_PROCESSING_TIME` | Time (ms) the RegionServer spent processing
the scan RPC. |
+| `RPC_SCAN_QUEUE_WAIT_TIME` | Time (ms) the scan RPC spent in the
RegionServer's call queue. |
+
+These are request-level metrics — they appear in the per-table map returned by
+`PhoenixRuntime.getRequestReadMetricInfo(rs)` alongside the existing entries:
+
+```java
+try (ResultSet rs = stmt.executeQuery(sql)) {
+ while (rs.next()) {
+ // ...
+ }
+ Map<String, Map<MetricType, Long>> readMetrics =
+ PhoenixRuntime.getRequestReadMetricInfo(rs);
+ long fsReadMs = readMetrics.get(tableName).get(MetricType.FS_READ_TIME);
+ long blocksRead =
readMetrics.get(tableName).get(MetricType.BLOCK_READ_OPS_COUNT);
+ // ...
+}
+```
+
+They piggyback on `phoenix.trace.read.metrics.enabled` (the existing
+request-level metrics switch, on by default) and require no additional
+configuration. Values originate from HBase 2.6.3+; on older HBase versions
+they are silently zero.
+
+## Top-N slowest parallel scans [#top-n-slowest-scans]
+
+For diagnosing tail-latency on a single statement, Phoenix can retain the
Review Comment:
```suggestion
For diagnosing tail-latency on a single statement issuing multiple HBase
scans, Phoenix can retain the
```
##########
app/pages/_docs/docs/_mdx/(multi-page)/features/metrics.mdx:
##########
@@ -117,3 +117,82 @@ service.submit(new Runnable() {
}
});
```
+
+## Scan latency metrics [#scan-latency-metrics]
+
+Phoenix 5.3.1 surfaces HBase's per-scan latency and IO metrics through the
+request-level metrics API, giving per-query visibility into where a scan
+actually spent its time
+([PHOENIX-7704](https://issues.apache.org/jira/browse/PHOENIX-7704)).
+
+| Metric | Description
|
+| ---------------------------- |
----------------------------------------------------------------------- |
+| `FS_READ_TIME` | Time (ms) spent in the underlying filesystem
(HDFS/S3) for HFile reads. |
+| `BYTES_READ_FROM_FS` | Bytes read from the filesystem — cold reads
that missed every cache. |
+| `BYTES_READ_FROM_MEMSTORE` | Bytes read from memstore — un-flushed cells.
|
+| `BYTES_READ_FROM_BLOCKCACHE` | Bytes served from the HBase block cache —
warm reads. |
+| `BLOCK_READ_OPS_COUNT` | Number of HFile block reads.
|
Review Comment:
```suggestion
| `BLOCK_READ_OPS_COUNT` | Number of HFile blocks read from filesystem
(HDFS/S3). |
```
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