lib/promscrape: return error if sample_limit or series_limit options are set when stream parsing mode is enabled

app/vmagent/README.md

@@ -329,7 +329,7 @@ scrape_configs:
     'match[]': ['{__name__!=""}']
 ```
 
-Note that `sample_limit` option doesn't prevent from data push to remote storage if stream parsing is enabled because the parsed data is pushed to remote storage as soon as it is parsed.
+Note that `sample_limit` and `series_limit` options cannot be used in stream parsing mode because the parsed data is pushed to remote storage as soon as it is parsed.
 
 
 ## Scraping big number of targets

docs/CHANGELOG.md

@@ -9,6 +9,7 @@ sort: 15
 * FEATURE: vmagent: expose `-promscrape.config` contents at `/config` page as Prometheus does. See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1695).
 * FEATURE: vmagent: add `show original labels` button per each scrape target displayed at `http://vmagent;8429/targets` page. This should improve debuggability for service discovery and relabeling issues similar to [this one](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1664). See [this feature request](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1698).
 * FEATURE: vmagent: shard targets among cluster nodes after the relabeling is applied. This should guarantee that targets with the same set of labels go to the same `vmagent` node in the cluster. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1687).
+* FEATURE: vmagent: return error if `sample_limit` or `series_limit` options are set when [stream parsing mode](https://docs.victoriametrics.com/vmagent.html#stream-parsing-mode) is enabled, since these limits cannot be applied in stream parsing mode.
 * FEATURE: add trigonometric functions, which are going to be added in [Prometheus 2.31](https://github.com/prometheus/prometheus/pull/9239): [acosh](https://docs.victoriametrics.com/MetricsQL.html#acosh), [asinh](https://docs.victoriametrics.com/MetricsQL.html#asinh), [atan](https://docs.victoriametrics.com/MetricsQL.html#atan), [atanh](https://docs.victoriametrics.com/MetricsQL.html#atanh), [cosh](https://docs.victoriametrics.com/MetricsQL.html#cosh), [deg](https://docs.victoriametrics.com/MetricsQL.html#deg), [rad](https://docs.victoriametrics.com/MetricsQL.html#rad), [sinh](https://docs.victoriametrics.com/MetricsQL.html#sinh), [tan](https://docs.victoriametrics.com/MetricsQL.html#tan), [tanh](https://docs.victoriametrics.com/MetricsQL.html#tanh). Also add `atan2` binary operator. See [this pull request](https://github.com/prometheus/prometheus/pull/9248).
 * FEATURE: consistently return the same set of time series from [limitk](https://docs.victoriametrics.com/MetricsQL.html#limitk) function. This improves the usability of periodically refreshed graphs.
 

docs/vmagent.md

@@ -333,7 +333,7 @@ scrape_configs:
     'match[]': ['{__name__!=""}']
 ```
 
-Note that `sample_limit` option doesn't prevent from data push to remote storage if stream parsing is enabled because the parsed data is pushed to remote storage as soon as it is parsed.
+Note that `sample_limit` and `series_limit` options cannot be used in stream parsing mode because the parsed data is pushed to remote storage as soon as it is parsed.
 
 
 ## Scraping big number of targets

lib/promscrape/config.go

@@ -753,6 +753,12 @@ func getScrapeWorkConfig(sc *ScrapeConfig, baseDir string, globalCfg *GlobalConf
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse `metric_relabel_configs` for `job_name` %q: %w", jobName, err)
 	}
+	if (*streamParse || sc.StreamParse) && sc.SampleLimit > 0 {
+		return nil, fmt.Errorf("cannot use stream parsing mode when `sample_limit` is set for `job_name` %q", jobName)
+	}
+	if (*streamParse || sc.StreamParse) && sc.SeriesLimit > 0 {
+		return nil, fmt.Errorf("cannot use stream parsing mode when `series_limit` is set for `job_name` %q", jobName)
+	}
 	swc := &scrapeWorkConfig{
 		scrapeInterval:       scrapeInterval,
 		scrapeTimeout:        scrapeTimeout,