PromQL: Fix insufficient cardinality checking for filter ops#17668
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PromQL: Fix insufficient cardinality checking for filter ops#17668
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Generally, binary operations between two vectors fail if there is a many-to-one or one-to-many matching situation between series within a match group and no `group_left()` or `group_right()` modifier is present. For filter ops this is also generally the case, but there can be situations where multiple series on one side can match a single series on the other side, but only 0 or 1 of those multiple series remains after the filter operator has been applied. In this case, the PromQL engine does not produce a matching error, since it only tracks series matching for those series that survive the filtering. IMO this is incorrect behavior (which can also erratically make a query sometimes fail and sometimes succeed, depending on current sample values), and we should always produce an error if there is a match error prior to applying the filter op. This PR ensures that we do the cardinality / match tracking independently of the result of the filter operation. Signed-off-by: Julius Volz <julius.volz@gmail.com>
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Member
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This seems to be a breaking change? Some queries which previously worked will now fail. |
Member
Author
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@bboreham Yeah, this is one of these things that's a bit on the edge. It's changing behavior, but IMO behavior that was definitely broken and unintended and not what our documentation says about matching legality. I would hope to get away with it, also because it helps fix the match tracking code that is also needed for the fill modifiers 😬 I wonder if anyone might rely on the old broken behavior though. They would have to construct a query that does many-to-one matching, not have any |
Contributor
Arguably this is a bugfix - we change behavior of promql with bugfixes just about every release - some calculations return different values, some warnings change here and there; i dont think this is fundamentally different. |
Member
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Ah, I think I may not have understood the scope of the change.
I think you're saying that semantically the PromQL expression is one-to-one, but the data selected has many-to-many matches. I'm still a bit unclear in my head why this needs to be described differently between I'll link the discussion at #15114 about a comparable change to |
Member
Author
Exactly. And the query only returns without an error if the filter operator happens to remove all but one (or zero) of the "many" series.
Yes, there should be no difference in the legality of matching behavior for arithmetic operators and filter operators. But the previous (buggy) behavior was such that the filter operator was inadvertently applied (via
Ah right. That would also be good to fix at some point, but I can see how it might not be worth it at the moment if it would introduce too many complications. |
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##### [\`v3.9.0\`](https://github.com/prometheus/prometheus/releases/tag/v3.9.0) #### Note for users of Native Histograms In version 3.9, Native Histograms is no longer experimental, and the feature flag `native-histogram` has no effect. You must now turn on the config setting `scrape_native_histograms` to collect Native Histogram samples from exporters. #### Changelog - \[CHANGE] Native Histograms are no longer experimental! Make the `native-histogram` feature flag a no-op. Use `scrape_native_histograms` config option instead. [#17528](prometheus/prometheus#17528) - \[CHANGE] API: Add maximum limit of 10,000 sets of statistics to TSDB status endpoint. [#17647](prometheus/prometheus#17647) - \[FEATURE] API: Add /api/v1/features for clients to understand which features are supported. [#17427](prometheus/prometheus#17427) - \[FEATURE] Promtool: Add `start_timestamp` field for unit tests. [#17636](prometheus/prometheus#17636) - \[FEATURE] Promtool: Add `--format seriesjson` option to `tsdb dump` to output just series labels in JSON format. [#13409](prometheus/prometheus#13409) - \[FEATURE] Add `--storage.tsdb.delay-compact-file.path` flag for better interoperability with Thanos. [#17435](prometheus/prometheus#17435) - \[FEATURE] UI: Add an option on the query drop-down menu to duplicate that query panel. [#17714](prometheus/prometheus#17714) - \[ENHANCEMENT]: TSDB: add flag `--storage.tsdb.block-reload-interval` to configure TSDB Block Reload Interval. [#16728](prometheus/prometheus#16728) - \[ENHANCEMENT] UI: Add graph option to start the chart's Y axis at zero. [#17565](prometheus/prometheus#17565) - \[ENHANCEMENT] Scraping: Classic protobuf format no longer requires the unit in the metric name. [#16834](prometheus/prometheus#16834) - \[ENHANCEMENT] PromQL, Rules, SD, Scraping: Add native histograms to complement existing summaries. [#17374](prometheus/prometheus#17374) - \[ENHANCEMENT] Notifications: Add a histogram `prometheus_notifications_latency_histogram_seconds` to complement the existing summary. [#16637](prometheus/prometheus#16637) - \[ENHANCEMENT] Remote-write: Add custom scope support for AzureAD authentication. [#17483](prometheus/prometheus#17483) - \[ENHANCEMENT] SD: add a `config` label with job name for most `prometheus_sd_refresh` metrics. [#17138](prometheus/prometheus#17138) - \[ENHANCEMENT] TSDB: New histogram `prometheus_tsdb_sample_ooo_delta`, the distribution of out-of-order samples in seconds. Collected for all samples, accepted or not. [#17477](prometheus/prometheus#17477) - \[ENHANCEMENT] Remote-read: Validate histograms received via remote-read. [#17561](prometheus/prometheus#17561) - \[PERF] TSDB: Small optimizations to postings index. [#17439](prometheus/prometheus#17439) - \[PERF] Scraping: Speed up relabelling of series. [#17530](prometheus/prometheus#17530) - \[PERF] PromQL: Small optimisations in binary operators. [#17524](prometheus/prometheus#17524), [#17519](prometheus/prometheus#17519). - \[BUGFIX] UI: PromQL autocomplete now shows the correct type and HELP text for OpenMetrics counters whose samples end in `_total`. [#17682](prometheus/prometheus#17682) - \[BUGFIX] UI: Fixed codemirror-promql incorrectly showing label completion suggestions after the closing curly brace of a vector selector. [#17602](prometheus/prometheus#17602) - \[BUGFIX] UI: Query editor no longer suggests a duration unit if one is already present after a number. [#17605](prometheus/prometheus#17605) - \[BUGFIX] PromQL: Fix some "vector cannot contain metrics with the same labelset" errors when experimental delayed name removal is enabled. [#17678](prometheus/prometheus#17678) - \[BUGFIX] PromQL: Fix possible corruption of PromQL text if the query had an empty `ignoring()` and non-empty grouping. [#17643](prometheus/prometheus#17643) - \[BUGFIX] PromQL: Fix resets/changes to return empty results for anchored selectors when all samples are outside the range. [#17479](prometheus/prometheus#17479) - \[BUGFIX] PromQL: Check more consistently for many-to-one matching in filter binary operators. [#17668](prometheus/prometheus#17668) - \[BUGFIX] PromQL: Fix collision in unary negation with non-overlapping series. [#17708](prometheus/prometheus#17708) - \[BUGFIX] PromQL: Fix collision in label\_join and label\_replace with non-overlapping series. [#17703](prometheus/prometheus#17703) - \[BUGFIX] PromQL: Fix bug with inconsistent results for queries with OR expression when experimental delayed name removal is enabled. [#17161](prometheus/prometheus#17161) - \[BUGFIX] PromQL: Ensure that `rate`/`increase`/`delta` of histograms results in a gauge histogram. [#17608](prometheus/prometheus#17608) - \[BUGFIX] PromQL: Do not panic while iterating over invalid histograms. [#17559](prometheus/prometheus#17559) - \[BUGFIX] TSDB: Reject chunk files whose encoded chunk length overflows int. [#17533](prometheus/prometheus#17533) - \[BUGFIX] TSDB: Do not panic during resolution reduction of invalid histograms. [#17561](prometheus/prometheus#17561) - \[BUGFIX] Remote-write Receive: Avoid duplicate labels when experimental type-and-unit-label feature is enabled. [#17546](prometheus/prometheus#17546) - \[BUGFIX] OTLP Receiver: Only write metadata to disk when experimental metadata-wal-records feature is enabled. [#17472](prometheus/prometheus#17472)
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##### [\`v3.9.1\`](https://github.com/prometheus/prometheus/releases/tag/v3.9.1) - \[BUGFIX] Agent: fix crash shortly after startup from invalid type of object. [#17802](prometheus/prometheus#17802) - \[BUGFIX] Scraping: fix relabel keep/drop not working. [#17807](prometheus/prometheus#17807) --- ##### [\`v3.9.0\`](https://github.com/prometheus/prometheus/releases/tag/v3.9.0) #### Note for users of Native Histograms In version 3.9, Native Histograms is no longer experimental, and the feature flag `native-histogram` has no effect. You must now turn on the config setting `scrape_native_histograms` to collect Native Histogram samples from exporters. #### Changelog - \[CHANGE] Native Histograms are no longer experimental! Make the `native-histogram` feature flag a no-op. Use `scrape_native_histograms` config option instead. [#17528](prometheus/prometheus#17528) - \[CHANGE] API: Add maximum limit of 10,000 sets of statistics to TSDB status endpoint. [#17647](prometheus/prometheus#17647) - \[FEATURE] API: Add /api/v1/features for clients to understand which features are supported. [#17427](prometheus/prometheus#17427) - \[FEATURE] Promtool: Add `start_timestamp` field for unit tests. [#17636](prometheus/prometheus#17636) - \[FEATURE] Promtool: Add `--format seriesjson` option to `tsdb dump` to output just series labels in JSON format. [#13409](prometheus/prometheus#13409) - \[FEATURE] Add `--storage.tsdb.delay-compact-file.path` flag for better interoperability with Thanos. [#17435](prometheus/prometheus#17435) - \[FEATURE] UI: Add an option on the query drop-down menu to duplicate that query panel. [#17714](prometheus/prometheus#17714) - \[ENHANCEMENT]: TSDB: add flag `--storage.tsdb.block-reload-interval` to configure TSDB Block Reload Interval. [#16728](prometheus/prometheus#16728) - \[ENHANCEMENT] UI: Add graph option to start the chart's Y axis at zero. [#17565](prometheus/prometheus#17565) - \[ENHANCEMENT] Scraping: Classic protobuf format no longer requires the unit in the metric name. [#16834](prometheus/prometheus#16834) - \[ENHANCEMENT] PromQL, Rules, SD, Scraping: Add native histograms to complement existing summaries. [#17374](prometheus/prometheus#17374) - \[ENHANCEMENT] Notifications: Add a histogram `prometheus_notifications_latency_histogram_seconds` to complement the existing summary. [#16637](prometheus/prometheus#16637) - \[ENHANCEMENT] Remote-write: Add custom scope support for AzureAD authentication. [#17483](prometheus/prometheus#17483) - \[ENHANCEMENT] SD: add a `config` label with job name for most `prometheus_sd_refresh` metrics. [#17138](prometheus/prometheus#17138) - \[ENHANCEMENT] TSDB: New histogram `prometheus_tsdb_sample_ooo_delta`, the distribution of out-of-order samples in seconds. Collected for all samples, accepted or not. [#17477](prometheus/prometheus#17477) - \[ENHANCEMENT] Remote-read: Validate histograms received via remote-read. [#17561](prometheus/prometheus#17561) - \[PERF] TSDB: Small optimizations to postings index. [#17439](prometheus/prometheus#17439) - \[PERF] Scraping: Speed up relabelling of series. [#17530](prometheus/prometheus#17530) - \[PERF] PromQL: Small optimisations in binary operators. [#17524](prometheus/prometheus#17524), [#17519](prometheus/prometheus#17519). - \[BUGFIX] UI: PromQL autocomplete now shows the correct type and HELP text for OpenMetrics counters whose samples end in `_total`. [#17682](prometheus/prometheus#17682) - \[BUGFIX] UI: Fixed codemirror-promql incorrectly showing label completion suggestions after the closing curly brace of a vector selector. [#17602](prometheus/prometheus#17602) - \[BUGFIX] UI: Query editor no longer suggests a duration unit if one is already present after a number. [#17605](prometheus/prometheus#17605) - \[BUGFIX] PromQL: Fix some "vector cannot contain metrics with the same labelset" errors when experimental delayed name removal is enabled. [#17678](prometheus/prometheus#17678) - \[BUGFIX] PromQL: Fix possible corruption of PromQL text if the query had an empty `ignoring()` and non-empty grouping. [#17643](prometheus/prometheus#17643) - \[BUGFIX] PromQL: Fix resets/changes to return empty results for anchored selectors when all samples are outside the range. [#17479](prometheus/prometheus#17479) - \[BUGFIX] PromQL: Check more consistently for many-to-one matching in filter binary operators. [#17668](prometheus/prometheus#17668) - \[BUGFIX] PromQL: Fix collision in unary negation with non-overlapping series. [#17708](prometheus/prometheus#17708) - \[BUGFIX] PromQL: Fix collision in label\_join and label\_replace with non-overlapping series. [#17703](prometheus/prometheus#17703) - \[BUGFIX] PromQL: Fix bug with inconsistent results for queries with OR expression when experimental delayed name removal is enabled. [#17161](prometheus/prometheus#17161) - \[BUGFIX] PromQL: Ensure that `rate`/`increase`/`delta` of histograms results in a gauge histogram. [#17608](prometheus/prometheus#17608) - \[BUGFIX] PromQL: Do not panic while iterating over invalid histograms. [#17559](prometheus/prometheus#17559) - \[BUGFIX] TSDB: Reject chunk files whose encoded chunk length overflows int. [#17533](prometheus/prometheus#17533) - \[BUGFIX] TSDB: Do not panic during resolution reduction of invalid histograms. [#17561](prometheus/prometheus#17561) - \[BUGFIX] Remote-write Receive: Avoid duplicate labels when experimental type-and-unit-label feature is enabled. [#17546](prometheus/prometheus#17546) - \[BUGFIX] OTLP Receiver: Only write metadata to disk when experimental metadata-wal-records feature is enabled. [#17472](prometheus/prometheus#17472)
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##### [\`v3.9.1\`](https://github.com/prometheus/prometheus/releases/tag/v3.9.1) - \[BUGFIX] Agent: fix crash shortly after startup from invalid type of object. [#17802](prometheus/prometheus#17802) - \[BUGFIX] Scraping: fix relabel keep/drop not working. [#17807](prometheus/prometheus#17807) --- ##### [\`v3.9.0\`](https://github.com/prometheus/prometheus/releases/tag/v3.9.0) #### Note for users of Native Histograms In version 3.9, Native Histograms is no longer experimental, and the feature flag `native-histogram` has no effect. You must now turn on the config setting `scrape_native_histograms` to collect Native Histogram samples from exporters. #### Changelog - \[CHANGE] Native Histograms are no longer experimental! Make the `native-histogram` feature flag a no-op. Use `scrape_native_histograms` config option instead. [#17528](prometheus/prometheus#17528) - \[CHANGE] API: Add maximum limit of 10,000 sets of statistics to TSDB status endpoint. [#17647](prometheus/prometheus#17647) - \[FEATURE] API: Add /api/v1/features for clients to understand which features are supported. [#17427](prometheus/prometheus#17427) - \[FEATURE] Promtool: Add `start_timestamp` field for unit tests. [#17636](prometheus/prometheus#17636) - \[FEATURE] Promtool: Add `--format seriesjson` option to `tsdb dump` to output just series labels in JSON format. [#13409](prometheus/prometheus#13409) - \[FEATURE] Add `--storage.tsdb.delay-compact-file.path` flag for better interoperability with Thanos. [#17435](prometheus/prometheus#17435) - \[FEATURE] UI: Add an option on the query drop-down menu to duplicate that query panel. [#17714](prometheus/prometheus#17714) - \[ENHANCEMENT]: TSDB: add flag `--storage.tsdb.block-reload-interval` to configure TSDB Block Reload Interval. [#16728](prometheus/prometheus#16728) - \[ENHANCEMENT] UI: Add graph option to start the chart's Y axis at zero. [#17565](prometheus/prometheus#17565) - \[ENHANCEMENT] Scraping: Classic protobuf format no longer requires the unit in the metric name. [#16834](prometheus/prometheus#16834) - \[ENHANCEMENT] PromQL, Rules, SD, Scraping: Add native histograms to complement existing summaries. [#17374](prometheus/prometheus#17374) - \[ENHANCEMENT] Notifications: Add a histogram `prometheus_notifications_latency_histogram_seconds` to complement the existing summary. [#16637](prometheus/prometheus#16637) - \[ENHANCEMENT] Remote-write: Add custom scope support for AzureAD authentication. [#17483](prometheus/prometheus#17483) - \[ENHANCEMENT] SD: add a `config` label with job name for most `prometheus_sd_refresh` metrics. [#17138](prometheus/prometheus#17138) - \[ENHANCEMENT] TSDB: New histogram `prometheus_tsdb_sample_ooo_delta`, the distribution of out-of-order samples in seconds. Collected for all samples, accepted or not. [#17477](prometheus/prometheus#17477) - \[ENHANCEMENT] Remote-read: Validate histograms received via remote-read. [#17561](prometheus/prometheus#17561) - \[PERF] TSDB: Small optimizations to postings index. [#17439](prometheus/prometheus#17439) - \[PERF] Scraping: Speed up relabelling of series. [#17530](prometheus/prometheus#17530) - \[PERF] PromQL: Small optimisations in binary operators. [#17524](prometheus/prometheus#17524), [#17519](prometheus/prometheus#17519). - \[BUGFIX] UI: PromQL autocomplete now shows the correct type and HELP text for OpenMetrics counters whose samples end in `_total`. [#17682](prometheus/prometheus#17682) - \[BUGFIX] UI: Fixed codemirror-promql incorrectly showing label completion suggestions after the closing curly brace of a vector selector. [#17602](prometheus/prometheus#17602) - \[BUGFIX] UI: Query editor no longer suggests a duration unit if one is already present after a number. [#17605](prometheus/prometheus#17605) - \[BUGFIX] PromQL: Fix some "vector cannot contain metrics with the same labelset" errors when experimental delayed name removal is enabled. [#17678](prometheus/prometheus#17678) - \[BUGFIX] PromQL: Fix possible corruption of PromQL text if the query had an empty `ignoring()` and non-empty grouping. [#17643](prometheus/prometheus#17643) - \[BUGFIX] PromQL: Fix resets/changes to return empty results for anchored selectors when all samples are outside the range. [#17479](prometheus/prometheus#17479) - \[BUGFIX] PromQL: Check more consistently for many-to-one matching in filter binary operators. [#17668](prometheus/prometheus#17668) - \[BUGFIX] PromQL: Fix collision in unary negation with non-overlapping series. [#17708](prometheus/prometheus#17708) - \[BUGFIX] PromQL: Fix collision in label\_join and label\_replace with non-overlapping series. [#17703](prometheus/prometheus#17703) - \[BUGFIX] PromQL: Fix bug with inconsistent results for queries with OR expression when experimental delayed name removal is enabled. [#17161](prometheus/prometheus#17161) - \[BUGFIX] PromQL: Ensure that `rate`/`increase`/`delta` of histograms results in a gauge histogram. [#17608](prometheus/prometheus#17608) - \[BUGFIX] PromQL: Do not panic while iterating over invalid histograms. [#17559](prometheus/prometheus#17559) - \[BUGFIX] TSDB: Reject chunk files whose encoded chunk length overflows int. [#17533](prometheus/prometheus#17533) - \[BUGFIX] TSDB: Do not panic during resolution reduction of invalid histograms. [#17561](prometheus/prometheus#17561) - \[BUGFIX] Remote-write Receive: Avoid duplicate labels when experimental type-and-unit-label feature is enabled. [#17546](prometheus/prometheus#17546) - \[BUGFIX] OTLP Receiver: Only write metadata to disk when experimental metadata-wal-records feature is enabled. [#17472](prometheus/prometheus#17472)
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Generally, binary operations between two vectors fail if there is a many-to-one or one-to-many matching situation between series within a match group and no
group_left()orgroup_right()modifier is present. For filter ops this is also generally the case, but there can be situations where multiple series on one side can match a single series on the other side, but only 0 or 1 of those multiple series remains after the filter operator has been applied. In this case, the PromQL engine does not produce a matching error, since it only tracks series matching for those series that survive the filtering. IMO this is incorrect behavior (which can also erratically make a query sometimes fail and sometimes succeed, depending on current sample values), and we should always produce an error if there is a match error prior to applying the filter op.This PR ensures that we do the cardinality / match tracking independently of the result of the filter operation.
Does this PR introduce a user-facing change?