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a5445e09c2
VictoriaMetrics/app/vmselect
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Aliaksandr Valialkin a5445e09c2
Revert "app/vmselect: fix the way of counting raw samples in single query (#6464)" 
This reverts commit 5ecf439078.

Reason for revert: the previous logic was correct.

The purpose of `-search.maxSamplesPerQuery` command-line flag is to limit the amounts of CPU resources,
which could be taken by a single query - see https://docs.victoriametrics.com/#resource-usage-limits .
VictoriaMetrics processes samples in blocks during querying - it reads the block, then unpacks it,
then filters out samples outside the selected time range. This means that it _spends CPU time_
on reading and unpacking of _all the samples_ in every block on the requested time range,
even if only a single sample per each block matches the given time range.

The previous logic was effectively limiting CPU time a single query could take.
The new logic fails limiting CPU time a single query could take in some pathological cases
when only a small fraction of samples per each requested block fit the requested time range.
This allows performing multiplication DoS-attacks by querying very narrow time ranges over historical blocks,
which tend to be full. For example, if the `-search.maxSamplesPerQuery` equals to a billion,
and the query requests a single sample out of 8K samples per each block, this means that the query
may unpack a billion of such blocks without exceeding the limit, e.g. it may unpack and process 8K*1e9=8e12 samples.
This is not what the resource usage limits were created for originally - see https://docs.victoriametrics.com/#resource-usage-limits

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5851
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/6464
2024-06-25 02:55:43 +02:00
..
clusternative all: fix golangci-lint(revive) warnings after 0c0ed61ce7 2024-04-03 03:00:45 +03:00
deployment Rootless docker images by default (#358) 2020-03-27 21:18:32 +02:00
graphite app/vmselect/graphite: follow-up for 23ab865035 2024-04-03 03:07:15 +03:00
graphiteql app/vmselect: use strings.EqualFold instead of strings.ToLower where appropriate 2024-05-12 10:21:24 +02:00
multiarch all: run apk update && apk upgrade in base Alpine Docker image in order to get all the recent security fixes 2023-02-09 14:03:02 -08:00
netstorage Revert "app/vmselect: fix the way of counting raw samples in single query (#6464)" 2024-06-25 02:55:43 +02:00
prometheus chore: follow-up after c740a8042e 2024-06-03 11:53:37 +02:00
promql app/vmselect/promql: check for ranged vectors in aggr funcs if implicit conversions are disabled (#6450) 2024-06-17 14:25:43 +02:00
querystats app/vmselect: do not track queries with less than 1ms execution time at /api/v1/status/top_queries 2021-07-15 16:53:35 +03:00
searchutils docs: follow-up for 70eaa06f08 2024-03-25 15:33:11 +01:00
static/css app/vmselect: properly serve static css for /select/.../metric-relabel-debug page 2022-12-10 03:04:43 -08:00
vmui app/vmui: run make vmui-update after 65f414acee 2024-06-24 23:21:19 +02:00
main.go app/vmselect: update flag description (#6347) 2024-05-24 15:58:54 +02:00
Makefile Add build support for loong64 (#6222) 2024-05-10 14:32:05 +02:00
README.md app/vmselect: expose vmui at /vmselect/<accountID>/vmui/ instead of /vmselect/<accountID>/prometheus/vmui/ 2021-07-10 12:32:21 +03:00
vmui.go app/vmselect: add missing whitespace into the description for -vmui.defaultTimezone command-line flag 2024-02-01 14:49:48 +02:00

README.md

vmselect performs the following tasks:

  • Splits incoming selects to tasks for vmstorage nodes and issues these tasks to all the vmstorage nodes in the cluster.

  • Merges responses from all the vmstorage nodes and returns a single response.

The vmui directory contains static contents built from app/vmui package with make vmui-update command. The vmui page is available at http://<vmselect>:8481/select/<accountID>/vmui/.