Prior to this change, all alert instance writes and deletes happened
individually, in their own database transaction. This change batches up
writes or deletes for a given rule's evaluation loop into a single
transaction before applying it.
These new transactions are off by default, guarded by the feature toggle "alertingBigTransactions"
Before:
```
goos: darwin
goarch: arm64
pkg: github.com/grafana/grafana/pkg/services/ngalert/store
BenchmarkAlertInstanceOperations-8 398 2991381 ns/op 1133537 B/op 27703 allocs/op
--- BENCH: BenchmarkAlertInstanceOperations-8
util.go:127: alert definition: {orgID: 1, UID: FovKXiRVzm} with title: "an alert definition FTvFXmRVkz" interval: 60 created
util.go:127: alert definition: {orgID: 1, UID: foDFXmRVkm} with title: "an alert definition fovFXmRVkz" interval: 60 created
util.go:127: alert definition: {orgID: 1, UID: VQvFuigVkm} with title: "an alert definition VwDKXmR4kz" interval: 60 created
PASS
ok github.com/grafana/grafana/pkg/services/ngalert/store 1.619s
```
After:
```
goos: darwin
goarch: arm64
pkg: github.com/grafana/grafana/pkg/services/ngalert/store
BenchmarkAlertInstanceOperations-8 1440 816484 ns/op 352297 B/op 6529 allocs/op
--- BENCH: BenchmarkAlertInstanceOperations-8
util.go:127: alert definition: {orgID: 1, UID: 302r_igVzm} with title: "an alert definition q0h9lmR4zz" interval: 60 created
util.go:127: alert definition: {orgID: 1, UID: 71hrlmR4km} with title: "an alert definition nJ29_mR4zz" interval: 60 created
util.go:127: alert definition: {orgID: 1, UID: Cahr_mR4zm} with title: "an alert definition ja2rlmg4zz" interval: 60 created
PASS
ok github.com/grafana/grafana/pkg/services/ngalert/store 1.383s
```
So we cut time by about 75% and memory allocations by about 60% when
storing and deleting 100 instances.
* Move fakeRuleStore to tests/fakes package
* Break stub dependencies on store
* Update existing tests to point to new location
* Remove unused stub of TimeNow
* Rename fake to take advantage of package name
Prior to this change, all alert instance writes and deletes happened
individually, in their own database transaction. This change batches up
writes or deletes for a given rule's evaluation loop into a single
transaction before applying it.
Before:
```
goos: darwin
goarch: arm64
pkg: github.com/grafana/grafana/pkg/services/ngalert/store
BenchmarkAlertInstanceOperations-8 398 2991381 ns/op 1133537 B/op 27703 allocs/op
--- BENCH: BenchmarkAlertInstanceOperations-8
util.go:127: alert definition: {orgID: 1, UID: FovKXiRVzm} with title: "an alert definition FTvFXmRVkz" interval: 60 created
util.go:127: alert definition: {orgID: 1, UID: foDFXmRVkm} with title: "an alert definition fovFXmRVkz" interval: 60 created
util.go:127: alert definition: {orgID: 1, UID: VQvFuigVkm} with title: "an alert definition VwDKXmR4kz" interval: 60 created
PASS
ok github.com/grafana/grafana/pkg/services/ngalert/store 1.619s
```
After:
```
goos: darwin
goarch: arm64
pkg: github.com/grafana/grafana/pkg/services/ngalert/store
BenchmarkAlertInstanceOperations-8 1440 816484 ns/op 352297 B/op 6529 allocs/op
--- BENCH: BenchmarkAlertInstanceOperations-8
util.go:127: alert definition: {orgID: 1, UID: 302r_igVzm} with title: "an alert definition q0h9lmR4zz" interval: 60 created
util.go:127: alert definition: {orgID: 1, UID: 71hrlmR4km} with title: "an alert definition nJ29_mR4zz" interval: 60 created
util.go:127: alert definition: {orgID: 1, UID: Cahr_mR4zm} with title: "an alert definition ja2rlmg4zz" interval: 60 created
PASS
ok github.com/grafana/grafana/pkg/services/ngalert/store 1.383s
```
So we cut time by about 75% and memory allocations by about 60% when
storing and deleting 100 instances.
This change also updates some of our tests so that they run successfully against postgreSQL - we were using random Int64s, but postgres integers, which our tables use, max out at 2^31-1
