RegExp filter work without filter

[srfrog]

Remove the restriction on regexp filter and lookups to depend on trigram index.

• If the trigram index is found, it is used.
• When used as filter, no index is required.
• When no index is found and called from root query, return error.

No breaking changes expected.

Closes #2565

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This change is 

[manishrjain]

Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on @srfrog)

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worker/task.go, line 908 at r1 (raw file):

	} else {
		out := &pb.Result{}
		err = qs.handleHasFunction(ctx, arg.q, out)

No need to grab all the uids for the predicate, if there already is a list of UIDs coming in funcArgs.q.UidList. You could just iterate over that, grab their values and run regexp over them.

We only need to call the has function, if we don't have a UidList coming into this, in case someone used it at the root. But, they themselves could run the has function first, and use a filter on regexp. That way, a list of uids is always passed to this func. So, we never need to generate a list of uids here.

[srfrog]

Reviewable status: 0 of 3 files reviewed, 1 unresolved discussion (waiting on @manishrjain)

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worker/task.go, line 908 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

No need to grab all the uids for the predicate, if there already is a list of UIDs coming in funcArgs.q.UidList. You could just iterate over that, grab their values and run regexp over them.

We only need to call the has function, if we don't have a UidList coming into this, in case someone used it at the root. But, they themselves could run the has function first, and use a filter on regexp. That way, a list of uids is always passed to this func. So, we never need to generate a list of uids here.

Done.

[manishrjain]

Reviewable status: 0 of 4 files reviewed, 1 unresolved discussion (waiting on @srfrog)

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worker/task.go, line 908 at r1 (raw file):

Previously, srfrog (Gus) wrote…

Done.

Still see the Has func being called. So, not sure what changed.

[srfrog]

Reviewable status: 0 of 4 files reviewed, 1 unresolved discussion (waiting on @manishrjain)

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worker/task.go, line 908 at r1 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

Still see the Has func being called. So, not sure what changed.

Removed, added an error when called from root without index

[manishrjain]

Reviewable status: 0 of 4 files reviewed, 2 unresolved discussions (waiting on @srfrog)

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worker/task.go, line 947 at r3 (raw file):

			vals, err = pl.AllUntaggedValues(arg.q.ReadTs)

		case lang != "":

This changes the ordering of the if statement. Can you bring it back to the original order?

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worker/task.go, line 964 at r3 (raw file):

			strVal, err := types.Convert(val, types.StringID)
			if err == nil && matchRegex(strVal, arg.srcFn.regex) {
				filtered.Uids = append(filtered.Uids, uid)

There was a break here. We only add the uid once.

Be careful with this code: It's easy to introduce hard to find bugs and cause regressions.

[srfrog]

Reviewable status: 0 of 4 files reviewed, 2 unresolved discussions (waiting on @manishrjain)

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worker/task.go, line 947 at r3 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

This changes the ordering of the if statement. Can you bring it back to the original order?

Done.

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worker/task.go, line 964 at r3 (raw file):

Previously, manishrjain (Manish R Jain) wrote…

There was a break here. We only add the uid once.

Be careful with this code: It's easy to introduce hard to find bugs and cause regressions.

Acked

[srfrog]

Reviewable status: 0 of 4 files reviewed, 2 unresolved discussions (waiting on @manishrjain)

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worker/task.go, line 964 at r3 (raw file):

Previously, srfrog (Gus) wrote…

Acked

Done.

[manishrjain]

Reviewed 3 of 4 files at r3, 1 of 1 files at r4.
Reviewable status: complete! all files reviewed, all discussions resolved