51 lines
1.9 KiB
Go
51 lines
1.9 KiB
Go
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package storage
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import (
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"github.com/influxdata/influxdb"
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"github.com/influxdata/influxql"
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)
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// StringIterator describes the behavior for enumerating a sequence of
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// string values.
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type StringIterator interface {
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// Next advances the StringIterator to the next value. It returns false
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// when there are no more values.
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Next() bool
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// Value returns the current value.
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Value() string
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}
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// TagKeys returns an iterator where the values are tag keys for the bucket
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// matching the predicate within the time range (start, end].
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func (e *Engine) TagKeys(orgID, bucketID influxdb.ID, start, end int64, predicate influxql.Expr) StringIterator {
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// This method would be invoked when the consumer wants to get the following schema information for an arbitrary
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// time range in a single bucket:
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//
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// * All tag keys;
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// * All tag keys filtered by an arbitrary predicate, e.g., tag keys for a measurement or tag keys appearing alongside another tag key pair.
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//
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return nullStringIterator
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}
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// TagValues returns an iterator which enumerates the values for the specific
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// tagKey in the given bucket matching the predicate within the
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// time range (start, end].
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func (e *Engine) TagValues(orgID, bucketID influxdb.ID, tagKey string, start, end int64, predicate influxql.Expr) StringIterator {
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// This method would be invoked when the consumer wants to get the following schema information for an arbitrary
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// time range in a single bucket:
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//
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// * All measurement names, i.e. tagKey == _measurement);
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// * All field names for a specific measurement using a predicate
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// * i.e. tagKey is "_field", predicate _measurement == "<measurement>"
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//
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return nullStringIterator
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}
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var nullStringIterator StringIterator = &emptyStringIterator{}
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type emptyStringIterator struct{}
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func (*emptyStringIterator) Next() bool { return false }
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func (*emptyStringIterator) Value() string { return "" }
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