func expandExprWithValues(expr influxql.Expr, keys []string, tagExprs []tagExpr, uniques [][]string, index int) []tagSetExpr {
// If we have no more keys left then execute the reduction and return.
if index == len(keys) {
// Create a map of tag key/values.
m := make(map[string]*string, len(keys))
for i, key := range keys {
if tagExprs[i].op == influxql.EQ {
m[key] = &tagExprs[i].values[0]
} else {
m[key] = nil
}
}
// TODO: Rewrite full expressions instead of VarRef replacement.
// Reduce using the current tag key/value set.
// Ignore it if reduces down to "false".
e := influxql.Reduce(expr, &tagValuer{tags: m})
if e, ok := e.(*influxql.BooleanLiteral); ok && e.Val == false {
return nil
}
return []tagSetExpr{{values: copyTagExprs(tagExprs), expr: e}}
}
// Otherwise expand for each possible equality value of the key.
var exprs []tagSetExpr
for _, v := range uniques[index] {
exprs = append(exprs, expandExprWithValues(expr, keys, append(tagExprs, tagExpr{keys[index], []string{v}, influxql.EQ}), uniques, index+1)...)
}
exprs = append(exprs, expandExprWithValues(expr, keys, append(tagExprs, tagExpr{keys[index], uniques[index], influxql.NEQ}), uniques, index+1)...)
return exprs
}
// Plan creates an execution plan for the given SelectStatement and returns an Executor.
func (q *QueryExecutor) PlanSelect(stmt *influxql.SelectStatement, chunkSize int) (Executor, error) {
shards := map[uint64]meta.ShardInfo{} // Shards requiring mappers.
// It is important to "stamp" this time so that everywhere we evaluate `now()` in the statement is EXACTLY the same `now`
now := time.Now().UTC()
// Replace instances of "now()" with the current time, and check the resultant times.
stmt.Condition = influxql.Reduce(stmt.Condition, &influxql.NowValuer{Now: now})
tmin, tmax := influxql.TimeRange(stmt.Condition)
if tmax.IsZero() {
tmax = now
}
if tmin.IsZero() {
tmin = time.Unix(0, 0)
}
for _, src := range stmt.Sources {
mm, ok := src.(*influxql.Measurement)
if !ok {
return nil, fmt.Errorf("invalid source type: %#v", src)
}
// Build the set of target shards. Using shard IDs as keys ensures each shard ID
// occurs only once.
shardGroups, err := q.MetaStore.ShardGroupsByTimeRange(mm.Database, mm.RetentionPolicy, tmin, tmax)
if err != nil {
return nil, err
}
for _, g := range shardGroups {
for _, sh := range g.Shards {
shards[sh.ID] = sh
}
}
}
// Build the Mappers, one per shard.
mappers := []Mapper{}
for _, sh := range shards {
m, err := q.ShardMapper.CreateMapper(sh, stmt, chunkSize)
if err != nil {
return nil, err
}
if m == nil {
// No data for this shard, skip it.
continue
}
mappers = append(mappers, m)
}
executor := NewSelectExecutor(stmt, mappers, chunkSize)
return executor, nil
}
// mergeSeriesFilters merges two sets of filter expressions and culls series IDs.
func mergeSeriesFilters(op influxql.Token, ids SeriesIDs, lfilters, rfilters map[uint64]influxql.Expr) (SeriesIDs, map[uint64]influxql.Expr) {
// Create a map to hold the final set of series filter expressions.
filters := make(map[uint64]influxql.Expr, 0)
// Resulting list of series IDs
var series SeriesIDs
// Combining logic:
// +==========+==========+==========+=======================+=======================+
// | operator | LHS | RHS | intermediate expr | reduced filter |
// +==========+==========+==========+=======================+=======================+
// | | <nil> | <r-expr> | true OR <r-expr> | true |
// | |----------+----------+-----------------------+-----------------------+
// | OR | <l-expr> | <nil> | <l-expr> OR true | true |
// | |----------+----------+-----------------------+-----------------------+
// | | <nil> | <nil> | true OR true | true |
// | |----------+----------+-----------------------+-----------------------+
// | | <l-expr> | <r-expr> | <l-expr> OR <r-expr> | <l-expr> OR <r-expr> |
// +----------+----------+----------+-----------------------+-----------------------+
// | | <nil> | <r-expr> | false AND <r-expr> | false* |
// | |----------+----------+-----------------------+-----------------------+
// | AND | <l-expr> | <nil> | <l-expr> AND false | false |
// | |----------+----------+-----------------------+-----------------------+
// | | <nil> | <nil> | false AND false | false |
// | |----------+----------+-----------------------+-----------------------+
// | | <l-expr> | <r-expr> | <l-expr> AND <r-expr> | <l-expr> AND <r-expr> |
// +----------+----------+----------+-----------------------+-----------------------+
// *literal false filters and series IDs should be excluded from the results
def := false
if op == influxql.OR {
def = true
}
for _, id := range ids {
// Get LHS and RHS filter expressions for this series ID.
lfilter, rfilter := lfilters[id], rfilters[id]
// Set default filters if either LHS or RHS expressions were nil.
if lfilter == nil {
lfilter = &influxql.BooleanLiteral{Val: def}
}
if rfilter == nil {
rfilter = &influxql.BooleanLiteral{Val: def}
}
// Create the intermediate filter expression for this series ID.
be := &influxql.BinaryExpr{
Op: op,
LHS: lfilter,
RHS: rfilter,
}
// Reduce the intermediate expression.
expr := influxql.Reduce(be, nil)
// If the expression reduced to false, exclude this series ID and filter.
if b, ok := expr.(*influxql.BooleanLiteral); ok && !b.Val {
continue
}
// Store the series ID and merged filter in the final results.
filters[id] = expr
series = append(series, id)
}
return series, filters
}
// Ensure an expression can be reduced.
func TestReduce(t *testing.T) {
now := mustParseTime("2000-01-01T00:00:00Z")
for i, tt := range []struct {
in string
out string
data Valuer
}{
// Number literals.
{in: `1 + 2`, out: `3.000`},
{in: `(foo*2) + ( (4/2) + (3 * 5) - 0.5 )`, out: `(foo * 2.000) + 16.500`},
{in: `foo(bar(2 + 3), 4)`, out: `foo(bar(5.000), 4.000)`},
{in: `4 / 0`, out: `0.000`},
{in: `4 = 4`, out: `true`},
{in: `4 <> 4`, out: `false`},
{in: `6 > 4`, out: `true`},
{in: `4 >= 4`, out: `true`},
{in: `4 < 6`, out: `true`},
{in: `4 <= 4`, out: `true`},
{in: `4 AND 5`, out: `4.000 AND 5.000`},
// Boolean literals.
{in: `true AND false`, out: `false`},
{in: `true OR false`, out: `true`},
{in: `true OR (foo = bar AND 1 > 2)`, out: `true`},
{in: `(foo = bar AND 1 > 2) OR true`, out: `true`},
{in: `false OR (foo = bar AND 1 > 2)`, out: `false`},
{in: `(foo = bar AND 1 > 2) OR false`, out: `false`},
{in: `true = false`, out: `false`},
{in: `true <> false`, out: `true`},
{in: `true + false`, out: `true + false`},
// Time literals.
{in: `now() + 2h`, out: `'2000-01-01T02:00:00Z'`, data: map[string]interface{}{"now()": now}},
{in: `now() / 2h`, out: `'2000-01-01T00:00:00Z' / 2h`, data: map[string]interface{}{"now()": now}},
{in: `4µ + now()`, out: `'2000-01-01T00:00:00.000004Z'`, data: map[string]interface{}{"now()": now}},
{in: `now() = now()`, out: `true`, data: map[string]interface{}{"now()": now}},
{in: `now() <> now()`, out: `false`, data: map[string]interface{}{"now()": now}},
{in: `now() < now() + 1h`, out: `true`, data: map[string]interface{}{"now()": now}},
{in: `now() <= now() + 1h`, out: `true`, data: map[string]interface{}{"now()": now}},
{in: `now() >= now() - 1h`, out: `true`, data: map[string]interface{}{"now()": now}},
{in: `now() > now() - 1h`, out: `true`, data: map[string]interface{}{"now()": now}},
{in: `now() - (now() - 60s)`, out: `1m`, data: map[string]interface{}{"now()": now}},
{in: `now() AND now()`, out: `'2000-01-01T00:00:00Z' AND '2000-01-01T00:00:00Z'`, data: map[string]interface{}{"now()": now}},
{in: `now()`, out: `now()`},
// Duration literals.
{in: `10m + 1h - 60s`, out: `69m`},
{in: `(10m / 2) * 5`, out: `25m`},
{in: `60s = 1m`, out: `true`},
{in: `60s <> 1m`, out: `false`},
{in: `60s < 1h`, out: `true`},
{in: `60s <= 1h`, out: `true`},
{in: `60s > 12s`, out: `true`},
{in: `60s >= 1m`, out: `true`},
{in: `60s AND 1m`, out: `1m AND 1m`},
{in: `60m / 0`, out: `0s`},
{in: `60m + 50`, out: `1h + 50.000`},
// String literals.
{in: `'foo' + 'bar'`, out: `'foobar'`},
// Variable references.
{in: `foo`, out: `'bar'`, data: map[string]interface{}{"foo": "bar"}},
{in: `foo = 'bar'`, out: `true`, data: map[string]interface{}{"foo": "bar"}},
{in: `foo = 'bar'`, out: `false`, data: map[string]interface{}{"foo": nil}},
{in: `foo <> 'bar'`, out: `false`, data: map[string]interface{}{"foo": nil}},
} {
// Fold expression.
expr := influxql.Reduce(MustParseExpr(tt.in), tt.data)
// Compare with expected output.
if out := expr.String(); tt.out != out {
t.Errorf("%d. %s: unexpected expr:\n\nexp=%s\n\ngot=%s\n\n", i, tt.in, tt.out, out)
continue
}
}
}