risingwave_frontend/expr/
pure.rs

1// Copyright 2023 RisingWave Labs
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use std::borrow::Cow;
16
17use expr_node::Type;
18use risingwave_pb::expr::expr_node;
19
20use super::{ExprImpl, ExprVisitor};
21use crate::expr::FunctionCall;
22
23#[derive(Default)]
24pub(crate) struct ImpureAnalyzer {
25    impure: Option<Cow<'static, str>>,
26}
27
28impl ImpureAnalyzer {
29    /// Returns `true` if the expression is impure.
30    ///
31    /// Only call this method after visiting the expression.
32    pub fn is_impure(&self) -> bool {
33        self.impure.is_some()
34    }
35
36    /// Returns the description of the impure expression if it is impure, for error reporting.
37    /// `None` if the expression is pure.
38    ///
39    /// Only call this method after visiting the expression.
40    pub fn impure_expr_desc(&self) -> Option<&str> {
41        self.impure.as_deref()
42    }
43}
44
45impl ExprVisitor for ImpureAnalyzer {
46    fn visit_user_defined_function(&mut self, func_call: &super::UserDefinedFunction) {
47        let name = &func_call.catalog.name;
48        self.impure = Some(format!("user-defined function `{name}`").into());
49    }
50
51    fn visit_table_function(&mut self, func_call: &super::TableFunction) {
52        use crate::expr::table_function::TableFunctionType as Type;
53        let func_type = func_call.function_type;
54        match func_type {
55            Type::Unspecified => unreachable!(),
56
57            // deterministic
58            Type::GenerateSeries
59            | Type::Unnest
60            | Type::RegexpMatches
61            | Type::Range
62            | Type::GenerateSubscripts
63            | Type::PgExpandarray
64            | Type::JsonbArrayElements
65            | Type::JsonbArrayElementsText
66            | Type::JsonbEach
67            | Type::JsonbEachText
68            | Type::JsonbObjectKeys
69            | Type::JsonbPathQuery
70            | Type::JsonbPopulateRecordset
71            | Type::JsonbToRecordset => {
72                func_call.args.iter().for_each(|expr| self.visit_expr(expr));
73            }
74
75            // indeterministic
76            Type::FileScan
77            | Type::PostgresQuery
78            | Type::MysqlQuery
79            | Type::InternalBackfillProgress
80            | Type::InternalSourceBackfillProgress
81            | Type::InternalGetChannelDeltaStats
82            | Type::PgGetKeywords => {
83                self.impure = Some(func_type.as_str_name().into());
84            }
85            Type::UserDefined => {
86                let name = &func_call.user_defined.as_ref().unwrap().name;
87                self.impure = Some(format!("user-defined table function `{name}`").into());
88            }
89        }
90    }
91
92    fn visit_now(&mut self, _: &super::Now) {
93        self.impure = Some("NOW or PROCTIME".into());
94    }
95
96    fn visit_function_call(&mut self, func_call: &super::FunctionCall) {
97        let func_type = func_call.func_type();
98        match func_type {
99            Type::Unspecified => unreachable!(),
100            #[expect(deprecated)]
101            Type::Add
102            | Type::Subtract
103            | Type::Multiply
104            | Type::Divide
105            | Type::Modulus
106            | Type::Equal
107            | Type::NotEqual
108            | Type::LessThan
109            | Type::LessThanOrEqual
110            | Type::GreaterThan
111            | Type::GreaterThanOrEqual
112            | Type::And
113            | Type::Or
114            | Type::Not
115            | Type::In
116            | Type::Some
117            | Type::All
118            | Type::BitwiseAnd
119            | Type::BitwiseOr
120            | Type::BitwiseXor
121            | Type::BitwiseNot
122            | Type::BitwiseShiftLeft
123            | Type::BitwiseShiftRight
124            | Type::Extract
125            | Type::DatePart
126            | Type::TumbleStart
127            | Type::SecToTimestamptz
128            | Type::AtTimeZone
129            | Type::DateTrunc
130            | Type::DateBin
131            | Type::MakeDate
132            | Type::MakeTime
133            | Type::MakeTimestamp
134            | Type::CharToTimestamptz
135            | Type::CharToDate
136            | Type::CastWithTimeZone
137            | Type::AddWithTimeZone
138            | Type::SubtractWithTimeZone
139            | Type::Cast
140            | Type::Substr
141            | Type::Length
142            | Type::Like
143            | Type::ILike
144            | Type::SimilarToEscape
145            | Type::Upper
146            | Type::Lower
147            | Type::Trim
148            | Type::Replace
149            | Type::Position
150            | Type::Ltrim
151            | Type::Rtrim
152            | Type::Case
153            | Type::ConstantLookup
154            | Type::RoundDigit
155            | Type::Round
156            | Type::Ascii
157            | Type::Translate
158            | Type::Coalesce
159            | Type::ConcatWs
160            | Type::ConcatWsVariadic
161            | Type::Abs
162            | Type::SplitPart
163            | Type::Ceil
164            | Type::Floor
165            | Type::Trunc
166            | Type::ToChar
167            | Type::Md5
168            | Type::CharLength
169            | Type::Repeat
170            | Type::ConcatOp
171            | Type::ByteaConcatOp
172            | Type::Concat
173            | Type::ConcatVariadic
174            | Type::BoolOut
175            | Type::OctetLength
176            | Type::BitLength
177            | Type::Overlay
178            | Type::RegexpMatch
179            | Type::RegexpReplace
180            | Type::RegexpCount
181            | Type::RegexpSplitToArray
182            | Type::RegexpEq
183            | Type::Pow
184            | Type::Exp
185            | Type::Ln
186            | Type::Log10
187            | Type::Chr
188            | Type::StartsWith
189            | Type::Initcap
190            | Type::Lpad
191            | Type::Rpad
192            | Type::Reverse
193            | Type::Strpos
194            | Type::ToAscii
195            | Type::ToHex
196            | Type::QuoteIdent
197            | Type::Sin
198            | Type::Cos
199            | Type::Tan
200            | Type::Cot
201            | Type::Asin
202            | Type::Acos
203            | Type::Acosd
204            | Type::Atan
205            | Type::Atan2
206            | Type::Atand
207            | Type::Atan2d
208            | Type::Sqrt
209            | Type::Cbrt
210            | Type::Sign
211            | Type::Scale
212            | Type::MinScale
213            | Type::TrimScale
214            | Type::Gamma
215            | Type::Lgamma
216            | Type::Left
217            | Type::Right
218            | Type::Degrees
219            | Type::Radians
220            | Type::IsTrue
221            | Type::IsNotTrue
222            | Type::IsFalse
223            | Type::IsNotFalse
224            | Type::IsNull
225            | Type::IsNotNull
226            | Type::IsDistinctFrom
227            | Type::IsNotDistinctFrom
228            | Type::Neg
229            | Type::Field
230            | Type::Array
231            | Type::ArrayAccess
232            | Type::ArrayRangeAccess
233            | Type::Row
234            | Type::ArrayToString
235            | Type::ArrayCat
236            | Type::ArrayMax
237            | Type::ArraySum
238            | Type::ArraySort
239            | Type::ArrayAppend
240            | Type::ArrayReverse
241            | Type::ArrayPrepend
242            | Type::FormatType
243            | Type::ArrayDistinct
244            | Type::ArrayMin
245            | Type::ArrayDims
246            | Type::ArrayLength
247            | Type::Cardinality
248            | Type::TrimArray
249            | Type::ArrayRemove
250            | Type::ArrayReplace
251            | Type::ArrayPosition
252            | Type::ArrayContains
253            | Type::ArrayContained
254            | Type::ArrayFlatten
255            | Type::HexToInt256
256            | Type::JsonbConcat
257            | Type::JsonbAccess
258            | Type::JsonbAccessStr
259            | Type::JsonbExtractPath
260            | Type::JsonbExtractPathVariadic
261            | Type::JsonbExtractPathText
262            | Type::JsonbExtractPathTextVariadic
263            | Type::JsonbTypeof
264            | Type::JsonbArrayLength
265            | Type::JsonbObject
266            | Type::JsonbPretty
267            | Type::JsonbDeletePath
268            | Type::JsonbContains
269            | Type::JsonbContained
270            | Type::JsonbExists
271            | Type::JsonbExistsAny
272            | Type::JsonbExistsAll
273            | Type::JsonbStripNulls
274            | Type::JsonbBuildArray
275            | Type::JsonbBuildArrayVariadic
276            | Type::JsonbBuildObject
277            | Type::JsonbPopulateRecord
278            | Type::JsonbToArray
279            | Type::JsonbToRecord
280            | Type::JsonbBuildObjectVariadic
281            | Type::JsonbPathExists
282            | Type::JsonbPathMatch
283            | Type::JsonbPathQueryArray
284            | Type::JsonbPathQueryFirst
285            | Type::JsonbSet
286            | Type::JsonbPopulateMap
287            | Type::IsJson
288            | Type::ToJsonb
289            | Type::Sind
290            | Type::Cosd
291            | Type::Cotd
292            | Type::Asind
293            | Type::Sinh
294            | Type::Cosh
295            | Type::Coth
296            | Type::Tanh
297            | Type::Atanh
298            | Type::Asinh
299            | Type::Acosh
300            | Type::Decode
301            | Type::Encode
302            | Type::GetBit
303            | Type::GetByte
304            | Type::SetBit
305            | Type::SetByte
306            | Type::BitCount
307            | Type::Sha1
308            | Type::Sha224
309            | Type::Sha256
310            | Type::Sha384
311            | Type::Sha512
312            | Type::Crc32
313            | Type::Crc32c
314            | Type::Hmac
315            | Type::SecureCompare
316            | Type::Decrypt
317            | Type::Encrypt
318            | Type::Tand
319            | Type::ArrayPositions
320            | Type::StringToArray
321            | Type::Format
322            | Type::FormatVariadic
323            | Type::PgwireSend
324            | Type::PgwireRecv
325            | Type::ArrayTransform
326            | Type::Greatest
327            | Type::Least
328            | Type::ConvertFrom
329            | Type::ConvertTo
330            | Type::IcebergTransform
331            | Type::InetNtoa
332            | Type::InetAton
333            | Type::QuoteLiteral
334            | Type::QuoteNullable
335            | Type::MapFromEntries
336            | Type::MapAccess
337            | Type::MapKeys
338            | Type::MapValues
339            | Type::MapEntries
340            | Type::MapFromKeyValues
341            | Type::MapCat
342            | Type::MapContains
343            | Type::MapDelete
344            | Type::MapFilter
345            | Type::MapInsert
346            | Type::MapLength
347            | Type::L2Distance
348            | Type::CosineDistance
349            | Type::L1Distance
350            | Type::InnerProduct
351            | Type::VecConcat
352            | Type::L2Norm
353            | Type::L2Normalize
354            | Type::Subvector
355            // TODO: `rw_vnode` is more like STABLE instead of IMMUTABLE, because even its result is
356            // deterministic, it needs to read the total vnode count from the context, which means that
357            // it cannot be evaluated during constant folding. We have to treat it pure here so it can be used
358            // internally without materialization.
359            | Type::Vnode
360            | Type::VnodeUser
361            | Type::RwEpochToTs
362            | Type::CheckNotNull
363            | Type::CompositeCast =>
364            // expression output is deterministic(same result for the same input)
365            {
366                func_call
367                    .inputs()
368                    .iter()
369                    .for_each(|expr| self.visit_expr(expr));
370            }
371            // expression output is not deterministic
372            Type::TestFeature
373            | Type::License
374            | Type::Proctime
375            | Type::PgSleep
376            | Type::PgSleepFor
377            | Type::PgSleepUntil
378            | Type::CastRegclass
379            | Type::PgGetIndexdef
380            | Type::ColDescription
381            | Type::PgGetViewdef
382            | Type::PgGetUserbyid
383            | Type::PgIndexesSize
384            | Type::PgRelationSize
385            | Type::PgGetSerialSequence
386            | Type::PgIndexColumnHasProperty
387            | Type::HasTablePrivilege
388            | Type::HasAnyColumnPrivilege
389            | Type::HasSchemaPrivilege
390            | Type::MakeTimestamptz
391            | Type::PgIsInRecovery
392            | Type::RwRecoveryStatus
393            | Type::RwClusterId
394            | Type::RwFragmentVnodes
395            | Type::RwActorVnodes
396            | Type::PgTableIsVisible
397            | Type::HasFunctionPrivilege
398            | Type::OpenaiEmbedding
399            | Type::HasDatabasePrivilege
400            | Type::Random => self.impure = Some(func_type.as_str_name().into()),
401        }
402    }
403}
404
405pub fn is_pure(expr: &ExprImpl) -> bool {
406    !is_impure(expr)
407}
408
409pub fn is_impure(expr: &ExprImpl) -> bool {
410    let mut a = ImpureAnalyzer::default();
411    a.visit_expr(expr);
412    a.is_impure()
413}
414
415pub fn is_impure_func_call(func_call: &FunctionCall) -> bool {
416    let mut a = ImpureAnalyzer::default();
417    a.visit_function_call(func_call);
418    a.is_impure()
419}
420
421/// Returns the description of the impure expression if it is impure, for error reporting.
422/// `None` if the expression is pure.
423pub fn impure_expr_desc(expr: &ExprImpl) -> Option<String> {
424    let mut a = ImpureAnalyzer::default();
425    a.visit_expr(expr);
426    a.impure_expr_desc().map(|s| s.to_owned())
427}
428
429#[cfg(test)]
430mod tests {
431    use risingwave_common::types::DataType;
432    use risingwave_pb::expr::expr_node::Type;
433
434    use crate::expr::{ExprImpl, FunctionCall, InputRef, is_impure, is_pure};
435
436    fn expect_pure(expr: &ExprImpl) {
437        assert!(is_pure(expr));
438        assert!(!is_impure(expr));
439    }
440
441    fn expect_impure(expr: &ExprImpl) {
442        assert!(!is_pure(expr));
443        assert!(is_impure(expr));
444    }
445
446    #[test]
447    fn test_pure_funcs() {
448        let e: ExprImpl = FunctionCall::new(
449            Type::Add,
450            vec![
451                InputRef::new(0, DataType::Int16).into(),
452                InputRef::new(0, DataType::Int16).into(),
453            ],
454        )
455        .unwrap()
456        .into();
457        expect_pure(&e);
458
459        let e: ExprImpl = FunctionCall::new(
460            Type::GreaterThan,
461            vec![
462                InputRef::new(0, DataType::Timestamptz).into(),
463                FunctionCall::new(Type::Proctime, vec![]).unwrap().into(),
464            ],
465        )
466        .unwrap()
467        .into();
468        expect_impure(&e);
469    }
470}
risingwave_frontend/expr/pure.rs

risingwave_frontend/expr/
pure.rs
