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| 1 | +// Copyright Quesma, licensed under the Elastic License 2.0. |
| 2 | +// SPDX-License-Identifier: Elastic-2.0 |
| 3 | +package quesma |
| 4 | + |
| 5 | +import ( |
| 6 | + "fmt" |
| 7 | + "quesma/logger" |
| 8 | + "quesma/model" |
| 9 | + "quesma/schema" |
| 10 | + "quesma/util" |
| 11 | +) |
| 12 | + |
| 13 | +type ( |
| 14 | + searchAfterStrategy interface { |
| 15 | + // validateAndParse validates the 'searchAfter', which is what came from the request's search_after field. |
| 16 | + validateAndParse(query *model.Query, indexSchema schema.Schema) (searchAfterParameterParsed []model.Expr, err error) |
| 17 | + transform(query *model.Query, searchAfterParameterParsed []model.Expr) (*model.Query, error) |
| 18 | + } |
| 19 | + searchAfterStrategyType int |
| 20 | +) |
| 21 | + |
| 22 | +func searchAfterStrategyFactory(strategy searchAfterStrategyType) searchAfterStrategy { |
| 23 | + switch strategy { |
| 24 | + case bulletproof: |
| 25 | + return searchAfterStrategyBulletproof{} |
| 26 | + case justDiscardTheParameter: |
| 27 | + return searchAfterStrategyJustDiscardTheParameter{} |
| 28 | + case basicAndFast: |
| 29 | + return searchAfterStrategyBasicAndFast{} |
| 30 | + default: |
| 31 | + logger.Error().Msgf("Unknown search_after strategy: %d. Using default (basicAndFast).", strategy) |
| 32 | + return searchAfterStrategyBasicAndFast{} |
| 33 | + } |
| 34 | +} |
| 35 | + |
| 36 | +const ( |
| 37 | + basicAndFast searchAfterStrategyType = iota // default until bulletproof is implemented |
| 38 | + bulletproof |
| 39 | + justDiscardTheParameter |
| 40 | + defaultSearchAfterStrategy = basicAndFast |
| 41 | +) |
| 42 | + |
| 43 | +func (s searchAfterStrategyType) String() string { |
| 44 | + return []string{"BasicAndFast", "Bulletproof", "JustDiscardTheParameter"}[s] |
| 45 | +} |
| 46 | + |
| 47 | +// --------------------------------------------------------------------------------- |
| 48 | +// | Bulletproof, but might be a bit slower for gigantic datasets | |
| 49 | +// --------------------------------------------------------------------------------- |
| 50 | + |
| 51 | +type searchAfterStrategyBulletproof struct{} // TODO, don't look! |
| 52 | + |
| 53 | +// validateAndParse validates the 'searchAfter', which is what came from the request's search_after field. |
| 54 | +func (s searchAfterStrategyBulletproof) validateAndParse(query *model.Query, indexSchema schema.Schema) (searchAfterParameterParsed []model.Expr, err error) { |
| 55 | + logger.Debug().Msgf("searchAfter: %v", query.SearchAfter) |
| 56 | + if query.SearchAfter == nil { |
| 57 | + return nil, nil |
| 58 | + } |
| 59 | + |
| 60 | + asArray, ok := query.SearchAfter.([]any) |
| 61 | + if !ok { |
| 62 | + return nil, fmt.Errorf("search_after must be an array, got: %v", query.SearchAfter) |
| 63 | + } |
| 64 | + |
| 65 | + if len(asArray) != len(query.SelectCommand.OrderBy) { |
| 66 | + return nil, fmt.Errorf("len(search_after) != len(sortFields), search_after: %v, sortFields: %v", asArray, query.SelectCommand.OrderBy) |
| 67 | + } |
| 68 | + |
| 69 | + return nil, nil |
| 70 | +} |
| 71 | + |
| 72 | +func (s searchAfterStrategyBulletproof) transform(query *model.Query, searchAfterParsed []model.Expr) (*model.Query, error) { |
| 73 | + return query, nil |
| 74 | +} |
| 75 | + |
| 76 | +// ------------------------------------------------------------------------------------------------------------------------------- |
| 77 | +// | JustDiscardTheParameter: probably only good for tests or when you don't need this functionality and want better performance | |
| 78 | +// ------------------------------------------------------------------------------------------------------------------------------- |
| 79 | + |
| 80 | +type searchAfterStrategyJustDiscardTheParameter struct{} |
| 81 | + |
| 82 | +// validateAndParse validates the 'searchAfter', which is what came from the request's search_after field. |
| 83 | +func (s searchAfterStrategyJustDiscardTheParameter) validateAndParse(*model.Query, schema.Schema) (searchAfterParameterParsed []model.Expr, err error) { |
| 84 | + return nil, nil |
| 85 | +} |
| 86 | + |
| 87 | +func (s searchAfterStrategyJustDiscardTheParameter) transform(query *model.Query, _ []model.Expr) (*model.Query, error) { |
| 88 | + return query, nil |
| 89 | +} |
| 90 | + |
| 91 | +// ---------------------------------------------------------------------------------- |
| 92 | +// | First, simple strategy: BasicAndFast (default until Bulletproof is implemented | |
| 93 | +// ---------------------------------------------------------------------------------- |
| 94 | + |
| 95 | +type searchAfterStrategyBasicAndFast struct{} |
| 96 | + |
| 97 | +// validateAndParse validates the 'searchAfter', which is what came from the request's search_after field. |
| 98 | +func (s searchAfterStrategyBasicAndFast) validateAndParse(query *model.Query, indexSchema schema.Schema) (searchAfterParsed []model.Expr, err error) { |
| 99 | + if query.SearchAfter == nil { |
| 100 | + return nil, nil |
| 101 | + } |
| 102 | + |
| 103 | + asArray, ok := query.SearchAfter.([]any) |
| 104 | + if !ok { |
| 105 | + return nil, fmt.Errorf("search_after must be an array, got: %v", query.SearchAfter) |
| 106 | + } |
| 107 | + if len(asArray) != len(query.SelectCommand.OrderBy) { |
| 108 | + return nil, fmt.Errorf("len(search_after) != len(sortFields), search_after: %v, sortFields: %v", asArray, query.SelectCommand.OrderBy) |
| 109 | + } |
| 110 | + |
| 111 | + sortFieldsNr := len(asArray) |
| 112 | + searchAfterParsed = make([]model.Expr, sortFieldsNr) |
| 113 | + for i, searchAfterValue := range asArray { |
| 114 | + column, ok := query.SelectCommand.OrderBy[i].Expr.(model.ColumnRef) |
| 115 | + if !ok { |
| 116 | + return nil, fmt.Errorf("for basicAndFast strategy, order by must be a column reference") |
| 117 | + } |
| 118 | + |
| 119 | + field, resolved := indexSchema.ResolveField(column.ColumnName) |
| 120 | + if !resolved { |
| 121 | + return nil, fmt.Errorf("could not resolve field: %v", model.AsString(query.SelectCommand.OrderBy[i].Expr)) |
| 122 | + } |
| 123 | + |
| 124 | + if field.Type.Name == "date" || field.Type.Name == "timestamp" { |
| 125 | + if number, isNumber := util.ExtractNumeric64Maybe(searchAfterValue); isNumber { |
| 126 | + if number >= 0 && util.IsFloat64AnInt64(number) { |
| 127 | + // this param will always be timestamp in milliseconds, as we create it like this while rendering hits |
| 128 | + searchAfterParsed[i] = model.NewFunction("fromUnixTimestamp64Milli", model.NewLiteral(int64(number))) |
| 129 | + } else { |
| 130 | + return nil, fmt.Errorf("for basicAndFast strategy, search_after must be a unix timestamp in milliseconds") |
| 131 | + } |
| 132 | + } else { |
| 133 | + return nil, fmt.Errorf("for basicAndFast strategy, search_after must be a number") |
| 134 | + } |
| 135 | + } else { |
| 136 | + searchAfterParsed[i] = model.NewLiteral(util.SingleQuoteIfString(searchAfterValue)) |
| 137 | + } |
| 138 | + } |
| 139 | + |
| 140 | + return searchAfterParsed, nil |
| 141 | +} |
| 142 | + |
| 143 | +func (s searchAfterStrategyBasicAndFast) transform(query *model.Query, searchAfterParsed []model.Expr) (*model.Query, error) { |
| 144 | + // If all order by's would be DESC, we would add to the where clause: |
| 145 | + // tuple(sortField1, sortField2, ...) > tuple(searchAfter1, searchAfter2, ...) |
| 146 | + // But because some fields might be ASC, we need to swap sortField_i with searchAfter_i |
| 147 | + sortFieldsNr := len(searchAfterParsed) |
| 148 | + lhs := model.NewTupleExpr(make([]model.Expr, sortFieldsNr)...) |
| 149 | + rhs := model.NewTupleExpr(make([]model.Expr, sortFieldsNr)...) |
| 150 | + for i, searchAfterValue := range searchAfterParsed { |
| 151 | + lhs.Exprs[i] = searchAfterValue |
| 152 | + rhs.Exprs[i] = query.SelectCommand.OrderBy[i].Expr |
| 153 | + if query.SelectCommand.OrderBy[i].Direction == model.AscOrder { |
| 154 | + lhs.Exprs[i], rhs.Exprs[i] = rhs.Exprs[i], lhs.Exprs[i] // swap |
| 155 | + } |
| 156 | + } |
| 157 | + |
| 158 | + newWhereClause := model.NewInfixExpr(lhs, ">", rhs) |
| 159 | + query.SelectCommand.WhereClause = model.And([]model.Expr{query.SelectCommand.WhereClause, newWhereClause}) |
| 160 | + return query, nil |
| 161 | +} |
| 162 | + |
| 163 | +func (s *SchemaCheckPass) applySearchAfterParameter(indexSchema schema.Schema, query *model.Query) (*model.Query, error) { |
| 164 | + searchAfterParsed, err := s.searchAfterStrategy.validateAndParse(query, indexSchema) |
| 165 | + if err != nil { |
| 166 | + return nil, err |
| 167 | + } |
| 168 | + if searchAfterParsed == nil { |
| 169 | + return query, nil |
| 170 | + } |
| 171 | + |
| 172 | + return s.searchAfterStrategy.transform(query, searchAfterParsed) |
| 173 | +} |
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