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| 1 | +package io.substrait.isthmus; |
| 2 | + |
| 3 | +import com.google.common.collect.ImmutableSet; |
| 4 | +import io.substrait.isthmus.SqlConverterBase.DefinedTable; |
| 5 | +import io.substrait.relation.NamedScan; |
| 6 | +import io.substrait.relation.Rel; |
| 7 | +import io.substrait.relation.RelCopyOnWriteVisitor; |
| 8 | +import io.substrait.type.NamedStruct; |
| 9 | +import java.util.ArrayList; |
| 10 | +import java.util.HashMap; |
| 11 | +import java.util.List; |
| 12 | +import java.util.Map; |
| 13 | +import java.util.Optional; |
| 14 | +import java.util.Set; |
| 15 | +import java.util.function.Function; |
| 16 | +import java.util.stream.Collectors; |
| 17 | +import org.apache.calcite.jdbc.CalciteSchema; |
| 18 | +import org.apache.calcite.rel.type.RelDataTypeFactory; |
| 19 | +import org.apache.calcite.schema.Schema; |
| 20 | +import org.apache.calcite.schema.Table; |
| 21 | +import org.apache.calcite.schema.impl.AbstractSchema; |
| 22 | +import org.apache.calcite.schema.lookup.LikePattern; |
| 23 | +import org.apache.calcite.schema.lookup.Lookup; |
| 24 | +import org.apache.calcite.schema.lookup.Named; |
| 25 | +import org.checkerframework.checker.nullness.qual.Nullable; |
| 26 | + |
| 27 | +/** |
| 28 | + * A subclass of the Calcite Schema for creation from a Substrait relation |
| 29 | + * |
| 30 | + * <p>Implementation note: |
| 31 | + * |
| 32 | + * <p>The external Isthmus API can take a function that will return the table schema when needed, |
| 33 | + * rather than it being available up front. |
| 34 | + * |
| 35 | + * <p>This was implemented by a special subclass of the Calcite simple schema. Since this was |
| 36 | + * changed in Calcite 1.39.0; it failed to work; the protected methods it extended from changed. |
| 37 | + * |
| 38 | + * <p>The change, ironically, was to support a lazy approach to looking up Calcite schemas. Good - |
| 39 | + * *but* the external function in Isthmus is assuming it's going to get called with a fully |
| 40 | + * namespaced table name. Which Calcite though sees as being subschemas. |
| 41 | + * |
| 42 | + * <p>This results in some 'complex' code below to try and map the lazy way Calcite now works and |
| 43 | + * maintain the existing Isthmus API |
| 44 | + * |
| 45 | + * <p>If that Ishtmus API hadn't existed, this code would be a lot simpler! Maybe a case for future |
| 46 | + * deprecation. |
| 47 | + */ |
| 48 | +public class SubstraitCalciteSchema extends AbstractSchema { |
| 49 | + |
| 50 | + private Map<String, Table> tables; |
| 51 | + private Function<List<String>, NamedStruct> tableLookup; |
| 52 | + |
| 53 | + private RelDataTypeFactory typeFactory; |
| 54 | + private TypeConverter typeConverter; |
| 55 | + |
| 56 | + /** |
| 57 | + * Maintain a track of the 'prefix' of this schema... i.e. allows recreation of the fully |
| 58 | + * qualified name of this subschema |
| 59 | + */ |
| 60 | + private List<String> prefix = new ArrayList<>(); |
| 61 | + |
| 62 | + protected SubstraitCalciteSchema(Map<String, Table> tables) { |
| 63 | + this.tables = tables; |
| 64 | + } |
| 65 | + |
| 66 | + protected SubstraitCalciteSchema( |
| 67 | + Function<List<String>, NamedStruct> tableLookup, |
| 68 | + RelDataTypeFactory typeFactory, |
| 69 | + TypeConverter typeConverter) { |
| 70 | + this.tableLookup = tableLookup; |
| 71 | + this.typeFactory = typeFactory; |
| 72 | + this.typeConverter = typeConverter; |
| 73 | + } |
| 74 | + |
| 75 | + @Override |
| 76 | + protected Map<String, Table> getTableMap() { |
| 77 | + return tables; |
| 78 | + } |
| 79 | + |
| 80 | + @Override |
| 81 | + public Lookup<? extends Schema> subSchemas() { |
| 82 | + var defaultLookup = super.subSchemas(); |
| 83 | + |
| 84 | + // Note ono the lookups, calcite prefers calling getIgnoreCase() initially |
| 85 | + |
| 86 | + return new Lookup<>() { |
| 87 | + |
| 88 | + @Override |
| 89 | + public @Nullable Schema get(String name) { |
| 90 | + |
| 91 | + // before we create the next subschema, we need to check if this |
| 92 | + // is actually the final value. i.e. we need to call the lookup |
| 93 | + // if it is the final table, we then return null here. |
| 94 | + // Calcite sees that, knows there are no more schemas and instead |
| 95 | + // calls the tables() look up to get a table name. |
| 96 | + var lookupNameList = new ArrayList<String>(prefix); |
| 97 | + lookupNameList.add(name); |
| 98 | + |
| 99 | + NamedStruct table = tableLookup.apply(lookupNameList); |
| 100 | + if (table != null) { |
| 101 | + return null; |
| 102 | + } |
| 103 | + |
| 104 | + var scs = new SubstraitCalciteSchema(tableLookup, typeFactory, typeConverter); |
| 105 | + scs.prefix = lookupNameList; |
| 106 | + return scs; |
| 107 | + } |
| 108 | + |
| 109 | + @Override |
| 110 | + public @Nullable Named<Schema> getIgnoreCase(String name) { |
| 111 | + |
| 112 | + // before we create the next subschema, we need to check if this |
| 113 | + // is actually the final value. i.e. we need to call the lookup |
| 114 | + // if it is the final table, we then return null here/ |
| 115 | + // Calcite sees that there's no more schemas and instead |
| 116 | + // calls the tables() lazy look up to get a table name. |
| 117 | + var lookupNameList = new ArrayList<String>(prefix); |
| 118 | + lookupNameList.add(name); |
| 119 | + |
| 120 | + NamedStruct table = tableLookup.apply(lookupNameList); |
| 121 | + if (table != null) { |
| 122 | + return null; |
| 123 | + } |
| 124 | + |
| 125 | + var scs = new SubstraitCalciteSchema(tableLookup, typeFactory, typeConverter); |
| 126 | + scs.prefix = lookupNameList; |
| 127 | + return new Named<>(name, scs); |
| 128 | + } |
| 129 | + |
| 130 | + @Override |
| 131 | + public Set<String> getNames(LikePattern pattern) { |
| 132 | + return defaultLookup.getNames(pattern); |
| 133 | + } |
| 134 | + }; |
| 135 | + } |
| 136 | + |
| 137 | + @Override |
| 138 | + public Lookup<Table> tables() { |
| 139 | + if (this.tables != null) { |
| 140 | + // If we do have the list of tables already specified, delegate to the super class to return |
| 141 | + // those |
| 142 | + return super.tables(); |
| 143 | + } |
| 144 | + |
| 145 | + return new Lookup<Table>() { |
| 146 | + |
| 147 | + @Override |
| 148 | + public @Nullable Table get(String name) { |
| 149 | + List<String> p = new ArrayList<>(prefix); |
| 150 | + p.add(name); |
| 151 | + |
| 152 | + NamedStruct table = tableLookup.apply(p); |
| 153 | + if (table == null) { |
| 154 | + return null; |
| 155 | + } |
| 156 | + |
| 157 | + return new DefinedTable( |
| 158 | + name, typeFactory, typeConverter.toCalcite(typeFactory, table.struct(), table.names())); |
| 159 | + } |
| 160 | + |
| 161 | + @Override |
| 162 | + public @Nullable Named<Table> getIgnoreCase(String name) { |
| 163 | + /** Delegate to the noremal lookup */ |
| 164 | + return new Named<Table>(name, get(name)); |
| 165 | + } |
| 166 | + |
| 167 | + @Override |
| 168 | + public Set<String> getNames(LikePattern pattern) { |
| 169 | + return ImmutableSet.of(); |
| 170 | + } |
| 171 | + }; |
| 172 | + } |
| 173 | + |
| 174 | + /** |
| 175 | + * Turn this into a root Calciteschema Choice of settings is based on current isthmus behaviour |
| 176 | + */ |
| 177 | + public CalciteSchema getRootSchema() { |
| 178 | + return CalciteSchema.createRootSchema(false, false, "", this); |
| 179 | + } |
| 180 | + |
| 181 | + public static Builder builder() { |
| 182 | + return new Builder(); |
| 183 | + } |
| 184 | + |
| 185 | + /** |
| 186 | + * Builder class to assist with creating the CalciteSchema |
| 187 | + * |
| 188 | + * <p>Can be created from a Rel or a Lookup function |
| 189 | + */ |
| 190 | + public static class Builder { |
| 191 | + |
| 192 | + private Rel rel; |
| 193 | + private RelDataTypeFactory typeFactory; |
| 194 | + private TypeConverter typeConverter; |
| 195 | + private Function<List<String>, NamedStruct> tableLookup; |
| 196 | + |
| 197 | + public Builder withTableLookup(Function<List<String>, NamedStruct> tableLookup) { |
| 198 | + this.tableLookup = tableLookup; |
| 199 | + return this; |
| 200 | + } |
| 201 | + |
| 202 | + public Builder withTypeFactory(RelDataTypeFactory typeFactory) { |
| 203 | + this.typeFactory = typeFactory; |
| 204 | + return this; |
| 205 | + } |
| 206 | + |
| 207 | + public Builder withTypeConverter(TypeConverter typeConverter) { |
| 208 | + this.typeConverter = typeConverter; |
| 209 | + return this; |
| 210 | + } |
| 211 | + |
| 212 | + public Builder withSubstraitRel(Rel rel) { |
| 213 | + this.rel = rel; |
| 214 | + return this; |
| 215 | + } |
| 216 | + |
| 217 | + public SubstraitCalciteSchema build() { |
| 218 | + if (typeConverter == null) { |
| 219 | + throw new IllegalArgumentException("TypeConverter must be specified"); |
| 220 | + } |
| 221 | + |
| 222 | + if (typeFactory == null) { |
| 223 | + throw new IllegalArgumentException("TypeFactory must be specified"); |
| 224 | + } |
| 225 | + |
| 226 | + if (rel != null && tableLookup != null) { |
| 227 | + throw new IllegalArgumentException("Specify either 'rel' or 'tableLookup' "); |
| 228 | + } |
| 229 | + |
| 230 | + if (rel != null) { |
| 231 | + // If there are any named structs within the relation, gather these and convert |
| 232 | + // them to a map of tables |
| 233 | + // index by name; note that the name of the table is 'un-namespaced' here. |
| 234 | + // This was the existing logic so it has not been altered. |
| 235 | + Map<List<String>, NamedStruct> tableMap = NamedStructGatherer.gatherTables(rel); |
| 236 | + |
| 237 | + Map<String, Table> tables = |
| 238 | + tableMap.entrySet().stream() |
| 239 | + .map( |
| 240 | + entry -> { |
| 241 | + var id = entry.getKey(); |
| 242 | + var name = id.get(id.size() - 1); |
| 243 | + var table = entry.getValue(); |
| 244 | + var value = |
| 245 | + new SqlConverterBase.DefinedTable( |
| 246 | + name, |
| 247 | + typeFactory, |
| 248 | + typeConverter.toCalcite(typeFactory, table.struct(), table.names())); |
| 249 | + return Map.entry(name, value); |
| 250 | + }) |
| 251 | + .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue)); |
| 252 | + |
| 253 | + return new SubstraitCalciteSchema(tables); |
| 254 | + } else { |
| 255 | + return new SubstraitCalciteSchema(tableLookup, typeFactory, typeConverter); |
| 256 | + } |
| 257 | + } |
| 258 | + } |
| 259 | + |
| 260 | + private static final class NamedStructGatherer extends RelCopyOnWriteVisitor<RuntimeException> { |
| 261 | + Map<List<String>, NamedStruct> tableMap; |
| 262 | + |
| 263 | + private NamedStructGatherer() { |
| 264 | + super(); |
| 265 | + this.tableMap = new HashMap<>(); |
| 266 | + } |
| 267 | + |
| 268 | + public static Map<List<String>, NamedStruct> gatherTables(Rel rel) { |
| 269 | + var visitor = new NamedStructGatherer(); |
| 270 | + rel.accept(visitor); |
| 271 | + return visitor.tableMap; |
| 272 | + } |
| 273 | + |
| 274 | + @Override |
| 275 | + public Optional<Rel> visit(NamedScan namedScan) { |
| 276 | + Optional<Rel> result = super.visit(namedScan); |
| 277 | + |
| 278 | + List<String> tableName = namedScan.getNames(); |
| 279 | + tableMap.put(tableName, namedScan.getInitialSchema()); |
| 280 | + |
| 281 | + return result; |
| 282 | + } |
| 283 | + } |
| 284 | +} |
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