hackergin commented on code in PR #22939:
URL: https://github.com/apache/flink/pull/22939#discussion_r1268198538
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flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/calcite/FlinkCalciteSqlValidator.java:
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@@ -125,4 +162,118 @@ public void validateColumnListParams(
// this makes it possible to ignore them in the validator and fall
back to regular row types
// see also SqlFunction#deriveType
}
+
+ @Override
+ protected void registerNamespace(
+ @Nullable SqlValidatorScope usingScope,
+ @Nullable String alias,
+ SqlValidatorNamespace ns,
+ boolean forceNullable) {
+
+ // Generate a new validator namespace for time travel scenario.
+ // Time travel only supports constant expressions, so we need to
investigate scenarios
+ // where the period of Snapshot is a SqlIdentifier.
+ Optional<SqlSnapshot> timeTravelNode = getTimeTravelNode(ns);
+ if (usingScope != null
+ && timeTravelNode.isPresent()
+ && !(timeTravelNode.get().getPeriod() instanceof
SqlIdentifier)) {
+ SqlSnapshot sqlSnapshot = timeTravelNode.get();
+ SqlNode periodNode = sqlSnapshot.getPeriod();
+ SqlToRelConverter sqlToRelConverter =
this.createSqlToRelConverter();
+ RexNode rexNode = sqlToRelConverter.convertExpression(periodNode);
+ RexNode simplifiedRexNode =
+ FlinkRexUtil.simplify(
+ sqlToRelConverter.getRexBuilder(),
+ rexNode,
+ relOptCluster.getPlanner().getExecutor());
+ List<RexNode> reducedNodes = new ArrayList<>();
+ relOptCluster
+ .getPlanner()
+ .getExecutor()
+ .reduce(
+ relOptCluster.getRexBuilder(),
+ Collections.singletonList(simplifiedRexNode),
+ reducedNodes);
+ // check whether period is the unsupported expression
+ if (!(reducedNodes.get(0) instanceof RexLiteral)) {
+ throw new UnsupportedOperationException(
+ String.format(
+ "Unsupported time travel expression: %s for
the expression can not be reduced to a constant by Flink.",
+ periodNode));
+ }
+
+ RexLiteral rexLiteral = (RexLiteral) (reducedNodes).get(0);
+ TimestampString timestampString =
rexLiteral.getValueAs(TimestampString.class);
+ checkNotNull(
+ timestampString,
+ "The time travel expression %s can not reduce to a valid
timestamp string. This is a bug. Please file an issue.",
+ periodNode);
+
+ TableConfig tableConfig =
ShortcutUtils.unwrapContext(relOptCluster).getTableConfig();
+ ZoneId zoneId = tableConfig.getLocalTimeZone();
+ long timeTravelTimestamp =
+
TimestampData.fromEpochMillis(timestampString.getMillisSinceEpoch())
+ .toLocalDateTime()
+ .atZone(zoneId)
+ .toInstant()
+ .toEpochMilli();
+
+ SchemaVersion schemaVersion =
TimestampSchemaVersion.of(timeTravelTimestamp);
+ IdentifierNamespace identifierNamespace = (IdentifierNamespace) ns;
+ IdentifierNamespace snapshotNameSpace =
+ new IdentifierSnapshotNamespace(
+ identifierNamespace,
+ schemaVersion,
+ ((DelegatingScope) usingScope).getParent());
+ ns = snapshotNameSpace;
+
+ sqlSnapshot.setOperand(
Review Comment:
Since we have reduce the period expression here, we can just build a simple
SqlLiteral. And we don't need to reduce again when convertting to RelNode.
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