[IGNITE-19066] Sql. Investigate why there is more than one instance of default value placeholder.

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Fix Version/s: 3.0
• Component/s: sql
• Labels: calcite3-required ignite-3
• Ignite Flags: Docs Required, Release Notes Required
• Assignee: Unassigned
• Reporter: Maksim Zhuravkov
• Created: 20/Mar/23 06:41
• Updated: 04/Sep/24 16:10

Description

Investigate why there is more than value of default value placeholder even though Default value placeholder implements readResolve method and it is uses java serialization.

Reproducer:

Update RexImpTable to use the following code for placeholders.

private static class Placeholder {
        static final Object DEFAULT_VALUE = DefaultValuePlaceholder.VALUE;
        static final Object UNSPECIFIED_VALUE = UnspecifiedValuePlaceholder.VALUE;
    }

    public static void ensurePlaceholderRemoved(Object value) {
        if (value instanceof DefaultValuePlaceholder && value != Placeholder.DEFAULT_VALUE) {
            throw new AssertionError("Unexpected DEFAULT value placeholder: " + value + ". Expected: " + Placeholder.DEFAULT_VALUE);
        }
    }

    private static final class DefaultValuePlaceholder implements Serializable {

        private static final DefaultValuePlaceholder VALUE = new DefaultValuePlaceholder();

        private static final long serialVersionUID = -978388731876609995L;

        private Object readResolve() {
            return VALUE;
        }

        public String toString() {
            return "DEFAULT#" + hashCode();
        }
    }

    private static final class UnspecifiedValuePlaceholder implements Serializable {

        private static final UnspecifiedValuePlaceholder VALUE = new UnspecifiedValuePlaceholder();

        private static final long serialVersionUID = 3312208611999510012L;

        private Object readResolve() {
            return VALUE;
        }

        public String toString() {
            return "<UNSPECIFIED_VALUE>";
        }
    }

Update IgniteTableImpl convertRow:

Object val = hnd.get(colDesc.logicalIndex(), row);
+ if (val != null) {
+  RexImpTable.ensurePlaceholderRemoved(val);
+ }

Error:

Caused by: java.lang.AssertionError: Unexpected DEFAULT value placeholder: DEFAULT#238068340. Expected: DEFAULT#1599919888
	at org.apache.ignite.internal.sql.engine.exec.exp.RexImpTable.ensurePlaceholderRemoved(RexImpTable.java:2588)
	at org.apache.ignite.internal.sql.engine.schema.IgniteTableImpl.convertRow(IgniteTableImpl.java:514)
	at org.apache.ignite.internal.sql.engine.schema.IgniteTableImpl.insertAll(IgniteTableImpl.java:390)
	at org.apache.ignite.internal.sql.engine.exec.rel.ModifyNode.flushTuples(ModifyNode.java:218)
	at org.apache.ignite.internal.sql.engine.exec.rel.ModifyNode.tryEnd(ModifyNode.java:187)
	at org.apache.ignite.internal.sql.engine.exec.rel.ModifyNode.end(ModifyNode.java:160)
	at org.apache.ignite.internal.sql.engine.exec.rel.Inbox.pushUnordered(Inbox.java:333)