bamaer commented on code in PR #8849:
URL: https://github.com/apache/hop/pull/8849#discussion_r4245112115
##########
plugins/tech/age/src/main/java/org/apache/hop/age/AgeGraphDialect.java:
##########
@@ -45,6 +50,82 @@ public String toString() {
return getId();
}
+ @Override
+ public boolean isSupportingNodeIndexes() {
+ return true;
+ }
+
+ /**
+ * Create the label if it doesn't exist yet, then the index on its table:
the index can be created
+ * before the nodes are loaded.
+ */
+ @Override
+ public String getCreateIndexStatement(GraphIndexDefinition index) throws
HopException {
+ validateIndex(index);
+ if (index.properties().isEmpty()) {
+ throw new HopException("Please specify the properties to index on " +
index.objectName());
+ }
+ return getCreateLabelStatement(index.objectName())
+ + ";\n"
+ + getCreateNodeIndexStatement(index.name(), index.objectName(),
index.properties());
+ }
+
+ @Override
+ public String getDropIndexStatement(GraphIndexDefinition index) throws
HopException {
+ validateIndex(index);
+ return "DROP INDEX IF EXISTS "
+ + quoteIdentifier(graphName)
+ + '.'
+ + quoteIdentifier(index.name());
+ }
+
+ /** Only named indexes on nodes: PostgreSQL needs the name to create the
index if not exists. */
+ private void validateIndex(GraphIndexDefinition index) throws HopException {
+ if (index.isRelationship()) {
+ throw IGraphDialect.indexesNotSupported(this, index.objectType(),
index.objectName());
+ }
+ if (StringUtils.isEmpty(index.objectName())) {
+ throw new HopException("Please specify the label of the index " +
index.name());
+ }
+ if (StringUtils.isEmpty(index.name())) {
+ throw new HopException(
+ "Apache AGE indexes need a name. Label: "
+ + index.objectName()
+ + ", properties: "
+ + String.join(",", index.properties()));
+ }
+ }
+
+ /**
+ * A block creating the node label in the graph unless it exists: AGE
creates the table of a label
+ * with the first node.
+ */
+ String getCreateLabelStatement(String label) {
+ String graphLiteral = quoteLiteral(graphName);
+ String labelLiteral = quoteLiteral(label);
+ String body =
+ "BEGIN IF NOT EXISTS (SELECT 1 FROM ag_catalog.ag_label l"
+ + " JOIN ag_catalog.ag_graph g ON g.graphid = l.graph WHERE g.name
= "
+ + graphLiteral
+ + " AND l.kind = 'v' AND l.name = "
+ + labelLiteral
+ + ") THEN PERFORM ag_catalog.create_vlabel("
Review Comment:
Thanks @mattcasters, good catch. Confirmed against
`apache/age:release_PG18_1.8.0`: with one session holding the new label in an
open transaction, the second one failed with `relation "…" already exists` and
skipped the index.
Fixed by wrapping `create_vlabel` in its own `EXCEPTION` block that
re-checks `ag_label`. If the label exists by then, it carries on with `CREATE
INDEX IF NOT EXISTS`; otherwise it re-raises. That's the same approach as
`createGraphIfMissing`. The same two-session test now creates the index, and a
real error (e.g. a missing graph) still fails.
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