What causes "TODO:insert into .... select .... not supported!" in MyCATApache/Mycat-Server?

Rewrite as a plain INSERT with explicit VALUES

MyCATApache/Mycat-Server · warning · SQLNonTransientException

TODO:insert into .... select .... not supported!

Error message

TODO:insert into .... select .... not supported!

What it means

DruidInsertParser does not implement routing for INSERT INTO ... SELECT statements. When the parsed SQLInsertStatement has a query part (a SELECT source instead of VALUES), it throws SQLNonTransientException with a literal TODO message.

Solutions

Rewrite as a plain INSERT with explicit VALUES
Split into SELECT first, then INSERT per row from the application
Execute the INSERT...SELECT directly on the datanode's MySQL, bypassing MyCat routing
Upgrade MyCat versions — check release notes for INSERT-SELECT support

Example fix

// before
INSERT INTO t SELECT id, name FROM src;
// after
SELECT id, name FROM src; -- then INSERT INTO t VALUES (...) per row from client

Defensive patterns

Strategy: try-catch

Validate before calling

if (sql.matches("(?is)\\s*insert\\s+.*\\bselect\\b.*")) throw new UnsupportedSqlException("INSERT...SELECT not supported by MyCat router");

Try / catch

try { route(sql); } catch (SQLNonTransientException e) { if (e.getMessage().contains("insert into .... select")) { fallbackToClientSideInsert(sql); } else throw e; }

Prevention

Ban INSERT...SELECT in code review for MyCat-fronted schemas
Implement ETL copy logic in the application instead of SQL
Document the limitation for DBAs writing migration scripts

When it happens

Trigger: statementParse -> parserBatchInsert (or the insert parse path) receives `INSERT INTO t SELECT ...` — insertStmt.getQuery() != null.

Common situations: Migration scripts using INSERT...SELECT to copy data; ORM or ETL tools generating INSERT-SELECT; developers assuming MyCat passes arbitrary SQL through to MySQL.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of MyCATApache/Mycat-Server@65f8d8beb7 (2026-09-11). Data as JSON: /api/errors/372675f16c9635d2. Report an issue: GitHub.

Appendix: source

Thrown at src/main/java/io/mycat/route/parser/druid/impl/DruidInsertParser.java:324

						nodes[count] = new RouteResultsetNode(tableConfig.getDataNodes().get(nodeIndex),
								rrs.getSqlType(),insertStmt.toString());
					}
					
					if(algorithm instanceof SlotFunction) {
						nodes[count].setSlot(slotsMap.get(nodeIndex));
						nodes[count].setStatement(ParseUtil.changeInsertAddSlot(nodes[count].getStatement(),nodes[count].getSlot()));
					}
					nodes[count++].setSource(rrs);

				}
				rrs.setNodes(nodes);
				rrs.setFinishedRoute(true);

			}
		} else if(insertStmt.getQuery() != null) { // insert into .... select ....
			String msg = "TODO:insert into .... select .... not supported!";
			LOGGER.warn(msg);
			throw new SQLNonTransientException(msg);
		}
	}

	private String getShardingValue(SQLExpr expr) throws SQLNonTransientException {
		String shardingValue = null;
		if(expr instanceof SQLIntegerExpr) {
			SQLIntegerExpr intExpr = (SQLIntegerExpr)expr;
			shardingValue = intExpr.getNumber() + "";
		} else if (expr instanceof SQLCharExpr) {
			SQLCharExpr charExpr = (SQLCharExpr)expr;
			shardingValue = charExpr.getText();
		} else if (expr instanceof SQLMethodInvokeExpr) {
			SQLMethodInvokeExpr methodInvokeExpr = (SQLMethodInvokeExpr)expr;
			try {
				shardingValue = tryInvokeSQLMethod(methodInvokeExpr);
			}catch (Exception e){
				LOGGER.error("",e);
			}

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