/**
* This method behaves similarly to parse(), but allows the caller to pass in XML to avoid
* re-parsing SQL text that has already gone through HSQL.
*
* @param xmlSql XML produced by previous invocation of HSQL
*/
public void parseFromXml(VoltXMLElement xmlSQL) {
m_recentErrorMsg = null;
m_xmlSQL = xmlSQL;
if (m_xmlSQL.attributes.containsKey(UPSERT_TAG)) {
m_isUpsert = true;
}
m_planSelector.outputCompiledStatement(m_xmlSQL);
}
/**
* Auto-parameterize all of the literals in the parsed SQL statement.
*
* @return An opaque token representing the parsed statement with (possibly) parameterization.
*/
public String parameterize() {
m_paramzInfo = ParameterizationInfo.parameterize(m_xmlSQL);
Set<Integer> paramIds = new HashSet<Integer>();
ParameterizationInfo.findUserParametersRecursively(m_xmlSQL, paramIds);
m_adhocUserParamsCount = paramIds.size();
// skip plans with pre-existing parameters and plans that don't parameterize
// assume a user knows how to cache/optimize these
if (m_paramzInfo != null) {
// if requested output the second version of the parsed plan
m_planSelector.outputParameterizedCompiledStatement(m_paramzInfo.parameterizedXmlSQL);
return m_paramzInfo.parameterizedXmlSQL.toMinString();
}
// fallback when parameterization is
return m_xmlSQL.toMinString();
}
/**
* Parse a SQL literal statement into an unplanned, intermediate representation. This is normally
* followed by a call to {@link this#plan(AbstractCostModel, String, String, String, String, int,
* ScalarValueHints[]) }, but splitting these two affords an opportunity to check a cache for a
* plan matching the auto-parameterized parsed statement.
*/
public void parse() throws PlanningErrorException {
// reset any error message
m_recentErrorMsg = null;
// Reset plan node ids to start at 1 for this plan
AbstractPlanNode.resetPlanNodeIds();
// determine the type of the query
//
// (Hmmm... seems like this pre-processing of the SQL text
// and subsequent placement of UPSERT_TAG should be pushed down
// into getXMLCompiledStatement)
m_sql = m_sql.trim();
if (m_sql.length() > 6
&& m_sql.substring(0, 6).toUpperCase().startsWith("UPSERT")) { // ENG-7395
m_isUpsert = true;
m_sql = "INSERT" + m_sql.substring(6);
}
// use HSQLDB to get XML that describes the semantics of the statement
// this is much easier to parse than SQL and is checked against the catalog
try {
m_xmlSQL = m_HSQL.getXMLCompiledStatement(m_sql);
} catch (HSQLParseException e) {
// XXXLOG probably want a real log message here
throw new PlanningErrorException(e.getMessage());
}
if (m_isUpsert) {
assert (m_xmlSQL.name.equalsIgnoreCase("INSERT"));
// for AdHoc cache distinguish purpose which is based on the XML
m_xmlSQL.attributes.put(UPSERT_TAG, "true");
}
m_planSelector.outputCompiledStatement(m_xmlSQL);
}
private CompiledPlan compileFromXML(VoltXMLElement xmlSQL, String[] paramValues) {
// Get a parsed statement from the xml
// The callers of compilePlan are ready to catch any exceptions thrown here.
AbstractParsedStmt parsedStmt =
AbstractParsedStmt.parse(m_sql, xmlSQL, paramValues, m_db, m_joinOrder);
if (parsedStmt == null) {
m_recentErrorMsg = "Failed to parse SQL statement: " + getOriginalSql();
return null;
}
if (m_isUpsert) {
// no insert/upsert with joins
if (parsedStmt.m_tableList.size() != 1) {
m_recentErrorMsg = "UPSERT is support only with one single table: " + getOriginalSql();
return null;
}
Table tb = parsedStmt.m_tableList.get(0);
Constraint pkey = null;
for (Constraint ct : tb.getConstraints()) {
if (ct.getType() == ConstraintType.PRIMARY_KEY.getValue()) {
pkey = ct;
break;
}
}
if (pkey == null) {
m_recentErrorMsg = "Unsupported UPSERT table without primary key: " + getOriginalSql();
return null;
}
}
m_planSelector.outputParsedStatement(parsedStmt);
// Init Assembler. Each plan assembler requires a new instance of the PlanSelector
// to keep track of the best plan
PlanAssembler assembler =
new PlanAssembler(m_cluster, m_db, m_partitioning, (PlanSelector) m_planSelector.clone());
// find the plan with minimal cost
CompiledPlan bestPlan = assembler.getBestCostPlan(parsedStmt);
// This processing of bestPlan outside/after getBestCostPlan
// allows getBestCostPlan to be called both here and
// in PlanAssembler.getNextUnion on each branch of a union.
// make sure we got a winner
if (bestPlan == null) {
if (m_debuggingStaticModeToRetryOnError) {
assembler.getBestCostPlan(parsedStmt);
}
m_recentErrorMsg = assembler.getErrorMessage();
if (m_recentErrorMsg == null) {
m_recentErrorMsg = "Unable to plan for statement. Error unknown.";
}
return null;
}
if (bestPlan.isReadOnly()) {
SendPlanNode sendNode = new SendPlanNode();
// connect the nodes to build the graph
sendNode.addAndLinkChild(bestPlan.rootPlanGraph);
// this plan is final, generate schema and resolve all the column index references
bestPlan.rootPlanGraph = sendNode;
}
// Execute the generateOutputSchema and resolveColumnIndexes once for the best plan
bestPlan.rootPlanGraph.generateOutputSchema(m_db);
bestPlan.rootPlanGraph.resolveColumnIndexes();
if (parsedStmt instanceof ParsedSelectStmt) {
List<SchemaColumn> columns = bestPlan.rootPlanGraph.getOutputSchema().getColumns();
((ParsedSelectStmt) parsedStmt).checkPlanColumnMatch(columns);
}
// Output the best plan debug info
assembler.finalizeBestCostPlan();
// reset all the plan node ids for a given plan
// this makes the ids deterministic
bestPlan.resetPlanNodeIds(1);
// split up the plan everywhere we see send/recieve into multiple plan fragments
List<AbstractPlanNode> receives =
bestPlan.rootPlanGraph.findAllNodesOfClass(AbstractReceivePlanNode.class);
if (receives.size() > 1) {
// Have too many receive node for two fragment plan limit
m_recentErrorMsg =
"This join of multiple partitioned tables is too complex. "
+ "Consider simplifying its subqueries: "
+ getOriginalSql();
return null;
}
/*/ enable for debug ...
if (receives.size() > 1) {
System.out.println(plan.rootPlanGraph.toExplainPlanString());
}
// ... enable for debug */
if (receives.size() == 1) {
AbstractReceivePlanNode recvNode = (AbstractReceivePlanNode) receives.get(0);
fragmentize(bestPlan, recvNode);
}
return bestPlan;
}
