workload_generator: fix constraint prefix check

While extracting the table schemas from the create_statements file, we use a prefix-based check to identify whether a line has a column information or a constraint. This check fails in case the prefix of the column name matches. e.g.
a line beginning with "CHECK" is a constraint. But, if the column name is "checksum", this matches and causes an issue to identify the column as a constraint. To fix this, the check is changed to be "CHECK ". A TODO is added to use sql parser instead of this string match and regex logics.

Release Note: None
Epic: None

Author: nameisbhaskar

pkg/workload/workload_generator/schema_generator.go

@@ -353,6 +353,7 @@ func generateDDLFromCSV(
 // foreign keys, and check constraints) from the DDL statement and returns a structured
 // representation of the table schema.
 func ParseDDL(ddl string) (*TableSchema, error) {
+	// TODO: use sql parser instead of regexes.
 	tableMatch := tablePattern.FindStringSubmatch(ddl)
 	if tableMatch == nil {
 		return nil, errors.New("no table name")
@@ -439,7 +440,8 @@ func hasConstrainingPrefix(up string) bool {
 		sqlFamily,
 	}
 	for _, p := range prefixes {
-		if strings.HasPrefix(up, p) {
+		// a space is added after the prefix to avoid matches like "checksum" as a field name.
+		if strings.HasPrefix(up, p+" ") {
 			return true
 		}
 	}

pkg/workload/workload_generator/schema_generator_test.go

@@ -26,6 +26,7 @@ func TestSplitColumnDefsAndTableConstraints(t *testing.T) {
 		id INT PRIMARY KEY,
 		name TEXT NOT NULL,
 		age INT DEFAULT 30,
+		checksum BYTES DEFAULT 30,
 		CONSTRAINT user_pk PRIMARY KEY (id),
 		UNIQUE (name),
 		FOREIGN KEY (age) REFERENCES other(age),
@@ -36,6 +37,7 @@ func TestSplitColumnDefsAndTableConstraints(t *testing.T) {
 		"id INT PRIMARY KEY",
 		"name TEXT NOT NULL",
 		"age INT DEFAULT 30",
+		"checksum BYTES DEFAULT 30",
 	}
 	wantConstraints := []string{
 		"CONSTRAINT user_pk PRIMARY KEY (id)",