Added index.go

Author: joncrlsn

index.go

@@ -0,0 +1,101 @@
+package main
+
+import "fmt"
+import "database/sql"
+import "github.com/joncrlsn/pgutil"
+
+// IndexSchema holds a channel that streams index metadata from one of the databases.
+// It also holds a reference to the current row of data we're viewing.
+//
+// IndexSchema implements the Schema interface defined in pgdiff.go
+type IndexSchema struct {
+	channel chan map[string]string
+	row     map[string]string
+	done    bool
+}
+
+// NextRow reads from the channel and tells you if there are (probably) more or not
+func (c *IndexSchema) NextRow() bool {
+	c.row = <-c.channel
+	if len(c.row) == 0 {
+		c.done = true
+	}
+	return !c.done
+}
+
+// Compare tells you, in one pass, whether or not the first row matches, is less than, or greater than the second row
+func (c *IndexSchema) Compare(obj interface{}) int {
+	c2, ok := obj.(*IndexSchema)
+	if !ok {
+		fmt.Println("Error!!!, Change(...) needs a IndexSchema instance", c2)
+		return +999
+	}
+
+	//fmt.Printf("Comparing %s with %s", c.row["table_name"], c2.row["table_name"])
+	val := _compareString(c.row["table_name"], c2.row["table_name"])
+	if val != 0 {
+		return val
+	}
+
+	val = _compareString(c.row["index_name"], c2.row["index_name"])
+	return val
+}
+
+// Add generates SQL to add the index
+func (c IndexSchema) Add() {
+	uniqueStr := ""
+	if c.row["unique"] == "true" {
+		uniqueStr = "UNIQUE "
+	}
+	fmt.Printf("CREATE %sINDEX %s ON %s (%s);\n", uniqueStr, c.row["index_name"], c.row["table_name"], c.row["column_names"])
+}
+
+// Drop generates SQL to drop the index
+func (c IndexSchema) Drop() {
+	fmt.Printf("DROP INDEX %s;\n", c.row["index_name"])
+}
+
+// Change handles the case where the table and index name match, but the details do not
+func (c IndexSchema) Change(obj interface{}) {
+	c2, ok := obj.(*IndexSchema)
+	if !ok {
+		fmt.Println("Error!!!, change needs an IndexSchema instance", c2)
+	}
+	// No need to do anything, we either drop or add indices
+}
+
+/*
+ * Compare the columns in the two databases
+ */
+func compareIndexes(conn1 *sql.DB, conn2 *sql.DB) {
+	sql := `
+SELECT
+    t.relname AS table_name,
+    i.relname AS index_name,
+    ix.indisunique AS unique,
+    array_to_string(array_agg(a.attname), ', ') AS column_names
+FROM
+    pg_index AS ix,
+    pg_class AS t,
+    pg_class AS i,
+    pg_attribute AS a
+WHERE
+    t.oid = ix.indrelid
+    AND i.oid = ix.indexrelid
+    AND a.attrelid = t.oid
+    AND a.attnum = ANY(ix.indkey)
+    AND t.relkind = 'r'
+    AND t.relname not like 'pg_%'
+GROUP BY t.relname, i.relname, ix.indisunique
+ORDER BY t.relname, i.relname, ix.indisunique ASC;`
+
+	rowChan1, _ := pgutil.QueryStrings(conn1, sql)
+	rowChan2, _ := pgutil.QueryStrings(conn2, sql)
+
+	// We have to explicitly type this as Schema for some reason
+	var schema1 Schema = &IndexSchema{channel: rowChan1}
+	var schema2 Schema = &IndexSchema{channel: rowChan2}
+
+	// Compare the columns
+	doDiff(schema1, schema2)
+}

pgdiff.go

@@ -74,6 +74,8 @@ func main() {
 		comparePrimaryKeys(conn1, conn2)
 	} else if schemaType == "UNIQUE" {
 		compareUniqueConstraints(conn1, conn2)
+	} else if schemaType == "INDEX" {
+		compareIndexes(conn1, conn2)
 	} else if schemaType == "FOREIGN_KEY" {
 		compareForeignKeys(conn1, conn2)
 	} else {