add ListTableSizes and GetSize db method helpers

common.go

@@ -89,3 +89,27 @@ func QuerySingle[T any](ctx context.Context, db *DB, query string, args ...any)
 	err = db.QueryRow(ctx, query, args...).Scan(&entry)
 	return
 }
+
+func scanQuery[T any](ctx context.Context, db *DB, scanner func(rows Rows) (T, error), query string, args ...any) ([]T, error) {
+	rows, err := db.Query(ctx, query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var list []T
+
+	for rows.Next() {
+		entry, err := scanner(rows)
+		if err != nil {
+			return nil, err
+		}
+
+		list = append(list, entry)
+	}
+
+	if err = rows.Err(); err != nil && err != ErrNoRows {
+		return nil, err
+	}
+
+	return list, nil
+}

db_information.go

@@ -337,6 +337,64 @@ func (db *DB) GetVersion(ctx context.Context) (string, error) {
 	return versionNumber, nil // return the version number and nil as no error occurred
 }
 
+// SizeInfo is a struct which contains the size information (for individual table or the whole database).
+type SizeInfo struct {
+	SizePretty string `json:"size_pretty"`
+	// The on-disk size in bytes of one fork of that relation.
+	// A fork is a variant of the main data file that stores additional information,
+	// such as the free space map, the visibility map, or the initialization fork.
+	// By default, this is the size of the main data fork only.
+	Size float64 `json:"size"`
+
+	SizeTotalPretty string `json:"size_total_pretty"`
+	// The total on-disk space used for that table, including all associated indexes. This is equivalent to pg_table_size + pg_indexes_size.
+	SizeTotal float64 `json:"size_total"`
+}
+
+// TableSizeInfo is a struct which contains the table size information used as an output parameter of the `db.ListTableSizes` method.
+type TableSizeInfo struct {
+	TableName string `json:"table_name"`
+	SizeInfo
+}
+
+// ListTableSizes lists the disk size of tables (not only the registered ones) in the database.
+func (db *DB) ListTableSizes(ctx context.Context) ([]TableSizeInfo, error) {
+	query := `SELECT
+	table_name,
+	pg_size_pretty(pg_relation_size(quote_ident(table_name))) AS size_pretty,
+	pg_relation_size(quote_ident(table_name)) AS size,
+	  pg_size_pretty(pg_total_relation_size(quote_ident(table_name))) AS size_total_pretty,
+	  pg_total_relation_size(quote_ident(table_name)) AS size_total
+  FROM information_schema.tables
+  WHERE table_schema = $1
+  ORDER BY 3 DESC;`
+
+	return scanQuery[TableSizeInfo](ctx, db, func(rows Rows) (t TableSizeInfo, err error) {
+		err = rows.Scan(&t.TableName, &t.SizePretty, &t.Size, &t.SizeTotalPretty, &t.SizeTotal)
+		return
+	}, query, db.searchPath)
+}
+
+// GetSize returns the sum of size of all the database tables.
+func (db *DB) GetSize(ctx context.Context) (t SizeInfo, err error) {
+	query := `SELECT
+	 pg_size_pretty(SUM(size)) AS size_pretty,
+	 SUM(size) AS size, pg_size_pretty(SUM(size_total)) AS size_total_pretty,
+	 SUM(size_total) AS size_total
+	 FROM (
+		SELECT
+		  table_name,
+		  pg_relation_size(quote_ident(table_name)) AS size,
+			pg_total_relation_size(quote_ident(table_name)) AS size_total
+		FROM information_schema.tables
+		WHERE table_schema = $1
+		ORDER BY 1 DESC
+	) f;`
+
+	err = db.QueryRow(ctx, query, db.searchPath).Scan(&t.SizePretty, &t.Size, &t.SizeTotalPretty, &t.SizeTotal)
+	return
+}
+
 // MapTypeFilter is a map of expressions inputs text to field type.
 // It's a TableFilter.
 //

go.mod

@@ -5,14 +5,14 @@ go 1.21
 require (
 	github.com/gertd/go-pluralize v0.2.1
 	github.com/jackc/pgx/v5 v5.4.3
-	golang.org/x/mod v0.12.0
+	golang.org/x/mod v0.13.0
 )
 
 require (
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a // indirect
 	github.com/jackc/puddle/v2 v2.2.1 // indirect
-	golang.org/x/crypto v0.13.0 // indirect
-	golang.org/x/sync v0.3.0 // indirect
+	golang.org/x/crypto v0.14.0 // indirect
+	golang.org/x/sync v0.4.0 // indirect
 	golang.org/x/text v0.13.0 // indirect
 )

go.sum

@@ -18,12 +18,12 @@ github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UV
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
-golang.org/x/crypto v0.13.0 h1:mvySKfSWJ+UKUii46M40LOvyWfN0s2U+46/jDd0e6Ck=
-golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
-golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
-golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
-golang.org/x/sync v0.3.0 h1:ftCYgMx6zT/asHUrPw8BLLscYtGznsLAnjq5RH9P66E=
-golang.org/x/sync v0.3.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/crypto v0.14.0 h1:wBqGXzWJW6m1XrIKlAH0Hs1JJ7+9KBwnIO8v66Q9cHc=
+golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
+golang.org/x/mod v0.13.0 h1:I/DsJXRlw/8l/0c24sM9yb0T4z9liZTduXvdAWYiysY=
+golang.org/x/mod v0.13.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.4.0 h1:zxkM55ReGkDlKSM+Fu41A+zmbZuaPVbGMzvvdUPznYQ=
+golang.org/x/sync v0.4.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
 golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
 golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=