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metadata_scylla.go
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metadata_scylla.go
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//go:build !cassandra || scylla
// +build !cassandra scylla
// Copyright (c) 2015 The gocql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gocql
import (
"fmt"
"strings"
"sync"
)
// schema metadata for a keyspace
type KeyspaceMetadata struct {
Name string
DurableWrites bool
StrategyClass string
StrategyOptions map[string]interface{}
Tables map[string]*TableMetadata
Functions map[string]*FunctionMetadata
Aggregates map[string]*AggregateMetadata
Types map[string]*TypeMetadata
Indexes map[string]*IndexMetadata
Views map[string]*ViewMetadata
}
// schema metadata for a table (a.k.a. column family)
type TableMetadata struct {
Keyspace string
Name string
PartitionKey []*ColumnMetadata
ClusteringColumns []*ColumnMetadata
Columns map[string]*ColumnMetadata
OrderedColumns []string
Options TableMetadataOptions
Flags []string
Extensions map[string]interface{}
}
type TableMetadataOptions struct {
BloomFilterFpChance float64
Caching map[string]string
Comment string
Compaction map[string]string
Compression map[string]string
CrcCheckChance float64
DcLocalReadRepairChance float64
DefaultTimeToLive int
GcGraceSeconds int
MaxIndexInterval int
MemtableFlushPeriodInMs int
MinIndexInterval int
ReadRepairChance float64
SpeculativeRetry string
CDC map[string]string
InMemory bool
Partitioner string
Version string
}
type ViewMetadata struct {
KeyspaceName string
ViewName string
BaseTableID string
BaseTableName string
ID string
IncludeAllColumns bool
Columns map[string]*ColumnMetadata
OrderedColumns []string
PartitionKey []*ColumnMetadata
ClusteringColumns []*ColumnMetadata
WhereClause string
Options TableMetadataOptions
Extensions map[string]interface{}
}
// schema metadata for a column
type ColumnMetadata struct {
Keyspace string
Table string
Name string
ComponentIndex int
Kind ColumnKind
Type string
ClusteringOrder string
Order ColumnOrder
Index ColumnIndexMetadata
}
// FunctionMetadata holds metadata for function constructs
type FunctionMetadata struct {
Keyspace string
Name string
ArgumentTypes []string
ArgumentNames []string
Body string
CalledOnNullInput bool
Language string
ReturnType string
}
// AggregateMetadata holds metadata for aggregate constructs
type AggregateMetadata struct {
Keyspace string
Name string
ArgumentTypes []string
FinalFunc FunctionMetadata
InitCond string
ReturnType string
StateFunc FunctionMetadata
StateType string
stateFunc string
finalFunc string
}
// TypeMetadata holds the metadata for views.
type TypeMetadata struct {
Keyspace string
Name string
FieldNames []string
FieldTypes []string
}
type IndexMetadata struct {
Name string
KeyspaceName string
TableName string
Kind string
Options map[string]string
}
const (
IndexKindCustom = "CUSTOM"
)
const (
TableFlagDense = "dense"
TableFlagSuper = "super"
TableFlagCompound = "compound"
)
// the ordering of the column with regard to its comparator
type ColumnOrder bool
const (
ASC ColumnOrder = false
DESC = true
)
type ColumnIndexMetadata struct {
Name string
Type string
Options map[string]interface{}
}
type ColumnKind int
const (
ColumnUnkownKind ColumnKind = iota
ColumnPartitionKey
ColumnClusteringKey
ColumnRegular
ColumnCompact
ColumnStatic
)
func (c ColumnKind) String() string {
switch c {
case ColumnPartitionKey:
return "partition_key"
case ColumnClusteringKey:
return "clustering_key"
case ColumnRegular:
return "regular"
case ColumnCompact:
return "compact"
case ColumnStatic:
return "static"
default:
return fmt.Sprintf("unknown_column_%d", c)
}
}
func (c *ColumnKind) UnmarshalCQL(typ TypeInfo, p []byte) error {
if typ.Type() != TypeVarchar {
return unmarshalErrorf("unable to marshall %s into ColumnKind, expected Varchar", typ)
}
kind, err := columnKindFromSchema(string(p))
if err != nil {
return err
}
*c = kind
return nil
}
func columnKindFromSchema(kind string) (ColumnKind, error) {
switch kind {
case "partition_key":
return ColumnPartitionKey, nil
case "clustering_key", "clustering":
return ColumnClusteringKey, nil
case "regular":
return ColumnRegular, nil
case "compact_value":
return ColumnCompact, nil
case "static":
return ColumnStatic, nil
default:
return -1, fmt.Errorf("unknown column kind: %q", kind)
}
}
// queries the cluster for schema information for a specific keyspace
type schemaDescriber struct {
session *Session
mu sync.Mutex
cache map[string]*KeyspaceMetadata
}
// creates a session bound schema describer which will query and cache
// keyspace metadata
func newSchemaDescriber(session *Session) *schemaDescriber {
return &schemaDescriber{
session: session,
cache: map[string]*KeyspaceMetadata{},
}
}
// returns the cached KeyspaceMetadata held by the describer for the named
// keyspace.
func (s *schemaDescriber) getSchema(keyspaceName string) (*KeyspaceMetadata, error) {
s.mu.Lock()
defer s.mu.Unlock()
metadata, found := s.cache[keyspaceName]
if !found {
// refresh the cache for this keyspace
err := s.refreshSchema(keyspaceName)
if err != nil {
return nil, err
}
metadata = s.cache[keyspaceName]
}
return metadata, nil
}
// clears the already cached keyspace metadata
func (s *schemaDescriber) clearSchema(keyspaceName string) {
s.mu.Lock()
defer s.mu.Unlock()
delete(s.cache, keyspaceName)
}
// forcibly updates the current KeyspaceMetadata held by the schema describer
// for a given named keyspace.
func (s *schemaDescriber) refreshSchema(keyspaceName string) error {
var err error
// query the system keyspace for schema data
// TODO retrieve concurrently
keyspace, err := getKeyspaceMetadata(s.session, keyspaceName)
if err != nil {
return err
}
tables, err := getTableMetadata(s.session, keyspaceName)
if err != nil {
return err
}
columns, err := getColumnMetadata(s.session, keyspaceName)
if err != nil {
return err
}
functions, err := getFunctionsMetadata(s.session, keyspaceName)
if err != nil {
return err
}
aggregates, err := getAggregatesMetadata(s.session, keyspaceName)
if err != nil {
return err
}
types, err := getTypeMetadata(s.session, keyspaceName)
if err != nil {
return err
}
indexes, err := getIndexMetadata(s.session, keyspaceName)
if err != nil {
return err
}
views, err := getViewMetadata(s.session, keyspaceName)
if err != nil {
return err
}
// organize the schema data
compileMetadata(keyspace, tables, columns, functions, aggregates, types, indexes, views)
// update the cache
s.cache[keyspaceName] = keyspace
return nil
}
// "compiles" derived information about keyspace, table, and column metadata
// for a keyspace from the basic queried metadata objects returned by
// getKeyspaceMetadata, getTableMetadata, and getColumnMetadata respectively;
// Links the metadata objects together and derives the column composition of
// the partition key and clustering key for a table.
func compileMetadata(
keyspace *KeyspaceMetadata,
tables []TableMetadata,
columns []ColumnMetadata,
functions []FunctionMetadata,
aggregates []AggregateMetadata,
types []TypeMetadata,
indexes []IndexMetadata,
views []ViewMetadata,
) {
keyspace.Tables = make(map[string]*TableMetadata)
for i := range tables {
tables[i].Columns = make(map[string]*ColumnMetadata)
keyspace.Tables[tables[i].Name] = &tables[i]
}
keyspace.Functions = make(map[string]*FunctionMetadata, len(functions))
for i := range functions {
keyspace.Functions[functions[i].Name] = &functions[i]
}
keyspace.Aggregates = make(map[string]*AggregateMetadata, len(aggregates))
for _, aggregate := range aggregates {
aggregate.FinalFunc = *keyspace.Functions[aggregate.finalFunc]
aggregate.StateFunc = *keyspace.Functions[aggregate.stateFunc]
keyspace.Aggregates[aggregate.Name] = &aggregate
}
keyspace.Types = make(map[string]*TypeMetadata, len(types))
for i := range types {
keyspace.Types[types[i].Name] = &types[i]
}
keyspace.Indexes = make(map[string]*IndexMetadata, len(indexes))
for i := range indexes {
keyspace.Indexes[indexes[i].Name] = &indexes[i]
}
keyspace.Views = make(map[string]*ViewMetadata, len(views))
for i := range views {
v := &views[i]
if _, ok := keyspace.Indexes[strings.TrimSuffix(v.ViewName, "_index")]; ok {
continue
}
v.Columns = make(map[string]*ColumnMetadata)
keyspace.Views[v.ViewName] = v
}
// add columns from the schema data
for i := range columns {
col := &columns[i]
col.Order = ASC
if col.ClusteringOrder == "desc" {
col.Order = DESC
}
table, ok := keyspace.Tables[col.Table]
if !ok {
view, ok := keyspace.Views[col.Table]
if !ok {
// if the schema is being updated we will race between seeing
// the metadata be complete. Potentially we should check for
// schema versions before and after reading the metadata and
// if they dont match try again.
continue
}
view.Columns[col.Name] = col
view.OrderedColumns = append(view.OrderedColumns, col.Name)
continue
}
table.Columns[col.Name] = col
table.OrderedColumns = append(table.OrderedColumns, col.Name)
}
for i := range tables {
t := &tables[i]
t.PartitionKey, t.ClusteringColumns, t.OrderedColumns = compileColumns(t.Columns, t.OrderedColumns)
}
for i := range views {
v := &views[i]
v.PartitionKey, v.ClusteringColumns, v.OrderedColumns = compileColumns(v.Columns, v.OrderedColumns)
}
}
func compileColumns(columns map[string]*ColumnMetadata, orderedColumns []string) (
partitionKey, clusteringColumns []*ColumnMetadata, sortedColumns []string) {
clusteringColumnCount := componentColumnCountOfType(columns, ColumnClusteringKey)
clusteringColumns = make([]*ColumnMetadata, clusteringColumnCount)
partitionKeyCount := componentColumnCountOfType(columns, ColumnPartitionKey)
partitionKey = make([]*ColumnMetadata, partitionKeyCount)
var otherColumns []string
for _, columnName := range orderedColumns {
column := columns[columnName]
if column.Kind == ColumnPartitionKey {
partitionKey[column.ComponentIndex] = column
} else if column.Kind == ColumnClusteringKey {
clusteringColumns[column.ComponentIndex] = column
} else {
otherColumns = append(otherColumns, columnName)
}
}
sortedColumns = orderedColumns[:0]
for _, pk := range partitionKey {
sortedColumns = append(sortedColumns, pk.Name)
}
for _, ck := range clusteringColumns {
sortedColumns = append(sortedColumns, ck.Name)
}
for _, oc := range otherColumns {
sortedColumns = append(sortedColumns, oc)
}
return
}
// returns the count of coluns with the given "kind" value.
func componentColumnCountOfType(columns map[string]*ColumnMetadata, kind ColumnKind) int {
maxComponentIndex := -1
for _, column := range columns {
if column.Kind == kind && column.ComponentIndex > maxComponentIndex {
maxComponentIndex = column.ComponentIndex
}
}
return maxComponentIndex + 1
}
// query for keyspace metadata in the system_schema.keyspaces
func getKeyspaceMetadata(session *Session, keyspaceName string) (*KeyspaceMetadata, error) {
if !session.useSystemSchema {
return nil, ErrKeyspaceDoesNotExist
}
keyspace := &KeyspaceMetadata{Name: keyspaceName}
const stmt = `
SELECT durable_writes, replication
FROM system_schema.keyspaces
WHERE keyspace_name = ?`
var replication map[string]string
iter := session.control.query(stmt, keyspaceName)
if iter.NumRows() == 0 {
return nil, ErrKeyspaceDoesNotExist
}
iter.Scan(&keyspace.DurableWrites, &replication)
err := iter.Close()
if err != nil {
return nil, fmt.Errorf("error querying keyspace schema: %v", err)
}
keyspace.StrategyClass = replication["class"]
delete(replication, "class")
keyspace.StrategyOptions = make(map[string]interface{}, len(replication))
for k, v := range replication {
keyspace.StrategyOptions[k] = v
}
return keyspace, nil
}
// query for table metadata in the system_schema.tables and system_schema.scylla_tables
func getTableMetadata(session *Session, keyspaceName string) ([]TableMetadata, error) {
if !session.useSystemSchema {
return nil, nil
}
stmt := `SELECT * FROM system_schema.tables WHERE keyspace_name = ?`
iter := session.control.query(stmt, keyspaceName)
var tables []TableMetadata
table := TableMetadata{Keyspace: keyspaceName}
for iter.MapScan(map[string]interface{}{
"table_name": &table.Name,
"bloom_filter_fp_chance": &table.Options.BloomFilterFpChance,
"caching": &table.Options.Caching,
"comment": &table.Options.Comment,
"compaction": &table.Options.Compaction,
"compression": &table.Options.Compression,
"crc_check_chance": &table.Options.CrcCheckChance,
"dclocal_read_repair_chance": &table.Options.DcLocalReadRepairChance,
"default_time_to_live": &table.Options.DefaultTimeToLive,
"gc_grace_seconds": &table.Options.GcGraceSeconds,
"max_index_interval": &table.Options.MaxIndexInterval,
"memtable_flush_period_in_ms": &table.Options.MemtableFlushPeriodInMs,
"min_index_interval": &table.Options.MinIndexInterval,
"read_repair_chance": &table.Options.ReadRepairChance,
"speculative_retry": &table.Options.SpeculativeRetry,
"flags": &table.Flags,
"extensions": &table.Extensions,
}) {
tables = append(tables, table)
table = TableMetadata{Keyspace: keyspaceName}
}
err := iter.Close()
if err != nil && err != ErrNotFound {
return nil, fmt.Errorf("error querying table schema: %v", err)
}
stmt = `SELECT * FROM system_schema.scylla_tables WHERE keyspace_name = ? AND table_name = ?`
for i, t := range tables {
iter := session.control.query(stmt, keyspaceName, t.Name)
table := TableMetadata{}
if iter.MapScan(map[string]interface{}{
"cdc": &table.Options.CDC,
"in_memory": &table.Options.InMemory,
"partitioner": &table.Options.Partitioner,
"version": &table.Options.Version,
}) {
tables[i].Options.CDC = table.Options.CDC
tables[i].Options.Version = table.Options.Version
tables[i].Options.Partitioner = table.Options.Partitioner
tables[i].Options.InMemory = table.Options.InMemory
}
if err := iter.Close(); err != nil && err != ErrNotFound {
return nil, fmt.Errorf("error querying scylla table schema: %v", err)
}
}
return tables, nil
}
// query for column metadata in the system_schema.columns
func getColumnMetadata(session *Session, keyspaceName string) ([]ColumnMetadata, error) {
const stmt = `SELECT * FROM system_schema.columns WHERE keyspace_name = ?`
var columns []ColumnMetadata
iter := session.control.query(stmt, keyspaceName)
column := ColumnMetadata{Keyspace: keyspaceName}
for iter.MapScan(map[string]interface{}{
"table_name": &column.Table,
"column_name": &column.Name,
"clustering_order": &column.ClusteringOrder,
"type": &column.Type,
"kind": &column.Kind,
"position": &column.ComponentIndex,
}) {
columns = append(columns, column)
column = ColumnMetadata{Keyspace: keyspaceName}
}
if err := iter.Close(); err != nil && err != ErrNotFound {
return nil, fmt.Errorf("error querying column schema: %v", err)
}
return columns, nil
}
// query for type metadata in the system_schema.types
func getTypeMetadata(session *Session, keyspaceName string) ([]TypeMetadata, error) {
if !session.useSystemSchema {
return nil, nil
}
stmt := `SELECT * FROM system_schema.types WHERE keyspace_name = ?`
iter := session.control.query(stmt, keyspaceName)
var types []TypeMetadata
tm := TypeMetadata{Keyspace: keyspaceName}
for iter.MapScan(map[string]interface{}{
"type_name": &tm.Name,
"field_names": &tm.FieldNames,
"field_types": &tm.FieldTypes,
}) {
types = append(types, tm)
tm = TypeMetadata{Keyspace: keyspaceName}
}
if err := iter.Close(); err != nil {
return nil, err
}
return types, nil
}
// query for function metadata in the system_schema.functions
func getFunctionsMetadata(session *Session, keyspaceName string) ([]FunctionMetadata, error) {
if !session.hasAggregatesAndFunctions || !session.useSystemSchema {
return nil, nil
}
stmt := `SELECT * FROM system_schema.functions WHERE keyspace_name = ?`
var functions []FunctionMetadata
function := FunctionMetadata{Keyspace: keyspaceName}
iter := session.control.query(stmt, keyspaceName)
for iter.MapScan(map[string]interface{}{
"function_name": &function.Name,
"argument_types": &function.ArgumentTypes,
"argument_names": &function.ArgumentNames,
"body": &function.Body,
"called_on_null_input": &function.CalledOnNullInput,
"language": &function.Language,
"return_type": &function.ReturnType,
}) {
functions = append(functions, function)
function = FunctionMetadata{Keyspace: keyspaceName}
}
if err := iter.Close(); err != nil {
return nil, err
}
return functions, nil
}
// query for aggregate metadata in the system_schema.aggregates
func getAggregatesMetadata(session *Session, keyspaceName string) ([]AggregateMetadata, error) {
if !session.hasAggregatesAndFunctions || !session.useSystemSchema {
return nil, nil
}
const stmt = `SELECT * FROM system_schema.aggregates WHERE keyspace_name = ?`
var aggregates []AggregateMetadata
aggregate := AggregateMetadata{Keyspace: keyspaceName}
iter := session.control.query(stmt, keyspaceName)
for iter.MapScan(map[string]interface{}{
"aggregate_name": &aggregate.Name,
"argument_types": &aggregate.ArgumentTypes,
"final_func": &aggregate.finalFunc,
"initcond": &aggregate.InitCond,
"return_type": &aggregate.ReturnType,
"state_func": &aggregate.stateFunc,
"state_type": &aggregate.StateType,
}) {
aggregates = append(aggregates, aggregate)
aggregate = AggregateMetadata{Keyspace: keyspaceName}
}
if err := iter.Close(); err != nil {
return nil, err
}
return aggregates, nil
}
// query for index metadata in the system_schema.indexes
func getIndexMetadata(session *Session, keyspaceName string) ([]IndexMetadata, error) {
if !session.useSystemSchema {
return nil, nil
}
const stmt = `SELECT * FROM system_schema.indexes WHERE keyspace_name = ?`
var indexes []IndexMetadata
index := IndexMetadata{}
iter := session.control.query(stmt, keyspaceName)
for iter.MapScan(map[string]interface{}{
"index_name": &index.Name,
"keyspace_name": &index.KeyspaceName,
"table_name": &index.TableName,
"kind": &index.Kind,
"options": &index.Options,
}) {
indexes = append(indexes, index)
index = IndexMetadata{}
}
if err := iter.Close(); err != nil {
return nil, err
}
return indexes, nil
}
// query for view metadata in the system_schema.views
func getViewMetadata(session *Session, keyspaceName string) ([]ViewMetadata, error) {
if !session.useSystemSchema {
return nil, nil
}
stmt := `SELECT * FROM system_schema.views WHERE keyspace_name = ?`
iter := session.control.query(stmt, keyspaceName)
var views []ViewMetadata
view := ViewMetadata{KeyspaceName: keyspaceName}
for iter.MapScan(map[string]interface{}{
"id": &view.ID,
"view_name": &view.ViewName,
"base_table_id": &view.BaseTableID,
"base_table_name": &view.BaseTableName,
"include_all_columns": &view.IncludeAllColumns,
"where_clause": &view.WhereClause,
"bloom_filter_fp_chance": &view.Options.BloomFilterFpChance,
"caching": &view.Options.Caching,
"comment": &view.Options.Comment,
"compaction": &view.Options.Compaction,
"compression": &view.Options.Compression,
"crc_check_chance": &view.Options.CrcCheckChance,
"dclocal_read_repair_chance": &view.Options.DcLocalReadRepairChance,
"default_time_to_live": &view.Options.DefaultTimeToLive,
"gc_grace_seconds": &view.Options.GcGraceSeconds,
"max_index_interval": &view.Options.MaxIndexInterval,
"memtable_flush_period_in_ms": &view.Options.MemtableFlushPeriodInMs,
"min_index_interval": &view.Options.MinIndexInterval,
"read_repair_chance": &view.Options.ReadRepairChance,
"speculative_retry": &view.Options.SpeculativeRetry,
"extensions": &view.Extensions,
}) {
views = append(views, view)
view = ViewMetadata{KeyspaceName: keyspaceName}
}
err := iter.Close()
if err != nil && err != ErrNotFound {
return nil, fmt.Errorf("error querying view schema: %v", err)
}
return views, nil
}