mapserver/db/sqlite.go
2019-01-09 16:31:24 +01:00

118 lines
2.4 KiB
Go

package db
import (
"database/sql"
_ "github.com/mattn/go-sqlite3"
"github.com/sirupsen/logrus"
"mapserver/coords"
"time"
)
var log *logrus.Entry
func init(){
log = logrus.WithFields(logrus.Fields{"prefix": "db/sqlite"})
}
const migrateScript = `
alter table blocks add mtime integer default 0;
create index blocks_mtime on blocks(mtime);
CREATE TRIGGER update_blocks_mtime_insert after insert on blocks for each row
begin
update blocks set mtime = strftime('%s', 'now') where pos = new.pos;
end;
CREATE TRIGGER update_blocks_mtime_update after update on blocks for each row
begin
update blocks set mtime = strftime('%s', 'now') where pos = old.pos;
end;
`
//TODO: initial run: https://stackoverflow.com/questions/14468586/efficient-paging-in-sqlite-with-millions-of-records
//TODO: postgres test
type Sqlite3Accessor struct {
db *sql.DB
filename string
}
func (db *Sqlite3Accessor) Migrate() error {
//RW connection
rwdb, err := sql.Open("sqlite3", db.filename + "?mode=rw")
if err != nil {
return err
}
defer rwdb.Close()
hasMtime := true
_, err = rwdb.Query("select max(mtime) from blocks")
if err != nil {
hasMtime = false
}
if !hasMtime {
log.WithFields(logrus.Fields{"filename":db.filename}).Info("Migrating database")
start := time.Now()
_, err = rwdb.Exec(migrateScript)
if err != nil {
return err
}
t := time.Now()
elapsed := t.Sub(start)
log.WithFields(logrus.Fields{"elapsed":elapsed}).Info("Migration completed")
}
return nil
}
func convertRows(pos int64, data []byte, mtime int64) Block {
c := coords.PlainToCoord(pos)
return Block{Pos:c, Data:data, Mtime:mtime}
}
func (db *Sqlite3Accessor) FindLatestBlocks(mintime int64, limit int) ([]Block, error) {
return make([]Block, 0), nil
}
const getBlockQuery = `
select pos,data,mtime from blocks b where b.pos = ?
`
func (db *Sqlite3Accessor) GetBlock(pos coords.MapBlockCoords) (*Block, error) {
ppos := coords.CoordToPlain(pos)
rows, err := db.db.Query(getBlockQuery, ppos)
if err != nil {
return nil, err
}
if rows.Next() {
var pos int64
var data []byte
var mtime int64
err = rows.Scan(&pos, &data, &mtime)
if err != nil {
return nil, err
}
mb := convertRows(pos, data, mtime)
return &mb, nil
}
return nil, nil
}
func NewSqliteAccessor(filename string) (*Sqlite3Accessor, error) {
db, err := sql.Open("sqlite3", filename + "?mode=ro")
if err != nil {
return nil, err
}
sq := &Sqlite3Accessor{db: db, filename: filename}
return sq, nil
}