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mirror of https://github.com/wader/fq.git synced 2024-12-02 12:45:53 +03:00
fq/format/postgres/pg_wal.go
2022-09-23 13:50:54 +03:00

109 lines
2.3 KiB
Go

package postgres
import (
"fmt"
"github.com/wader/fq/format"
"github.com/wader/fq/format/postgres/flavours/postgres14"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"strconv"
"strings"
)
// TO DO
// not ready yet
func init() {
interp.RegisterFormat(decode.Format{
Name: format.PG_WAL,
Description: "PostgreSQL write-ahead log file",
DecodeFn: decodePgwal,
DecodeInArg: format.PostgresWalIn{
Flavour: PG_FLAVOUR_POSTGRES14,
Lsn: "",
},
})
}
// https://pgpedia.info/x/XLOG_PAGE_MAGIC.html
//nolint:revive
const (
XLOG_PAGE_MAGIC_15 = uint16(0xD10F)
XLOG_PAGE_MAGIC_14 = uint16(0xD10D)
XLOG_PAGE_MAGIC_13 = uint16(0xD106)
XLOG_PAGE_MAGIC_12 = uint16(0xD101)
XLOG_PAGE_MAGIC_11 = uint16(0xD098)
XLOG_PAGE_MAGIC_10 = uint16(0xD097)
XLOG_PAGE_MAGIC_96 = uint16(0xD093)
)
func ParseLsn(lsn string) (uint32, error) {
// check for 0/4E394440
str1 := lsn
if strings.Contains(lsn, "/") {
parts := strings.Split(lsn, "/")
if len(parts) != 2 {
return 0, fmt.Errorf("invalid lsn = %s", lsn)
}
str1 = parts[1]
}
// parse hex to coded file name + file offset
r1, err := strconv.ParseInt(str1, 16, 64)
if err != nil {
return 0, err
}
return uint32(r1), err
}
func XLogSegmentOffset(xLogPtr uint32) uint32 {
const walSegSizeBytes = 16 * 1024 * 1024
return xLogPtr & (walSegSizeBytes - 1)
}
func decodePgwal(d *decode.D, in any) any {
d.Endian = decode.LittleEndian
pgIn, ok := in.(format.PostgresWalIn)
if !ok {
d.Fatalf("DecodeInArg must be PostgresIn!\n")
}
maxOffset := uint32(0xFFFFFFFF)
if pgIn.Lsn != "" {
lsn, err := ParseLsn(pgIn.Lsn)
if err != nil {
d.Fatalf("Failed to ParseLsn, err = %v\n", err)
}
maxOffset = XLogSegmentOffset(lsn)
}
switch pgIn.Flavour {
//case PG_FLAVOUR_POSTGRES11:
// return postgres11.DecodePgControl(d, in)
case PG_FLAVOUR_POSTGRES14:
return postgres14.DecodePgwal(d, maxOffset)
//case PG_FLAVOUR_PGPROEE14:
// return pgproee14.DecodePgControl(d, in)
}
return probePgwal(d, maxOffset)
}
func probePgwal(d *decode.D, maxOffset uint32) any {
// read version
xlpMagic := uint16(d.U16())
// restore position
d.SeekAbs(0)
switch xlpMagic {
case XLOG_PAGE_MAGIC_14:
return postgres14.DecodePgwal(d, maxOffset)
}
d.Fatalf("unsupported xlp_magic = %X\n", xlpMagic)
return nil
}