From 5bb865442377b46048ed2db0271324cf0a4f268e Mon Sep 17 00:00:00 2001
From: Pavel Safonov <p.safonov@postgrespro.ru>
Date: Mon, 7 Nov 2022 12:05:33 +0300
Subject: [PATCH] postgres: remove lsn parameter in pg_wal

---
 format/format.go                              |  5 ----
 .../postgres/common/pg_wal/pgproee/decode.go  |  3 +--
 .../postgres/common/pg_wal/postgres/decode.go |  3 +--
 .../postgres/common/pg_wal/postgres/pg_wal.go | 14 +----------
 format/postgres/pg_wal.go                     | 25 ++++---------------
 5 files changed, 8 insertions(+), 42 deletions(-)

diff --git a/format/format.go b/format/format.go
index 79b9502e..b43caedf 100644
--- a/format/format.go
+++ b/format/format.go
@@ -333,8 +333,3 @@ type PostgresHeapIn struct {
 	PageNumber    int    `doc:"First page number in file, default is 0"`
 	SegmentNumber int    `doc:"Segment file number (16790.1 is 1), default is 0"`
 }
-
-type PostgresWalIn struct {
-	Flavour string `doc:"PostgreSQL flavour: postgres14, pgproee14.., postgres10"`
-	Lsn     string `doc:"Current LSN for WAL, use \"select pg_current_wal_lsn()\""`
-}
diff --git a/format/postgres/common/pg_wal/pgproee/decode.go b/format/postgres/common/pg_wal/pgproee/decode.go
index 98a46cb4..fe48c062 100644
--- a/format/postgres/common/pg_wal/pgproee/decode.go
+++ b/format/postgres/common/pg_wal/pgproee/decode.go
@@ -5,9 +5,8 @@ import (
 	"github.com/wader/fq/pkg/decode"
 )
 
-func DecodePGWAL(d *decode.D, maxOffset uint32) any {
+func DecodePGWAL(d *decode.D) any {
 	wal := &postgres.Wal{
-		MaxOffset:        int64(maxOffset),
 		DecodeXLogRecord: decodeXLogRecord,
 	}
 	return postgres.Decode(d, wal)
diff --git a/format/postgres/common/pg_wal/postgres/decode.go b/format/postgres/common/pg_wal/postgres/decode.go
index 2fe9b96f..0f899d6c 100644
--- a/format/postgres/common/pg_wal/postgres/decode.go
+++ b/format/postgres/common/pg_wal/postgres/decode.go
@@ -2,9 +2,8 @@ package postgres
 
 import "github.com/wader/fq/pkg/decode"
 
-func DecodePGWAL(d *decode.D, maxOffset uint32) any {
+func DecodePGWAL(d *decode.D) any {
 	wal := &Wal{
-		MaxOffset:        int64(maxOffset),
 		DecodeXLogRecord: decodeXLogRecord,
 	}
 	return Decode(d, wal)
diff --git a/format/postgres/common/pg_wal/postgres/pg_wal.go b/format/postgres/common/pg_wal/postgres/pg_wal.go
index 662f0b1c..22a57b97 100644
--- a/format/postgres/common/pg_wal/postgres/pg_wal.go
+++ b/format/postgres/common/pg_wal/postgres/pg_wal.go
@@ -49,8 +49,7 @@ const (
 /* total size (bytes):   12 */
 
 type Wal struct {
-	MaxOffset int64
-	page      *walPage
+	page *walPage
 
 	pageRecords *decode.D
 
@@ -79,11 +78,6 @@ func Decode(d *decode.D, wal *Wal) any {
 		}
 
 		posBytes := pages.Pos() / 8
-		if posBytes >= wal.MaxOffset {
-			d.FieldRawLen("unused", d.BitsLeft())
-			break
-		}
-
 		remBytes := posBytes % XLOG_BLCKSZ
 		if remBytes != 0 {
 			d.Fatalf("invalid page remBytes = %d\n", remBytes)
@@ -193,12 +187,6 @@ func decodeXLogRecords(wal *Wal, d *decode.D) {
 		/*   20      |     4 */ // pg_crc32c xl_crc
 		posBytes1 := d.Pos() / 8
 		posBytes1Aligned := int64(common.TypeAlign8(uint64(posBytes1)))
-		// check aligned - this is correct
-		// record header is 8 byte aligned
-		if posBytes1Aligned >= wal.MaxOffset {
-			d.FieldRawLen("unused", d.BitsLeft())
-			break
-		}
 
 		// check what we cat read xl_tot_len on this page
 		if posMaxOfPageBytes < posBytes1Aligned+4 {
diff --git a/format/postgres/pg_wal.go b/format/postgres/pg_wal.go
index 6e793223..7d72f3ed 100644
--- a/format/postgres/pg_wal.go
+++ b/format/postgres/pg_wal.go
@@ -21,9 +21,8 @@ func init() {
 		Name:        format.PG_WAL,
 		Description: "PostgreSQL write-ahead log file",
 		DecodeFn:    decodePGWAL,
-		DecodeInArg: format.PostgresWalIn{
+		DecodeInArg: format.PostgresIn{
 			Flavour: PG_FLAVOUR_POSTGRES14,
-			Lsn:     "",
 		},
 		RootArray: true,
 		RootName:  "pages",
@@ -48,28 +47,14 @@ func ParseLsn(lsn string) (uint32, error) {
 	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)
+	pgIn, ok := in.(format.PostgresIn)
 	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_POSTGRES10,
 		PG_FLAVOUR_POSTGRES11,
@@ -81,18 +66,18 @@ func decodePGWAL(d *decode.D, in any) any {
 		PG_FLAVOUR_PGPRO12,
 		PG_FLAVOUR_PGPRO13,
 		PG_FLAVOUR_PGPRO14:
-		return postgres.DecodePGWAL(d, maxOffset)
+		return postgres.DecodePGWAL(d)
 
 	case PG_FLAVOUR_PGPROEE10,
 		PG_FLAVOUR_PGPROEE11,
 		PG_FLAVOUR_PGPROEE12,
 		PG_FLAVOUR_PGPROEE13,
 		PG_FLAVOUR_PGPROEE14:
-		return pgproee.DecodePGWAL(d, maxOffset)
+		return pgproee.DecodePGWAL(d)
 
 	default:
 		break
 	}
 
-	return postgres.DecodePGWAL(d, maxOffset)
+	return postgres.DecodePGWAL(d)
 }