postgres: pg_btree begin impl

format/format.go

@@ -103,6 +103,7 @@ const (
 	OPUS_PACKET         = "opus_packet"
 	PCAP                = "pcap"
 	PCAPNG              = "pcapng"
+	PG_BTREE            = "pg_btree"
 	PG_WAL              = "pg_wal"
 	PG_WALPAGE          = "pg_wal_page"
 	PG_MULTIXACTOFF     = "pg_multixact_offsets"

format/postgres/flavours/postgres14/pg_btree.go

@@ -0,0 +1,146 @@
+package postgres14
+
+import (
+	"github.com/wader/fq/format/postgres/common"
+	"github.com/wader/fq/pkg/decode"
+)
+
+const (
+	BTREE_MAGIC = 0x053162
+)
+
+// struct BTMetaPageData {
+/*    0      |     4 */ // uint32 btm_magic
+/*    4      |     4 */ // uint32 btm_version
+/*    8      |     4 */ // BlockNumber btm_root
+/*   12      |     4 */ // uint32 btm_level
+/*   16      |     4 */ // BlockNumber btm_fastroot
+/*   20      |     4 */ // uint32 btm_fastlevel
+/*   24      |     4 */ // uint32 btm_last_cleanup_num_delpages
+/* XXX  4-byte hole */
+/*   32      |     8 */ // float8 btm_last_cleanup_num_heap_tuples
+/*   40      |     1 */ // _Bool btm_allequalimage
+/* XXX  7-byte padding */
+//
+/* total size (bytes):   48 */
+
+func DecodePgBTree(d *decode.D) any {
+	d.SeekAbs(0)
+
+	btree := &BTreeD{
+		PageSize: common.HeapPageSize,
+	}
+	decodeBTreePages(btree, d)
+
+	return nil
+}
+
+type BTreeD struct {
+	PageSize uint64
+	page     *BTreePage
+}
+
+type BTreePage struct {
+	heap            HeapPage
+	bytesPosBegin   uint64 // bytes pos of page's beginning
+	bytesPosEnd     uint64 // bytes pos of page's ending
+	bytesPosSpecial uint64 // bytes pos of page's special
+}
+
+type HeapPage struct {
+	PdLower           uint16
+	PdUpper           uint16
+	PdSpecial         uint16
+	PdPagesizeVersion uint16
+}
+
+func decodeBTreePages(btree *BTreeD, d *decode.D) {
+	for i := 0; ; i++ {
+		if end, _ := d.TryEnd(); end {
+			return
+		}
+
+		page := &BTreePage{}
+		if btree.page != nil {
+			// use prev page
+			page.bytesPosBegin = btree.page.bytesPosEnd
+		}
+		page.bytesPosEnd = common.TypeAlign(btree.PageSize, page.bytesPosBegin+1)
+		btree.page = page
+
+		if i == 0 {
+			// first page contains meta information
+			d.FieldStruct("heap_page", func(d *decode.D) {
+				decodeBTreeMetaPage(btree, d)
+			})
+			continue
+		}
+
+		if i > 0 {
+			return
+		}
+	}
+}
+
+func decodeBTreeMetaPage(btree *BTreeD, d *decode.D) {
+	d.FieldStruct("page_header", func(d *decode.D) {
+		decodePageHeader(btree, d)
+	})
+	d.FieldStruct("meta_page_data", func(d *decode.D) {
+		decodeBTMetaPageData(btree, d)
+	})
+}
+
+func decodePageHeader(btree *BTreeD, d *decode.D) {
+	heap := btree.page.heap
+
+	d.FieldStruct("pd_lsn", func(d *decode.D) {
+		/*    0      |     4 */ // uint32 xlogid;
+		/*    4      |     4 */ // uint32 xrecoff;
+		d.FieldU32("xlogid", common.HexMapper)
+		d.FieldU32("xrecoff", common.HexMapper)
+	})
+	d.FieldU16("pd_checksum")
+	d.FieldU16("pd_flags")
+	heap.PdLower = uint16(d.FieldU16("pd_lower"))
+	heap.PdUpper = uint16(d.FieldU16("pd_upper"))
+	heap.PdSpecial = uint16(d.FieldU16("pd_special"))
+	heap.PdPagesizeVersion = uint16(d.FieldU16("pd_pagesize_version"))
+	d.FieldU32("pd_prune_xid")
+
+	// ItemIdData pd_linp[];
+	//page.ItemsEnd = int64(page.PagePosBegin*8) + int64(page.PdLower*8)
+	//d.FieldArray("pd_linp", func(d *decode.D) {
+	//	DecodeItemIds(heap, d)
+	//})
+}
+
+func decodeBTMetaPageData(btree *BTreeD, d *decode.D) {
+	/*    0      |     4 */ // uint32 btm_magic
+	/*    4      |     4 */ // uint32 btm_version
+	/*    8      |     4 */ // BlockNumber btm_root
+	/*   12      |     4 */ // uint32 btm_level
+	/*   16      |     4 */ // BlockNumber btm_fastroot
+	/*   20      |     4 */ // uint32 btm_fastlevel
+	/*   24      |     4 */ // uint32 btm_last_cleanup_num_delpages
+	/* XXX  4-byte hole */
+	/*   32      |     8 */ // float8 btm_last_cleanup_num_heap_tuples
+	/*   40      |     1 */ // _Bool btm_allequalimage
+	/* XXX  7-byte padding */
+
+	btmMagic := d.FieldU32("btm_magic")
+	d.FieldU32("btm_version")
+	d.FieldU32("btm_root")
+	d.FieldU32("btm_level")
+	d.FieldU32("btm_fastroot")
+	d.FieldU32("btm_fastlevel")
+	d.FieldU32("btm_last_cleanup_num_delpages")
+	d.FieldU32("hole0")
+	d.FieldF64("btm_last_cleanup_num_heap_tuples")
+	d.FieldU8("btm_allequalimage")
+	d.FieldU56("padding0")
+
+	if btmMagic != BTREE_MAGIC {
+		d.Fatalf("invalid btmMagic = %X, must be %X\n", btmMagic, BTREE_MAGIC)
+	}
+}

format/postgres/pg_btree.go

@@ -0,0 +1,37 @@
+package postgres
+
+import (
+	"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"
+)
+
+func init() {
+	interp.RegisterFormat(decode.Format{
+		Name:        format.PG_BTREE,
+		Description: "PostgreSQL btree index file",
+		DecodeFn:    decodePgBTree,
+		DecodeInArg: format.PostgresIn{
+			Flavour: "default",
+		},
+		RootArray: true,
+		RootName:  "pages",
+	})
+}
+
+func decodePgBTree(d *decode.D, in any) any {
+	d.Endian = decode.LittleEndian
+
+	pgIn, ok := in.(format.PostgresIn)
+	if !ok {
+		d.Fatalf("DecodeInArg must be PostgresIn!\n")
+	}
+
+	switch pgIn.Flavour {
+	case PG_FLAVOUR_POSTGRES14, PG_FLAVOUR_POSTGRES:
+		return postgres14.DecodePgBTree(d)
+	}
+
+	return nil
+}