Split index xlog headers from other private index headers.

The xlog-specific headers need to be included in both frontend code -
specifically, pg_waldump - and the backend, but the remainder of the
private headers for each index are only needed by the backend.  By
splitting the xlog stuff out into separate headers, pg_waldump pulls
in fewer backend headers, which is a good thing.

Patch by me, reviewed by Michael Paquier and Andres Freund, per a
complaint from Dilip Kumar.

Discussion: http://postgr.es/m/CA+TgmoZ=F=GkxV0YEv-A8tb+AEGy_Qa7GSiJ8deBKFATnzfEug@mail.gmail.com

src/include/access/ginxlog.h

@@ -0,0 +1,217 @@
+/*--------------------------------------------------------------------------
+ * ginxlog.h
+ *	  header file for postgres inverted index xlog implementation.
+ *
+ *	Copyright (c) 2006-2017, PostgreSQL Global Development Group
+ *
+ *	src/include/access/ginxlog.h
+ *--------------------------------------------------------------------------
+ */
+#ifndef GINXLOG_H
+#define GINXLOG_H
+
+#include "access/ginblock.h"
+#include "access/itup.h"
+#include "access/xlogreader.h"
+#include "lib/stringinfo.h"
+#include "storage/off.h"
+
+#define XLOG_GIN_CREATE_INDEX  0x00
+
+#define XLOG_GIN_CREATE_PTREE  0x10
+
+typedef struct ginxlogCreatePostingTree
+{
+	uint32		size;
+	/* A compressed posting list follows */
+} ginxlogCreatePostingTree;
+
+/*
+ * The format of the insertion record varies depending on the page type.
+ * ginxlogInsert is the common part between all variants.
+ *
+ * Backup Blk 0: target page
+ * Backup Blk 1: left child, if this insertion finishes an incomplete split
+ */
+
+#define XLOG_GIN_INSERT  0x20
+
+typedef struct
+{
+	uint16		flags;			/* GIN_INSERT_ISLEAF and/or GIN_INSERT_ISDATA */
+
+	/*
+	 * FOLLOWS:
+	 *
+	 * 1. if not leaf page, block numbers of the left and right child pages
+	 * whose split this insertion finishes, as BlockIdData[2] (beware of
+	 * adding fields in this struct that would make them not 16-bit aligned)
+	 *
+	 * 2. a ginxlogInsertEntry or ginxlogRecompressDataLeaf struct, depending
+	 * on tree type.
+	 *
+	 * NB: the below structs are only 16-bit aligned when appended to a
+	 * ginxlogInsert struct! Beware of adding fields to them that require
+	 * stricter alignment.
+	 */
+} ginxlogInsert;
+
+typedef struct
+{
+	OffsetNumber offset;
+	bool		isDelete;
+	IndexTupleData tuple;		/* variable length */
+} ginxlogInsertEntry;
+
+
+typedef struct
+{
+	uint16		nactions;
+
+	/* Variable number of 'actions' follow */
+} ginxlogRecompressDataLeaf;
+
+/*
+ * Note: this struct is currently not used in code, and only acts as
+ * documentation. The WAL record format is as specified here, but the code
+ * uses straight access through a Pointer and memcpy to read/write these.
+ */
+typedef struct
+{
+	uint8		segno;			/* segment this action applies to */
+	char		type;			/* action type (see below) */
+
+	/*
+	 * Action-specific data follows. For INSERT and REPLACE actions that is a
+	 * GinPostingList struct. For ADDITEMS, a uint16 for the number of items
+	 * added, followed by the items themselves as ItemPointers. DELETE actions
+	 * have no further data.
+	 */
+}	ginxlogSegmentAction;
+
+/* Action types */
+#define GIN_SEGMENT_UNMODIFIED	0		/* no action (not used in WAL records) */
+#define GIN_SEGMENT_DELETE		1		/* a whole segment is removed */
+#define GIN_SEGMENT_INSERT		2		/* a whole segment is added */
+#define GIN_SEGMENT_REPLACE		3		/* a segment is replaced */
+#define GIN_SEGMENT_ADDITEMS	4		/* items are added to existing segment */
+
+typedef struct
+{
+	OffsetNumber offset;
+	PostingItem newitem;
+} ginxlogInsertDataInternal;
+
+/*
+ * Backup Blk 0: new left page (= original page, if not root split)
+ * Backup Blk 1: new right page
+ * Backup Blk 2: original page / new root page, if root split
+ * Backup Blk 3: left child, if this insertion completes an earlier split
+ */
+#define XLOG_GIN_SPLIT	0x30
+
+typedef struct ginxlogSplit
+{
+	RelFileNode node;
+	BlockNumber rrlink;			/* right link, or root's blocknumber if root
+								 * split */
+	BlockNumber leftChildBlkno; /* valid on a non-leaf split */
+	BlockNumber rightChildBlkno;
+	uint16		flags;			/* see below */
+} ginxlogSplit;
+
+/*
+ * Flags used in ginxlogInsert and ginxlogSplit records
+ */
+#define GIN_INSERT_ISDATA	0x01	/* for both insert and split records */
+#define GIN_INSERT_ISLEAF	0x02	/* ditto */
+#define GIN_SPLIT_ROOT		0x04	/* only for split records */
+
+/*
+ * Vacuum simply WAL-logs the whole page, when anything is modified. This
+ * is functionally identical to heap_newpage records, but is kept separate for
+ * debugging purposes. (When inspecting the WAL stream, it's easier to see
+ * what's going on when GIN vacuum records are marked as such, not as heap
+ * records.) This is currently only used for entry tree leaf pages.
+ */
+#define XLOG_GIN_VACUUM_PAGE	0x40
+
+/*
+ * Vacuuming posting tree leaf page is WAL-logged like recompression caused
+ * by insertion.
+ */
+#define XLOG_GIN_VACUUM_DATA_LEAF_PAGE	0x90
+
+typedef struct ginxlogVacuumDataLeafPage
+{
+	ginxlogRecompressDataLeaf data;
+} ginxlogVacuumDataLeafPage;
+
+/*
+ * Backup Blk 0: deleted page
+ * Backup Blk 1: parent
+ * Backup Blk 2: left sibling
+ */
+#define XLOG_GIN_DELETE_PAGE	0x50
+
+typedef struct ginxlogDeletePage
+{
+	OffsetNumber parentOffset;
+	BlockNumber rightLink;
+} ginxlogDeletePage;
+
+#define XLOG_GIN_UPDATE_META_PAGE 0x60
+
+/*
+ * Backup Blk 0: metapage
+ * Backup Blk 1: tail page
+ */
+typedef struct ginxlogUpdateMeta
+{
+	RelFileNode node;
+	GinMetaPageData metadata;
+	BlockNumber prevTail;
+	BlockNumber newRightlink;
+	int32		ntuples;		/* if ntuples > 0 then metadata.tail was
+								 * updated with that many tuples; else new sub
+								 * list was inserted */
+	/* array of inserted tuples follows */
+} ginxlogUpdateMeta;
+
+#define XLOG_GIN_INSERT_LISTPAGE  0x70
+
+typedef struct ginxlogInsertListPage
+{
+	BlockNumber rightlink;
+	int32		ntuples;
+	/* array of inserted tuples follows */
+} ginxlogInsertListPage;
+
+/*
+ * Backup Blk 0: metapage
+ * Backup Blk 1 to (ndeleted + 1): deleted pages
+ */
+
+#define XLOG_GIN_DELETE_LISTPAGE  0x80
+
+/*
+ * The WAL record for deleting list pages must contain a block reference to
+ * all the deleted pages, so the number of pages that can be deleted in one
+ * record is limited by XLR_MAX_BLOCK_ID. (block_id 0 is used for the
+ * metapage.)
+ */
+#define GIN_NDELETE_AT_ONCE Min(16, XLR_MAX_BLOCK_ID - 1)
+typedef struct ginxlogDeleteListPages
+{
+	GinMetaPageData metadata;
+	int32		ndeleted;
+} ginxlogDeleteListPages;
+
+extern void gin_redo(XLogReaderState *record);
+extern void gin_desc(StringInfo buf, XLogReaderState *record);
+extern const char *gin_identify(uint8 info);
+extern void gin_xlog_startup(void);
+extern void gin_xlog_cleanup(void);
+extern void gin_mask(char *pagedata, BlockNumber blkno);
+
+#endif   /* GINXLOG_H */