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spgist_private.h
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1 /*-------------------------------------------------------------------------
2  *
3  * spgist_private.h
4  * Private declarations for SP-GiST access method.
5  *
6  *
7  * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
8  * Portions Copyright (c) 1994, Regents of the University of California
9  *
10  * src/include/access/spgist_private.h
11  *
12  *-------------------------------------------------------------------------
13  */
14 #ifndef SPGIST_PRIVATE_H
15 #define SPGIST_PRIVATE_H
16 
17 #include "access/itup.h"
18 #include "access/spgist.h"
19 #include "nodes/tidbitmap.h"
20 #include "storage/buf.h"
21 #include "utils/relcache.h"
22 
23 
24 /* Page numbers of fixed-location pages */
25 #define SPGIST_METAPAGE_BLKNO (0) /* metapage */
26 #define SPGIST_ROOT_BLKNO (1) /* root for normal entries */
27 #define SPGIST_NULL_BLKNO (2) /* root for null-value entries */
28 #define SPGIST_LAST_FIXED_BLKNO SPGIST_NULL_BLKNO
29 
30 #define SpGistBlockIsRoot(blkno) \
31  ((blkno) == SPGIST_ROOT_BLKNO || (blkno) == SPGIST_NULL_BLKNO)
32 #define SpGistBlockIsFixed(blkno) \
33  ((BlockNumber) (blkno) <= (BlockNumber) SPGIST_LAST_FIXED_BLKNO)
34 
35 /*
36  * Contents of page special space on SPGiST index pages
37  */
38 typedef struct SpGistPageOpaqueData
39 {
40  uint16 flags; /* see bit definitions below */
41  uint16 nRedirection; /* number of redirection tuples on page */
42  uint16 nPlaceholder; /* number of placeholder tuples on page */
43  /* note there's no count of either LIVE or DEAD tuples ... */
44  uint16 spgist_page_id; /* for identification of SP-GiST indexes */
46 
48 
49 /* Flag bits in page special space */
50 #define SPGIST_META (1<<0)
51 #define SPGIST_DELETED (1<<1) /* never set, but keep for backwards
52  * compatibility */
53 #define SPGIST_LEAF (1<<2)
54 #define SPGIST_NULLS (1<<3)
55 
56 #define SpGistPageGetOpaque(page) ((SpGistPageOpaque) PageGetSpecialPointer(page))
57 #define SpGistPageIsMeta(page) (SpGistPageGetOpaque(page)->flags & SPGIST_META)
58 #define SpGistPageIsDeleted(page) (SpGistPageGetOpaque(page)->flags & SPGIST_DELETED)
59 #define SpGistPageIsLeaf(page) (SpGistPageGetOpaque(page)->flags & SPGIST_LEAF)
60 #define SpGistPageStoresNulls(page) (SpGistPageGetOpaque(page)->flags & SPGIST_NULLS)
61 
62 /*
63  * The page ID is for the convenience of pg_filedump and similar utilities,
64  * which otherwise would have a hard time telling pages of different index
65  * types apart. It should be the last 2 bytes on the page. This is more or
66  * less "free" due to alignment considerations.
67  *
68  * See comments above GinPageOpaqueData.
69  */
70 #define SPGIST_PAGE_ID 0xFF82
71 
72 /*
73  * Each backend keeps a cache of last-used page info in its index->rd_amcache
74  * area. This is initialized from, and occasionally written back to,
75  * shared storage in the index metapage.
76  */
77 typedef struct SpGistLastUsedPage
78 {
79  BlockNumber blkno; /* block number, or InvalidBlockNumber */
80  int freeSpace; /* page's free space (could be obsolete!) */
82 
83 /* Note: indexes in cachedPage[] match flag assignments for SpGistGetBuffer */
84 #define SPGIST_CACHED_PAGES 8
85 
86 typedef struct SpGistLUPCache
87 {
90 
91 /*
92  * metapage
93  */
94 typedef struct SpGistMetaPageData
95 {
96  uint32 magicNumber; /* for identity cross-check */
97  SpGistLUPCache lastUsedPages; /* shared storage of last-used info */
99 
100 #define SPGIST_MAGIC_NUMBER (0xBA0BABEE)
101 
102 #define SpGistPageGetMeta(p) \
103  ((SpGistMetaPageData *) PageGetContents(p))
104 
105 /*
106  * Private state of index AM. SpGistState is common to both insert and
107  * search code; SpGistScanOpaque is for searches only.
108  */
109 
110 /* Per-datatype info needed in SpGistState */
111 typedef struct SpGistTypeDesc
112 {
114  bool attbyval;
117 
118 typedef struct SpGistState
119 {
120  spgConfigOut config; /* filled in by opclass config method */
121 
122  SpGistTypeDesc attType; /* type of values to be indexed/restored */
123  SpGistTypeDesc attLeafType; /* type of leaf-tuple values */
124  SpGistTypeDesc attPrefixType; /* type of inner-tuple prefix values */
125  SpGistTypeDesc attLabelType; /* type of node label values */
126 
127  char *deadTupleStorage; /* workspace for spgFormDeadTuple */
128 
129  TransactionId myXid; /* XID to use when creating a redirect tuple */
130  bool isBuild; /* true if doing index build */
131 } SpGistState;
132 
133 /*
134  * Private state of an index scan
135  */
136 typedef struct SpGistScanOpaqueData
137 {
138  SpGistState state; /* see above */
139  MemoryContext tempCxt; /* short-lived memory context */
140  MemoryContext traversalCxt; /* memory context for traversalValues */
141 
142  /* Control flags showing whether to search nulls and/or non-nulls */
143  bool searchNulls; /* scan matches (all) null entries */
144  bool searchNonNulls; /* scan matches (some) non-null entries */
145 
146  /* Index quals to be passed to opclass (null-related quals removed) */
147  int numberOfKeys; /* number of index qualifier conditions */
148  ScanKey keyData; /* array of index qualifier descriptors */
149 
150  /* Stack of yet-to-be-visited pages */
151  List *scanStack; /* List of ScanStackEntrys */
152 
153  /* These fields are only used in amgetbitmap scans: */
154  TIDBitmap *tbm; /* bitmap being filled */
155  int64 ntids; /* number of TIDs passed to bitmap */
156 
157  /* These fields are only used in amgettuple scans: */
158  bool want_itup; /* are we reconstructing tuples? */
159  TupleDesc indexTupDesc; /* if so, tuple descriptor for them */
160  int nPtrs; /* number of TIDs found on current page */
161  int iPtr; /* index for scanning through same */
162  ItemPointerData heapPtrs[MaxIndexTuplesPerPage]; /* TIDs from cur page */
163  bool recheck[MaxIndexTuplesPerPage]; /* their recheck flags */
164  HeapTuple reconTups[MaxIndexTuplesPerPage]; /* reconstructed tuples */
165 
166  /*
167  * Note: using MaxIndexTuplesPerPage above is a bit hokey since
168  * SpGistLeafTuples aren't exactly IndexTuples; however, they are larger,
169  * so this is safe.
170  */
172 
174 
175 /*
176  * This struct is what we actually keep in index->rd_amcache. It includes
177  * static configuration information as well as the lastUsedPages cache.
178  */
179 typedef struct SpGistCache
180 {
181  spgConfigOut config; /* filled in by opclass config method */
182 
183  SpGistTypeDesc attType; /* type of values to be indexed/restored */
184  SpGistTypeDesc attLeafType; /* type of leaf-tuple values */
185  SpGistTypeDesc attPrefixType; /* type of inner-tuple prefix values */
186  SpGistTypeDesc attLabelType; /* type of node label values */
187 
188  SpGistLUPCache lastUsedPages; /* local storage of last-used info */
189 } SpGistCache;
190 
191 
192 /*
193  * SPGiST tuple types. Note: inner, leaf, and dead tuple structs
194  * must have the same tupstate field in the same position! Real inner and
195  * leaf tuples always have tupstate = LIVE; if the state is something else,
196  * use the SpGistDeadTuple struct to inspect the tuple.
197  */
198 
199 /* values of tupstate (see README for more info) */
200 #define SPGIST_LIVE 0 /* normal live tuple (either inner or leaf) */
201 #define SPGIST_REDIRECT 1 /* temporary redirection placeholder */
202 #define SPGIST_DEAD 2 /* dead, cannot be removed because of links */
203 #define SPGIST_PLACEHOLDER 3 /* placeholder, used to preserve offsets */
204 
205 /*
206  * SPGiST inner tuple: list of "nodes" that subdivide a set of tuples
207  *
208  * Inner tuple layout:
209  * header/optional prefix/array of nodes, which are SpGistNodeTuples
210  *
211  * size and prefixSize must be multiples of MAXALIGN
212  */
213 typedef struct SpGistInnerTupleData
214 {
215  unsigned int tupstate:2, /* LIVE/REDIRECT/DEAD/PLACEHOLDER */
216  allTheSame:1, /* all nodes in tuple are equivalent */
217  nNodes:13, /* number of nodes within inner tuple */
218  prefixSize:16; /* size of prefix, or 0 if none */
219  uint16 size; /* total size of inner tuple */
220  /* On most machines there will be a couple of wasted bytes here */
221  /* prefix datum follows, then nodes */
223 
225 
226 /* these must match largest values that fit in bit fields declared above */
227 #define SGITMAXNNODES 0x1FFF
228 #define SGITMAXPREFIXSIZE 0xFFFF
229 #define SGITMAXSIZE 0xFFFF
230 
231 #define SGITHDRSZ MAXALIGN(sizeof(SpGistInnerTupleData))
232 #define _SGITDATA(x) (((char *) (x)) + SGITHDRSZ)
233 #define SGITDATAPTR(x) ((x)->prefixSize ? _SGITDATA(x) : NULL)
234 #define SGITDATUM(x, s) ((x)->prefixSize ? \
235  ((s)->attPrefixType.attbyval ? \
236  *(Datum *) _SGITDATA(x) : \
237  PointerGetDatum(_SGITDATA(x))) \
238  : (Datum) 0)
239 #define SGITNODEPTR(x) ((SpGistNodeTuple) (_SGITDATA(x) + (x)->prefixSize))
240 
241 /* Macro for iterating through the nodes of an inner tuple */
242 #define SGITITERATE(x, i, nt) \
243  for ((i) = 0, (nt) = SGITNODEPTR(x); \
244  (i) < (x)->nNodes; \
245  (i)++, (nt) = (SpGistNodeTuple) (((char *) (nt)) + IndexTupleSize(nt)))
246 
247 /*
248  * SPGiST node tuple: one node within an inner tuple
249  *
250  * Node tuples use the same header as ordinary Postgres IndexTuples, but
251  * we do not use a null bitmap, because we know there is only one column
252  * so the INDEX_NULL_MASK bit suffices. Also, pass-by-value datums are
253  * stored as a full Datum, the same convention as for inner tuple prefixes
254  * and leaf tuple datums.
255  */
256 
258 
260 
261 #define SGNTHDRSZ MAXALIGN(sizeof(SpGistNodeTupleData))
262 #define SGNTDATAPTR(x) (((char *) (x)) + SGNTHDRSZ)
263 #define SGNTDATUM(x, s) ((s)->attLabelType.attbyval ? \
264  *(Datum *) SGNTDATAPTR(x) : \
265  PointerGetDatum(SGNTDATAPTR(x)))
266 
267 /*
268  * SPGiST leaf tuple: carries a datum and a heap tuple TID
269  *
270  * In the simplest case, the datum is the same as the indexed value; but
271  * it could also be a suffix or some other sort of delta that permits
272  * reconstruction given knowledge of the prefix path traversed to get here.
273  *
274  * The size field is wider than could possibly be needed for an on-disk leaf
275  * tuple, but this allows us to form leaf tuples even when the datum is too
276  * wide to be stored immediately, and it costs nothing because of alignment
277  * considerations.
278  *
279  * Normally, nextOffset links to the next tuple belonging to the same parent
280  * node (which must be on the same page). But when the root page is a leaf
281  * page, we don't chain its tuples, so nextOffset is always 0 on the root.
282  *
283  * size must be a multiple of MAXALIGN; also, it must be at least SGDTSIZE
284  * so that the tuple can be converted to REDIRECT status later. (This
285  * restriction only adds bytes for the null-datum case, otherwise alignment
286  * restrictions force it anyway.)
287  *
288  * In a leaf tuple for a NULL indexed value, there's no useful datum value;
289  * however, the SGDTSIZE limit ensures that's there's a Datum word there
290  * anyway, so SGLTDATUM can be applied safely as long as you don't do
291  * anything with the result.
292  */
293 typedef struct SpGistLeafTupleData
294 {
295  unsigned int tupstate:2, /* LIVE/REDIRECT/DEAD/PLACEHOLDER */
296  size:30; /* large enough for any palloc'able value */
297  OffsetNumber nextOffset; /* next tuple in chain, or InvalidOffset */
298  ItemPointerData heapPtr; /* TID of represented heap tuple */
299  /* leaf datum follows */
301 
303 
304 #define SGLTHDRSZ MAXALIGN(sizeof(SpGistLeafTupleData))
305 #define SGLTDATAPTR(x) (((char *) (x)) + SGLTHDRSZ)
306 #define SGLTDATUM(x, s) ((s)->attLeafType.attbyval ? \
307  *(Datum *) SGLTDATAPTR(x) : \
308  PointerGetDatum(SGLTDATAPTR(x)))
309 
310 /*
311  * SPGiST dead tuple: declaration for examining non-live tuples
312  *
313  * The tupstate field of this struct must match those of regular inner and
314  * leaf tuples, and its size field must match a leaf tuple's.
315  * Also, the pointer field must be in the same place as a leaf tuple's heapPtr
316  * field, to satisfy some Asserts that we make when replacing a leaf tuple
317  * with a dead tuple.
318  * We don't use nextOffset, but it's needed to align the pointer field.
319  * pointer and xid are only valid when tupstate = REDIRECT.
320  */
321 typedef struct SpGistDeadTupleData
322 {
323  unsigned int tupstate:2, /* LIVE/REDIRECT/DEAD/PLACEHOLDER */
324  size:30;
325  OffsetNumber nextOffset; /* not used in dead tuples */
326  ItemPointerData pointer; /* redirection inside index */
327  TransactionId xid; /* ID of xact that inserted this tuple */
329 
331 
332 #define SGDTSIZE MAXALIGN(sizeof(SpGistDeadTupleData))
333 
334 /*
335  * Macros for doing free-space calculations. Note that when adding up the
336  * space needed for tuples, we always consider each tuple to need the tuple's
337  * size plus sizeof(ItemIdData) (for the line pointer). This works correctly
338  * so long as tuple sizes are always maxaligned.
339  */
340 
341 /* Page capacity after allowing for fixed header and special space */
342 #define SPGIST_PAGE_CAPACITY \
343  MAXALIGN_DOWN(BLCKSZ - \
344  SizeOfPageHeaderData - \
345  MAXALIGN(sizeof(SpGistPageOpaqueData)))
346 
347 /*
348  * Compute free space on page, assuming that up to n placeholders can be
349  * recycled if present (n should be the number of tuples to be inserted)
350  */
351 #define SpGistPageGetFreeSpace(p, n) \
352  (PageGetExactFreeSpace(p) + \
353  Min(SpGistPageGetOpaque(p)->nPlaceholder, n) * \
354  (SGDTSIZE + sizeof(ItemIdData)))
355 
356 /*
357  * XLOG stuff
358  */
359 
360 #define STORE_STATE(s, d) \
361  do { \
362  (d).myXid = (s)->myXid; \
363  (d).isBuild = (s)->isBuild; \
364  } while(0)
365 
366 /*
367  * The "flags" argument for SpGistGetBuffer should be either GBUF_LEAF to
368  * get a leaf page, or GBUF_INNER_PARITY(blockNumber) to get an inner
369  * page in the same triple-parity group as the specified block number.
370  * (Typically, this should be GBUF_INNER_PARITY(parentBlockNumber + 1)
371  * to follow the rule described in spgist/README.)
372  * In addition, GBUF_NULLS can be OR'd in to get a page for storage of
373  * null-valued tuples.
374  *
375  * Note: these flag values are used as indexes into lastUsedPages.
376  */
377 #define GBUF_LEAF 0x03
378 #define GBUF_INNER_PARITY(x) ((x) % 3)
379 #define GBUF_NULLS 0x04
380 
381 #define GBUF_PARITY_MASK 0x03
382 #define GBUF_REQ_LEAF(flags) (((flags) & GBUF_PARITY_MASK) == GBUF_LEAF)
383 #define GBUF_REQ_NULLS(flags) ((flags) & GBUF_NULLS)
384 
385 /* spgutils.c */
389 extern void SpGistUpdateMetaPage(Relation index);
391  int needSpace, bool *isNew);
393 extern void SpGistInitPage(Page page, uint16 f);
394 extern void SpGistInitBuffer(Buffer b, uint16 f);
395 extern void SpGistInitMetapage(Page page);
396 extern unsigned int SpGistGetTypeSize(SpGistTypeDesc *att, Datum datum);
398  ItemPointer heapPtr,
399  Datum datum, bool isnull);
401  Datum label, bool isnull);
403  bool hasPrefix, Datum prefix,
404  int nNodes, SpGistNodeTuple *nodes);
405 extern SpGistDeadTuple spgFormDeadTuple(SpGistState *state, int tupstate,
406  BlockNumber blkno, OffsetNumber offnum);
408  SpGistInnerTuple innerTuple);
410  Item item, Size size,
411  OffsetNumber *startOffset,
412  bool errorOK);
413 
414 /* spgdoinsert.c */
415 extern void spgUpdateNodeLink(SpGistInnerTuple tup, int nodeN,
416  BlockNumber blkno, OffsetNumber offset);
417 extern void spgPageIndexMultiDelete(SpGistState *state, Page page,
418  OffsetNumber *itemnos, int nitems,
419  int firststate, int reststate,
420  BlockNumber blkno, OffsetNumber offnum);
422  ItemPointer heapPtr, Datum datum, bool isnull);
423 
424 #endif /* SPGIST_PRIVATE_H */
signed short int16
Definition: c.h:312
SpGistLeafTuple spgFormLeafTuple(SpGistState *state, ItemPointer heapPtr, Datum datum, bool isnull)
Definition: spgutils.c:630
SpGistTypeDesc attLeafType
SpGistCache * spgGetCache(Relation index)
Definition: spgutils.c:93
SpGistPageOpaqueData * SpGistPageOpaque
SpGistTypeDesc attPrefixType
SpGistInnerTupleData * SpGistInnerTuple
uint32 TransactionId
Definition: c.h:474
void initSpGistState(SpGistState *state, Relation index)
Definition: spgutils.c:175
SpGistNodeTuple spgFormNodeTuple(SpGistState *state, Datum label, bool isnull)
Definition: spgutils.c:667
void SpGistInitPage(Page page, uint16 f)
Definition: spgutils.c:529
SpGistTypeDesc attLeafType
struct SpGistPageOpaqueData SpGistPageOpaqueData
SpGistTypeDesc attType
Datum * spgExtractNodeLabels(SpGistState *state, SpGistInnerTuple innerTuple)
Definition: spgutils.c:822
Pointer Item
Definition: item.h:17
MemoryContext tempCxt
uint32 BlockNumber
Definition: block.h:31
SpGistTypeDesc attLabelType
IndexTupleData SpGistNodeTupleData
unsigned int Oid
Definition: postgres_ext.h:31
struct SpGistDeadTupleData SpGistDeadTupleData
SpGistTypeDesc attType
bool spgdoinsert(Relation index, SpGistState *state, ItemPointer heapPtr, Datum datum, bool isnull)
Definition: spgdoinsert.c:1891
struct SpGistLeafTupleData SpGistLeafTupleData
SpGistLUPCache lastUsedPages
uint16 OffsetNumber
Definition: off.h:24
Definition: type.h:89
spgConfigOut config
unsigned short uint16
Definition: c.h:324
ItemPointerData pointer
struct SpGistLastUsedPage SpGistLastUsedPage
struct SpGistTypeDesc SpGistTypeDesc
void spgUpdateNodeLink(SpGistInnerTuple tup, int nodeN, BlockNumber blkno, OffsetNumber offset)
Definition: spgdoinsert.c:50
struct SpGistMetaPageData SpGistMetaPageData
Buffer SpGistNewBuffer(Relation index)
Definition: spgutils.c:205
unsigned int SpGistGetTypeSize(SpGistTypeDesc *att, Datum datum)
Definition: spgutils.c:593
SpGistDeadTupleData * SpGistDeadTuple
struct SpGistLUPCache SpGistLUPCache
unsigned int uint32
Definition: c.h:325
TransactionId myXid
Buffer SpGistGetBuffer(Relation index, int flags, int needSpace, bool *isNew)
Definition: spgutils.c:389
void spgPageIndexMultiDelete(SpGistState *state, Page page, OffsetNumber *itemnos, int nitems, int firststate, int reststate, BlockNumber blkno, OffsetNumber offnum)
Definition: spgdoinsert.c:131
SpGistDeadTuple spgFormDeadTuple(SpGistState *state, int tupstate, BlockNumber blkno, OffsetNumber offnum)
Definition: spgutils.c:792
SpGistInnerTuple spgFormInnerTuple(SpGistState *state, bool hasPrefix, Datum prefix, int nNodes, SpGistNodeTuple *nodes)
Definition: spgutils.c:709
void SpGistSetLastUsedPage(Relation index, Buffer buffer)
Definition: spgutils.c:494
spgConfigOut config
unsigned int tupstate
SpGistLUPCache lastUsedPages
OffsetNumber SpGistPageAddNewItem(SpGistState *state, Page page, Item item, Size size, OffsetNumber *startOffset, bool errorOK)
Definition: spgutils.c:865
unsigned int tupstate
uintptr_t Datum
Definition: postgres.h:367
void SpGistUpdateMetaPage(Relation index)
Definition: spgutils.c:270
static char * label
Definition: pg_basebackup.c:84
char * deadTupleStorage
SpGistScanOpaqueData * SpGistScanOpaque
OffsetNumber nextOffset
void SpGistInitBuffer(Buffer b, uint16 f)
Definition: spgutils.c:544
Definition: regguts.h:298
WalTimeSample buffer[LAG_TRACKER_BUFFER_SIZE]
Definition: walsender.c:215
size_t Size
Definition: c.h:433
OffsetNumber nextOffset
#define SPGIST_CACHED_PAGES
SpGistTypeDesc attLabelType
MemoryContext traversalCxt
struct SpGistCache SpGistCache
#define MaxIndexTuplesPerPage
Definition: itup.h:145
void SpGistInitMetapage(Page page)
Definition: spgutils.c:554
SpGistTypeDesc attPrefixType
ItemPointerData heapPtr
struct SpGistInnerTupleData SpGistInnerTupleData
SpGistLeafTupleData * SpGistLeafTuple
struct SpGistScanOpaqueData SpGistScanOpaqueData
Definition: pg_list.h:45
int Buffer
Definition: buf.h:23
struct SpGistState SpGistState
Pointer Page
Definition: bufpage.h:74
SpGistNodeTupleData * SpGistNodeTuple