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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * nbtree.h
4 : : * header file for postgres btree access method implementation.
5 : : *
6 : : *
7 : : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
8 : : * Portions Copyright (c) 1994, Regents of the University of California
9 : : *
10 : : * src/include/access/nbtree.h
11 : : *
12 : : *-------------------------------------------------------------------------
13 : : */
14 : : #ifndef NBTREE_H
15 : : #define NBTREE_H
16 : :
17 : : #include "access/amapi.h"
18 : : #include "access/itup.h"
19 : : #include "access/sdir.h"
20 : : #include "catalog/pg_am_d.h"
21 : : #include "catalog/pg_class.h"
22 : : #include "catalog/pg_index.h"
23 : : #include "lib/stringinfo.h"
24 : : #include "storage/bufmgr.h"
25 : : #include "storage/dsm.h"
26 : : #include "storage/shm_toc.h"
27 : : #include "utils/skipsupport.h"
28 : :
29 : : /* There's room for a 16-bit vacuum cycle ID in BTPageOpaqueData */
30 : : typedef uint16 BTCycleId;
31 : :
32 : : /*
33 : : * BTPageOpaqueData -- At the end of every page, we store a pointer
34 : : * to both siblings in the tree. This is used to do forward/backward
35 : : * index scans. The next-page link is also critical for recovery when
36 : : * a search has navigated to the wrong page due to concurrent page splits
37 : : * or deletions; see src/backend/access/nbtree/README for more info.
38 : : *
39 : : * In addition, we store the page's btree level (counting upwards from
40 : : * zero at a leaf page) as well as some flag bits indicating the page type
41 : : * and status. If the page is deleted, a BTDeletedPageData struct is stored
42 : : * in the page's tuple area, while a standard BTPageOpaqueData struct is
43 : : * stored in the page special area.
44 : : *
45 : : * We also store a "vacuum cycle ID". When a page is split while VACUUM is
46 : : * processing the index, a nonzero value associated with the VACUUM run is
47 : : * stored into both halves of the split page. (If VACUUM is not running,
48 : : * both pages receive zero cycleids.) This allows VACUUM to detect whether
49 : : * a page was split since it started, with a small probability of false match
50 : : * if the page was last split some exact multiple of MAX_BT_CYCLE_ID VACUUMs
51 : : * ago. Also, during a split, the BTP_SPLIT_END flag is cleared in the left
52 : : * (original) page, and set in the right page, but only if the next page
53 : : * to its right has a different cycleid.
54 : : *
55 : : * NOTE: the BTP_LEAF flag bit is redundant since level==0 could be tested
56 : : * instead.
57 : : *
58 : : * NOTE: the btpo_level field used to be a union type in order to allow
59 : : * deleted pages to store a 32-bit safexid in the same field. We now store
60 : : * 64-bit/full safexid values using BTDeletedPageData instead.
61 : : */
62 : :
63 : : typedef struct BTPageOpaqueData
64 : : {
65 : : BlockNumber btpo_prev; /* left sibling, or P_NONE if leftmost */
66 : : BlockNumber btpo_next; /* right sibling, or P_NONE if rightmost */
67 : : uint32 btpo_level; /* tree level --- zero for leaf pages */
68 : : uint16 btpo_flags; /* flag bits, see below */
69 : : BTCycleId btpo_cycleid; /* vacuum cycle ID of latest split */
70 : : } BTPageOpaqueData;
71 : :
72 : : typedef BTPageOpaqueData *BTPageOpaque;
73 : :
74 : : #define BTPageGetOpaque(page) ((BTPageOpaque) PageGetSpecialPointer(page))
75 : :
76 : : /* Bits defined in btpo_flags */
77 : : #define BTP_LEAF (1 << 0) /* leaf page, i.e. not internal page */
78 : : #define BTP_ROOT (1 << 1) /* root page (has no parent) */
79 : : #define BTP_DELETED (1 << 2) /* page has been deleted from tree */
80 : : #define BTP_META (1 << 3) /* meta-page */
81 : : #define BTP_HALF_DEAD (1 << 4) /* empty, but still in tree */
82 : : #define BTP_SPLIT_END (1 << 5) /* rightmost page of split group */
83 : : #define BTP_HAS_GARBAGE (1 << 6) /* page has LP_DEAD tuples (deprecated) */
84 : : #define BTP_INCOMPLETE_SPLIT (1 << 7) /* right sibling's downlink is missing */
85 : : #define BTP_HAS_FULLXID (1 << 8) /* contains BTDeletedPageData */
86 : :
87 : : /*
88 : : * The max allowed value of a cycle ID is a bit less than 64K. This is
89 : : * for convenience of pg_filedump and similar utilities: we want to use
90 : : * the last 2 bytes of special space as an index type indicator, and
91 : : * restricting cycle ID lets btree use that space for vacuum cycle IDs
92 : : * while still allowing index type to be identified.
93 : : */
94 : : #define MAX_BT_CYCLE_ID 0xFF7F
95 : :
96 : :
97 : : /*
98 : : * The Meta page is always the first page in the btree index.
99 : : * Its primary purpose is to point to the location of the btree root page.
100 : : * We also point to the "fast" root, which is the current effective root;
101 : : * see README for discussion.
102 : : */
103 : :
104 : : typedef struct BTMetaPageData
105 : : {
106 : : uint32 btm_magic; /* should contain BTREE_MAGIC */
107 : : uint32 btm_version; /* nbtree version (always <= BTREE_VERSION) */
108 : : BlockNumber btm_root; /* current root location */
109 : : uint32 btm_level; /* tree level of the root page */
110 : : BlockNumber btm_fastroot; /* current "fast" root location */
111 : : uint32 btm_fastlevel; /* tree level of the "fast" root page */
112 : : /* remaining fields only valid when btm_version >= BTREE_NOVAC_VERSION */
113 : :
114 : : /* number of deleted, non-recyclable pages during last cleanup */
115 : : uint32 btm_last_cleanup_num_delpages;
116 : : /* number of heap tuples during last cleanup (deprecated) */
117 : : float8 btm_last_cleanup_num_heap_tuples;
118 : :
119 : : bool btm_allequalimage; /* are all columns "equalimage"? */
120 : : } BTMetaPageData;
121 : :
122 : : #define BTPageGetMeta(p) \
123 : : ((BTMetaPageData *) PageGetContents(p))
124 : :
125 : : /*
126 : : * The current Btree version is 4. That's what you'll get when you create
127 : : * a new index.
128 : : *
129 : : * Btree version 3 was used in PostgreSQL v11. It is mostly the same as
130 : : * version 4, but heap TIDs were not part of the keyspace. Index tuples
131 : : * with duplicate keys could be stored in any order. We continue to
132 : : * support reading and writing Btree versions 2 and 3, so that they don't
133 : : * need to be immediately re-indexed at pg_upgrade. In order to get the
134 : : * new heapkeyspace semantics, however, a REINDEX is needed.
135 : : *
136 : : * Deduplication is safe to use when the btm_allequalimage field is set to
137 : : * true. It's safe to read the btm_allequalimage field on version 3, but
138 : : * only version 4 indexes make use of deduplication. Even version 4
139 : : * indexes created on PostgreSQL v12 will need a REINDEX to make use of
140 : : * deduplication, though, since there is no other way to set
141 : : * btm_allequalimage to true (pg_upgrade hasn't been taught to set the
142 : : * metapage field).
143 : : *
144 : : * Btree version 2 is mostly the same as version 3. There are two new
145 : : * fields in the metapage that were introduced in version 3. A version 2
146 : : * metapage will be automatically upgraded to version 3 on the first
147 : : * insert to it. INCLUDE indexes cannot use version 2.
148 : : */
149 : : #define BTREE_METAPAGE 0 /* first page is meta */
150 : : #define BTREE_MAGIC 0x053162 /* magic number in metapage */
151 : : #define BTREE_VERSION 4 /* current version number */
152 : : #define BTREE_MIN_VERSION 2 /* minimum supported version */
153 : : #define BTREE_NOVAC_VERSION 3 /* version with all meta fields set */
154 : :
155 : : /*
156 : : * Maximum size of a btree index entry, including its tuple header.
157 : : *
158 : : * We actually need to be able to fit three items on every page,
159 : : * so restrict any one item to 1/3 the per-page available space.
160 : : *
161 : : * There are rare cases where _bt_truncate() will need to enlarge
162 : : * a heap index tuple to make space for a tiebreaker heap TID
163 : : * attribute, which we account for here.
164 : : */
165 : : #define BTMaxItemSize \
166 : : (MAXALIGN_DOWN((BLCKSZ - \
167 : : MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
168 : : MAXALIGN(sizeof(BTPageOpaqueData))) / 3) - \
169 : : MAXALIGN(sizeof(ItemPointerData)))
170 : : #define BTMaxItemSizeNoHeapTid \
171 : : MAXALIGN_DOWN((BLCKSZ - \
172 : : MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
173 : : MAXALIGN(sizeof(BTPageOpaqueData))) / 3)
174 : :
175 : : /*
176 : : * MaxTIDsPerBTreePage is an upper bound on the number of heap TIDs tuples
177 : : * that may be stored on a btree leaf page. It is used to size the
178 : : * per-page temporary buffers.
179 : : *
180 : : * Note: we don't bother considering per-tuple overheads here to keep
181 : : * things simple (value is based on how many elements a single array of
182 : : * heap TIDs must have to fill the space between the page header and
183 : : * special area). The value is slightly higher (i.e. more conservative)
184 : : * than necessary as a result, which is considered acceptable.
185 : : */
186 : : #define MaxTIDsPerBTreePage \
187 : : (int) ((BLCKSZ - SizeOfPageHeaderData - sizeof(BTPageOpaqueData)) / \
188 : : sizeof(ItemPointerData))
189 : :
190 : : /*
191 : : * The leaf-page fillfactor defaults to 90% but is user-adjustable.
192 : : * For pages above the leaf level, we use a fixed 70% fillfactor.
193 : : * The fillfactor is applied during index build and when splitting
194 : : * a rightmost page; when splitting non-rightmost pages we try to
195 : : * divide the data equally. When splitting a page that's entirely
196 : : * filled with a single value (duplicates), the effective leaf-page
197 : : * fillfactor is 96%, regardless of whether the page is a rightmost
198 : : * page.
199 : : */
200 : : #define BTREE_MIN_FILLFACTOR 10
201 : : #define BTREE_DEFAULT_FILLFACTOR 90
202 : : #define BTREE_NONLEAF_FILLFACTOR 70
203 : : #define BTREE_SINGLEVAL_FILLFACTOR 96
204 : :
205 : : /*
206 : : * In general, the btree code tries to localize its knowledge about
207 : : * page layout to a couple of routines. However, we need a special
208 : : * value to indicate "no page number" in those places where we expect
209 : : * page numbers. We can use zero for this because we never need to
210 : : * make a pointer to the metadata page.
211 : : */
212 : :
213 : : #define P_NONE 0
214 : :
215 : : /*
216 : : * Macros to test whether a page is leftmost or rightmost on its tree level,
217 : : * as well as other state info kept in the opaque data.
218 : : */
219 : : #define P_LEFTMOST(opaque) ((opaque)->btpo_prev == P_NONE)
220 : : #define P_RIGHTMOST(opaque) ((opaque)->btpo_next == P_NONE)
221 : : #define P_ISLEAF(opaque) (((opaque)->btpo_flags & BTP_LEAF) != 0)
222 : : #define P_ISROOT(opaque) (((opaque)->btpo_flags & BTP_ROOT) != 0)
223 : : #define P_ISDELETED(opaque) (((opaque)->btpo_flags & BTP_DELETED) != 0)
224 : : #define P_ISMETA(opaque) (((opaque)->btpo_flags & BTP_META) != 0)
225 : : #define P_ISHALFDEAD(opaque) (((opaque)->btpo_flags & BTP_HALF_DEAD) != 0)
226 : : #define P_IGNORE(opaque) (((opaque)->btpo_flags & (BTP_DELETED|BTP_HALF_DEAD)) != 0)
227 : : #define P_HAS_GARBAGE(opaque) (((opaque)->btpo_flags & BTP_HAS_GARBAGE) != 0)
228 : : #define P_INCOMPLETE_SPLIT(opaque) (((opaque)->btpo_flags & BTP_INCOMPLETE_SPLIT) != 0)
229 : : #define P_HAS_FULLXID(opaque) (((opaque)->btpo_flags & BTP_HAS_FULLXID) != 0)
230 : :
231 : : /*
232 : : * BTDeletedPageData is the page contents of a deleted page
233 : : */
234 : : typedef struct BTDeletedPageData
235 : : {
236 : : FullTransactionId safexid; /* See BTPageIsRecyclable() */
237 : : } BTDeletedPageData;
238 : :
239 : : static inline void
1706 pg@bowt.ie 240 :CBC 3820 : BTPageSetDeleted(Page page, FullTransactionId safexid)
241 : : {
242 : : BTPageOpaque opaque;
243 : : PageHeader header;
244 : : BTDeletedPageData *contents;
245 : :
1305 michael@paquier.xyz 246 : 3820 : opaque = BTPageGetOpaque(page);
1706 pg@bowt.ie 247 : 3820 : header = ((PageHeader) page);
248 : :
249 : 3820 : opaque->btpo_flags &= ~BTP_HALF_DEAD;
250 : 3820 : opaque->btpo_flags |= BTP_DELETED | BTP_HAS_FULLXID;
251 : 3820 : header->pd_lower = MAXALIGN(SizeOfPageHeaderData) +
252 : : sizeof(BTDeletedPageData);
253 : 3820 : header->pd_upper = header->pd_special;
254 : :
255 : : /* Set safexid in deleted page */
256 : 3820 : contents = ((BTDeletedPageData *) PageGetContents(page));
257 : 3820 : contents->safexid = safexid;
258 : 3820 : }
259 : :
260 : : static inline FullTransactionId
261 : 2402 : BTPageGetDeleteXid(Page page)
262 : : {
263 : : BTPageOpaque opaque;
264 : : BTDeletedPageData *contents;
265 : :
266 : : /* We only expect to be called with a deleted page */
267 [ - + ]: 2402 : Assert(!PageIsNew(page));
1305 michael@paquier.xyz 268 : 2402 : opaque = BTPageGetOpaque(page);
1706 pg@bowt.ie 269 [ - + ]: 2402 : Assert(P_ISDELETED(opaque));
270 : :
271 : : /* pg_upgrade'd deleted page -- must be safe to recycle now */
272 [ - + ]: 2402 : if (!P_HAS_FULLXID(opaque))
1706 pg@bowt.ie 273 :UBC 0 : return FirstNormalFullTransactionId;
274 : :
275 : : /* Get safexid from deleted page */
1706 pg@bowt.ie 276 :CBC 2402 : contents = ((BTDeletedPageData *) PageGetContents(page));
277 : 2402 : return contents->safexid;
278 : : }
279 : :
280 : : /*
281 : : * Is an existing page recyclable?
282 : : *
283 : : * This exists to centralize the policy on which deleted pages are now safe to
284 : : * re-use. However, _bt_pendingfsm_finalize() duplicates some of the same
285 : : * logic because it doesn't work directly with pages -- keep the two in sync.
286 : : *
287 : : * Note: PageIsNew() pages are always safe to recycle, but we can't deal with
288 : : * them here (caller is responsible for that case themselves). Caller might
289 : : * well need special handling for new pages anyway.
290 : : */
291 : : static inline bool
938 292 : 16266 : BTPageIsRecyclable(Page page, Relation heaprel)
293 : : {
294 : : BTPageOpaque opaque;
295 : :
1706 296 [ - + ]: 16266 : Assert(!PageIsNew(page));
870 297 [ - + ]: 16266 : Assert(heaprel != NULL);
298 : :
299 : : /* Recycling okay iff page is deleted and safexid is old enough */
1305 michael@paquier.xyz 300 : 16266 : opaque = BTPageGetOpaque(page);
1706 pg@bowt.ie 301 [ + + ]: 16266 : if (P_ISDELETED(opaque))
302 : : {
870 303 : 2068 : FullTransactionId safexid = BTPageGetDeleteXid(page);
304 : :
305 : : /*
306 : : * The page was deleted, but when? If it was just deleted, a scan
307 : : * might have seen the downlink to it, and will read the page later.
308 : : * As long as that can happen, we must keep the deleted page around as
309 : : * a tombstone.
310 : : *
311 : : * For that check if the deletion XID could still be visible to
312 : : * anyone. If not, then no scan that's still in progress could have
313 : : * seen its downlink, and we can recycle it.
314 : : */
315 : 2068 : return GlobalVisCheckRemovableFullXid(heaprel, safexid);
316 : : }
317 : :
1706 318 : 14198 : return false;
319 : : }
320 : :
321 : : /*
322 : : * BTVacState and BTPendingFSM are private nbtree.c state used during VACUUM.
323 : : * They are exported for use by page deletion related code in nbtpage.c.
324 : : */
325 : : typedef struct BTPendingFSM
326 : : {
327 : : BlockNumber target; /* Page deleted by current VACUUM */
328 : : FullTransactionId safexid; /* Page's BTDeletedPageData.safexid */
329 : : } BTPendingFSM;
330 : :
331 : : typedef struct BTVacState
332 : : {
333 : : IndexVacuumInfo *info;
334 : : IndexBulkDeleteResult *stats;
335 : : IndexBulkDeleteCallback callback;
336 : : void *callback_state;
337 : : BTCycleId cycleid;
338 : : MemoryContext pagedelcontext;
339 : :
340 : : /*
341 : : * _bt_pendingfsm_finalize() state
342 : : */
343 : : int bufsize; /* pendingpages space (in # elements) */
344 : : int maxbufsize; /* max bufsize that respects work_mem */
345 : : BTPendingFSM *pendingpages; /* One entry per newly deleted page */
346 : : int npendingpages; /* current # valid pendingpages */
347 : : } BTVacState;
348 : :
349 : : /*
350 : : * Lehman and Yao's algorithm requires a ``high key'' on every non-rightmost
351 : : * page. The high key is not a tuple that is used to visit the heap. It is
352 : : * a pivot tuple (see "Notes on B-Tree tuple format" below for definition).
353 : : * The high key on a page is required to be greater than or equal to any
354 : : * other key that appears on the page. If we find ourselves trying to
355 : : * insert a key that is strictly > high key, we know we need to move right
356 : : * (this should only happen if the page was split since we examined the
357 : : * parent page).
358 : : *
359 : : * Our insertion algorithm guarantees that we can use the initial least key
360 : : * on our right sibling as the high key. Once a page is created, its high
361 : : * key changes only if the page is split.
362 : : *
363 : : * On a non-rightmost page, the high key lives in item 1 and data items
364 : : * start in item 2. Rightmost pages have no high key, so we store data
365 : : * items beginning in item 1.
366 : : */
367 : :
368 : : #define P_HIKEY ((OffsetNumber) 1)
369 : : #define P_FIRSTKEY ((OffsetNumber) 2)
370 : : #define P_FIRSTDATAKEY(opaque) (P_RIGHTMOST(opaque) ? P_HIKEY : P_FIRSTKEY)
371 : :
372 : : /*
373 : : * Notes on B-Tree tuple format, and key and non-key attributes:
374 : : *
375 : : * INCLUDE B-Tree indexes have non-key attributes. These are extra
376 : : * attributes that may be returned by index-only scans, but do not influence
377 : : * the order of items in the index (formally, non-key attributes are not
378 : : * considered to be part of the key space). Non-key attributes are only
379 : : * present in leaf index tuples whose item pointers actually point to heap
380 : : * tuples (non-pivot tuples). _bt_check_natts() enforces the rules
381 : : * described here.
382 : : *
383 : : * Non-pivot tuple format (plain/non-posting variant):
384 : : *
385 : : * t_tid | t_info | key values | INCLUDE columns, if any
386 : : *
387 : : * t_tid points to the heap TID, which is a tiebreaker key column as of
388 : : * BTREE_VERSION 4.
389 : : *
390 : : * Non-pivot tuples complement pivot tuples, which only have key columns.
391 : : * The sole purpose of pivot tuples is to represent how the key space is
392 : : * separated. In general, any B-Tree index that has more than one level
393 : : * (i.e. any index that does not just consist of a metapage and a single
394 : : * leaf root page) must have some number of pivot tuples, since pivot
395 : : * tuples are used for traversing the tree. Suffix truncation can omit
396 : : * trailing key columns when a new pivot is formed, which makes minus
397 : : * infinity their logical value. Since BTREE_VERSION 4 indexes treat heap
398 : : * TID as a trailing key column that ensures that all index tuples are
399 : : * physically unique, it is necessary to represent heap TID as a trailing
400 : : * key column in pivot tuples, though very often this can be truncated
401 : : * away, just like any other key column. (Actually, the heap TID is
402 : : * omitted rather than truncated, since its representation is different to
403 : : * the non-pivot representation.)
404 : : *
405 : : * Pivot tuple format:
406 : : *
407 : : * t_tid | t_info | key values | [heap TID]
408 : : *
409 : : * We store the number of columns present inside pivot tuples by abusing
410 : : * their t_tid offset field, since pivot tuples never need to store a real
411 : : * offset (pivot tuples generally store a downlink in t_tid, though). The
412 : : * offset field only stores the number of columns/attributes when the
413 : : * INDEX_ALT_TID_MASK bit is set, which doesn't count the trailing heap
414 : : * TID column sometimes stored in pivot tuples -- that's represented by
415 : : * the presence of BT_PIVOT_HEAP_TID_ATTR. The INDEX_ALT_TID_MASK bit in
416 : : * t_info is always set on BTREE_VERSION 4 pivot tuples, since
417 : : * BTreeTupleIsPivot() must work reliably on heapkeyspace versions.
418 : : *
419 : : * In version 2 or version 3 (!heapkeyspace) indexes, INDEX_ALT_TID_MASK
420 : : * might not be set in pivot tuples. BTreeTupleIsPivot() won't work
421 : : * reliably as a result. The number of columns stored is implicitly the
422 : : * same as the number of columns in the index, just like any non-pivot
423 : : * tuple. (The number of columns stored should not vary, since suffix
424 : : * truncation of key columns is unsafe within any !heapkeyspace index.)
425 : : *
426 : : * The 12 least significant bits from t_tid's offset number are used to
427 : : * represent the number of key columns within a pivot tuple. This leaves 4
428 : : * status bits (BT_STATUS_OFFSET_MASK bits), which are shared by all tuples
429 : : * that have the INDEX_ALT_TID_MASK bit set (set in t_info) to store basic
430 : : * tuple metadata. BTreeTupleIsPivot() and BTreeTupleIsPosting() use the
431 : : * BT_STATUS_OFFSET_MASK bits.
432 : : *
433 : : * Sometimes non-pivot tuples also use a representation that repurposes
434 : : * t_tid to store metadata rather than a TID. PostgreSQL v13 introduced a
435 : : * new non-pivot tuple format to support deduplication: posting list
436 : : * tuples. Deduplication merges together multiple equal non-pivot tuples
437 : : * into a logically equivalent, space efficient representation. A posting
438 : : * list is an array of ItemPointerData elements. Non-pivot tuples are
439 : : * merged together to form posting list tuples lazily, at the point where
440 : : * we'd otherwise have to split a leaf page.
441 : : *
442 : : * Posting tuple format (alternative non-pivot tuple representation):
443 : : *
444 : : * t_tid | t_info | key values | posting list (TID array)
445 : : *
446 : : * Posting list tuples are recognized as such by having the
447 : : * INDEX_ALT_TID_MASK status bit set in t_info and the BT_IS_POSTING status
448 : : * bit set in t_tid's offset number. These flags redefine the content of
449 : : * the posting tuple's t_tid to store the location of the posting list
450 : : * (instead of a block number), as well as the total number of heap TIDs
451 : : * present in the tuple (instead of a real offset number).
452 : : *
453 : : * The 12 least significant bits from t_tid's offset number are used to
454 : : * represent the number of heap TIDs present in the tuple, leaving 4 status
455 : : * bits (the BT_STATUS_OFFSET_MASK bits). Like any non-pivot tuple, the
456 : : * number of columns stored is always implicitly the total number in the
457 : : * index (in practice there can never be non-key columns stored, since
458 : : * deduplication is not supported with INCLUDE indexes).
459 : : */
460 : : #define INDEX_ALT_TID_MASK INDEX_AM_RESERVED_BIT
461 : :
462 : : /* Item pointer offset bit masks */
463 : : #define BT_OFFSET_MASK 0x0FFF
464 : : #define BT_STATUS_OFFSET_MASK 0xF000
465 : : /* BT_STATUS_OFFSET_MASK status bits */
466 : : #define BT_PIVOT_HEAP_TID_ATTR 0x1000
467 : : #define BT_IS_POSTING 0x2000
468 : :
469 : : /*
470 : : * Mask allocated for number of keys in index tuple must be able to fit
471 : : * maximum possible number of index attributes
472 : : */
473 : : StaticAssertDecl(BT_OFFSET_MASK >= INDEX_MAX_KEYS,
474 : : "BT_OFFSET_MASK can't fit INDEX_MAX_KEYS");
475 : :
476 : : /*
477 : : * Note: BTreeTupleIsPivot() can have false negatives (but not false
478 : : * positives) when used with !heapkeyspace indexes
479 : : */
480 : : static inline bool
2070 481 : 564007606 : BTreeTupleIsPivot(IndexTuple itup)
482 : : {
483 [ + + ]: 564007606 : if ((itup->t_info & INDEX_ALT_TID_MASK) == 0)
484 : 380233062 : return false;
485 : : /* absence of BT_IS_POSTING in offset number indicates pivot tuple */
486 [ + + ]: 183774544 : if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) & BT_IS_POSTING) != 0)
487 : 7464250 : return false;
488 : :
489 : 176310294 : return true;
490 : : }
491 : :
492 : : static inline bool
493 : 438067784 : BTreeTupleIsPosting(IndexTuple itup)
494 : : {
495 [ + + ]: 438067784 : if ((itup->t_info & INDEX_ALT_TID_MASK) == 0)
496 : 267301033 : return false;
497 : : /* presence of BT_IS_POSTING in offset number indicates posting tuple */
498 [ + + ]: 170766751 : if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) & BT_IS_POSTING) == 0)
499 : 128772031 : return false;
500 : :
501 : 41994720 : return true;
502 : : }
503 : :
504 : : static inline void
2014 505 : 226655 : BTreeTupleSetPosting(IndexTuple itup, uint16 nhtids, int postingoffset)
506 : : {
507 [ - + ]: 226655 : Assert(nhtids > 1);
508 [ - + ]: 226655 : Assert((nhtids & BT_STATUS_OFFSET_MASK) == 0);
2065 509 [ - + ]: 226655 : Assert((size_t) postingoffset == MAXALIGN(postingoffset));
2070 510 [ - + ]: 226655 : Assert(postingoffset < INDEX_SIZE_MASK);
2014 511 [ - + ]: 226655 : Assert(!BTreeTupleIsPivot(itup));
512 : :
2070 513 : 226655 : itup->t_info |= INDEX_ALT_TID_MASK;
514 : 226655 : ItemPointerSetOffsetNumber(&itup->t_tid, (nhtids | BT_IS_POSTING));
515 : 226655 : ItemPointerSetBlockNumber(&itup->t_tid, postingoffset);
516 : 226655 : }
517 : :
518 : : static inline uint16
519 : 15332522 : BTreeTupleGetNPosting(IndexTuple posting)
520 : : {
521 : : OffsetNumber existing;
522 : :
523 [ - + ]: 15332522 : Assert(BTreeTupleIsPosting(posting));
524 : :
525 : 15332522 : existing = ItemPointerGetOffsetNumberNoCheck(&posting->t_tid);
526 : 15332522 : return (existing & BT_OFFSET_MASK);
527 : : }
528 : :
529 : : static inline uint32
530 : 17013948 : BTreeTupleGetPostingOffset(IndexTuple posting)
531 : : {
532 [ - + ]: 17013948 : Assert(BTreeTupleIsPosting(posting));
533 : :
534 : 17013948 : return ItemPointerGetBlockNumberNoCheck(&posting->t_tid);
535 : : }
536 : :
537 : : static inline ItemPointer
538 : 15811588 : BTreeTupleGetPosting(IndexTuple posting)
539 : : {
540 : 31623176 : return (ItemPointer) ((char *) posting +
541 : 15811588 : BTreeTupleGetPostingOffset(posting));
542 : : }
543 : :
544 : : static inline ItemPointer
545 : 13840944 : BTreeTupleGetPostingN(IndexTuple posting, int n)
546 : : {
547 : 13840944 : return BTreeTupleGetPosting(posting) + n;
548 : : }
549 : :
550 : : /*
551 : : * Get/set downlink block number in pivot tuple.
552 : : *
553 : : * Note: Cannot assert that tuple is a pivot tuple. If we did so then
554 : : * !heapkeyspace indexes would exhibit false positive assertion failures.
555 : : */
556 : : static inline BlockNumber
557 : 8897259 : BTreeTupleGetDownLink(IndexTuple pivot)
558 : : {
559 : 8897259 : return ItemPointerGetBlockNumberNoCheck(&pivot->t_tid);
560 : : }
561 : :
562 : : static inline void
563 : 37128 : BTreeTupleSetDownLink(IndexTuple pivot, BlockNumber blkno)
564 : : {
565 : 37128 : ItemPointerSetBlockNumber(&pivot->t_tid, blkno);
566 : 37128 : }
567 : :
568 : : /*
569 : : * Get number of attributes within tuple.
570 : : *
571 : : * Note that this does not include an implicit tiebreaker heap TID
572 : : * attribute, if any. Note also that the number of key attributes must be
573 : : * explicitly represented in all heapkeyspace pivot tuples.
574 : : *
575 : : * Note: This is defined as a macro rather than an inline function to
576 : : * avoid including rel.h.
577 : : */
578 : : #define BTreeTupleGetNAtts(itup, rel) \
579 : : ( \
580 : : (BTreeTupleIsPivot(itup)) ? \
581 : : ( \
582 : : ItemPointerGetOffsetNumberNoCheck(&(itup)->t_tid) & BT_OFFSET_MASK \
583 : : ) \
584 : : : \
585 : : IndexRelationGetNumberOfAttributes(rel) \
586 : : )
587 : :
588 : : /*
589 : : * Set number of key attributes in tuple.
590 : : *
591 : : * The heap TID tiebreaker attribute bit may also be set here, indicating that
592 : : * a heap TID value will be stored at the end of the tuple (i.e. using the
593 : : * special pivot tuple representation).
594 : : */
595 : : static inline void
2029 596 : 43655 : BTreeTupleSetNAtts(IndexTuple itup, uint16 nkeyatts, bool heaptid)
597 : : {
598 [ - + ]: 43655 : Assert(nkeyatts <= INDEX_MAX_KEYS);
2014 599 [ - + ]: 43655 : Assert((nkeyatts & BT_STATUS_OFFSET_MASK) == 0);
2029 600 [ + + - + ]: 43655 : Assert(!heaptid || nkeyatts > 0);
601 [ + + - + ]: 43655 : Assert(!BTreeTupleIsPivot(itup) || nkeyatts == 0);
602 : :
2070 603 : 43655 : itup->t_info |= INDEX_ALT_TID_MASK;
604 : :
2029 605 [ + + ]: 43655 : if (heaptid)
606 : 540 : nkeyatts |= BT_PIVOT_HEAP_TID_ATTR;
607 : :
608 : : /* BT_IS_POSTING bit is deliberately unset here */
609 : 43655 : ItemPointerSetOffsetNumber(&itup->t_tid, nkeyatts);
610 [ - + ]: 43655 : Assert(BTreeTupleIsPivot(itup));
2070 611 : 43655 : }
612 : :
613 : : /*
614 : : * Get/set leaf page's "top parent" link from its high key. Used during page
615 : : * deletion.
616 : : *
617 : : * Note: Cannot assert that tuple is a pivot tuple. If we did so then
618 : : * !heapkeyspace indexes would exhibit false positive assertion failures.
619 : : */
620 : : static inline BlockNumber
621 : 3112 : BTreeTupleGetTopParent(IndexTuple leafhikey)
622 : : {
623 : 3112 : return ItemPointerGetBlockNumberNoCheck(&leafhikey->t_tid);
624 : : }
625 : :
626 : : static inline void
627 : 3821 : BTreeTupleSetTopParent(IndexTuple leafhikey, BlockNumber blkno)
628 : : {
629 : 3821 : ItemPointerSetBlockNumber(&leafhikey->t_tid, blkno);
2029 630 : 3821 : BTreeTupleSetNAtts(leafhikey, 0, false);
2070 631 : 3821 : }
632 : :
633 : : /*
634 : : * Get tiebreaker heap TID attribute, if any.
635 : : *
636 : : * This returns the first/lowest heap TID in the case of a posting list tuple.
637 : : */
638 : : static inline ItemPointer
639 : 58757558 : BTreeTupleGetHeapTID(IndexTuple itup)
640 : : {
641 [ + + ]: 58757558 : if (BTreeTupleIsPivot(itup))
642 : : {
643 : : /* Pivot tuple heap TID representation? */
644 [ + + ]: 41538874 : if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) &
645 : : BT_PIVOT_HEAP_TID_ATTR) != 0)
646 : 381136 : return (ItemPointer) ((char *) itup + IndexTupleSize(itup) -
647 : : sizeof(ItemPointerData));
648 : :
649 : : /* Heap TID attribute was truncated */
650 : 41157738 : return NULL;
651 : : }
652 [ + + ]: 17218684 : else if (BTreeTupleIsPosting(itup))
653 : 675922 : return BTreeTupleGetPosting(itup);
654 : :
655 : 16542762 : return &itup->t_tid;
656 : : }
657 : :
658 : : /*
659 : : * Get maximum heap TID attribute, which could be the only TID in the case of
660 : : * a non-pivot tuple that does not have a posting list.
661 : : *
662 : : * Works with non-pivot tuples only.
663 : : */
664 : : static inline ItemPointer
665 : 157887 : BTreeTupleGetMaxHeapTID(IndexTuple itup)
666 : : {
667 [ - + ]: 157887 : Assert(!BTreeTupleIsPivot(itup));
668 : :
669 [ + + ]: 157887 : if (BTreeTupleIsPosting(itup))
670 : : {
671 : 157377 : uint16 nposting = BTreeTupleGetNPosting(itup);
672 : :
673 : 157377 : return BTreeTupleGetPostingN(itup, nposting - 1);
674 : : }
675 : :
676 : 510 : return &itup->t_tid;
677 : : }
678 : :
679 : : /*
680 : : * Operator strategy numbers for B-tree have been moved to access/stratnum.h,
681 : : * because many places need to use them in ScanKeyInit() calls.
682 : : *
683 : : * The strategy numbers are chosen so that we can commute them by
684 : : * subtraction, thus:
685 : : */
686 : : #define BTCommuteStrategyNumber(strat) (BTMaxStrategyNumber + 1 - (strat))
687 : :
688 : : /*
689 : : * When a new operator class is declared, we require that the user
690 : : * supply us with an amproc procedure (BTORDER_PROC) for determining
691 : : * whether, for two keys a and b, a < b, a = b, or a > b. This routine
692 : : * must return < 0, 0, > 0, respectively, in these three cases.
693 : : *
694 : : * To facilitate accelerated sorting, an operator class may choose to
695 : : * offer a second procedure (BTSORTSUPPORT_PROC). For full details, see
696 : : * src/include/utils/sortsupport.h.
697 : : *
698 : : * To support window frames defined by "RANGE offset PRECEDING/FOLLOWING",
699 : : * an operator class may choose to offer a third amproc procedure
700 : : * (BTINRANGE_PROC), independently of whether it offers sortsupport.
701 : : * For full details, see doc/src/sgml/btree.sgml.
702 : : *
703 : : * To facilitate B-Tree deduplication, an operator class may choose to
704 : : * offer a forth amproc procedure (BTEQUALIMAGE_PROC). For full details,
705 : : * see doc/src/sgml/btree.sgml.
706 : : *
707 : : * An operator class may choose to offer a fifth amproc procedure
708 : : * (BTOPTIONS_PROC). These procedures define a set of user-visible
709 : : * parameters that can be used to control operator class behavior. None of
710 : : * the built-in B-Tree operator classes currently register an "options" proc.
711 : : *
712 : : * To facilitate more efficient B-Tree skip scans, an operator class may
713 : : * choose to offer a sixth amproc procedure (BTSKIPSUPPORT_PROC). For full
714 : : * details, see src/include/utils/skipsupport.h.
715 : : */
716 : :
717 : : #define BTORDER_PROC 1
718 : : #define BTSORTSUPPORT_PROC 2
719 : : #define BTINRANGE_PROC 3
720 : : #define BTEQUALIMAGE_PROC 4
721 : : #define BTOPTIONS_PROC 5
722 : : #define BTSKIPSUPPORT_PROC 6
723 : : #define BTNProcs 6
724 : :
725 : : /*
726 : : * We need to be able to tell the difference between read and write
727 : : * requests for pages, in order to do locking correctly.
728 : : */
729 : :
730 : : #define BT_READ BUFFER_LOCK_SHARE
731 : : #define BT_WRITE BUFFER_LOCK_EXCLUSIVE
732 : :
733 : : /*
734 : : * BTStackData -- As we descend a tree, we push the location of pivot
735 : : * tuples whose downlink we are about to follow onto a private stack. If
736 : : * we split a leaf, we use this stack to walk back up the tree and insert
737 : : * data into its parent page at the correct location. We also have to
738 : : * recursively insert into the grandparent page if and when the parent page
739 : : * splits. Our private stack can become stale due to concurrent page
740 : : * splits and page deletions, but it should never give us an irredeemably
741 : : * bad picture.
742 : : */
743 : : typedef struct BTStackData
744 : : {
745 : : BlockNumber bts_blkno;
746 : : OffsetNumber bts_offset;
747 : : struct BTStackData *bts_parent;
748 : : } BTStackData;
749 : :
750 : : typedef BTStackData *BTStack;
751 : :
752 : : /*
753 : : * BTScanInsertData is the btree-private state needed to find an initial
754 : : * position for an indexscan, or to insert new tuples -- an "insertion
755 : : * scankey" (not to be confused with a search scankey). It's used to descend
756 : : * a B-Tree using _bt_search.
757 : : *
758 : : * heapkeyspace indicates if we expect all keys in the index to be physically
759 : : * unique because heap TID is used as a tiebreaker attribute, and if index may
760 : : * have truncated key attributes in pivot tuples. This is actually a property
761 : : * of the index relation itself (not an indexscan). heapkeyspace indexes are
762 : : * indexes whose version is >= version 4. It's convenient to keep this close
763 : : * by, rather than accessing the metapage repeatedly.
764 : : *
765 : : * allequalimage is set to indicate that deduplication is safe for the index.
766 : : * This is also a property of the index relation rather than an indexscan.
767 : : *
768 : : * anynullkeys indicates if any of the keys had NULL value when scankey was
769 : : * built from index tuple (note that already-truncated tuple key attributes
770 : : * set NULL as a placeholder key value, which also affects value of
771 : : * anynullkeys). This is a convenience for unique index non-pivot tuple
772 : : * insertion, which usually temporarily unsets scantid, but shouldn't iff
773 : : * anynullkeys is true. Value generally matches non-pivot tuple's HasNulls
774 : : * bit, but may not when inserting into an INCLUDE index (tuple header value
775 : : * is affected by the NULL-ness of both key and non-key attributes).
776 : : *
777 : : * See comments in _bt_first for an explanation of the nextkey and backward
778 : : * fields.
779 : : *
780 : : * scantid is the heap TID that is used as a final tiebreaker attribute. It
781 : : * is set to NULL when index scan doesn't need to find a position for a
782 : : * specific physical tuple. Must be set when inserting new tuples into
783 : : * heapkeyspace indexes, since every tuple in the tree unambiguously belongs
784 : : * in one exact position (it's never set with !heapkeyspace indexes, though).
785 : : * Despite the representational difference, nbtree search code considers
786 : : * scantid to be just another insertion scankey attribute.
787 : : *
788 : : * scankeys is an array of scan key entries for attributes that are compared
789 : : * before scantid (user-visible attributes). keysz is the size of the array.
790 : : * During insertion, there must be a scan key for every attribute, but when
791 : : * starting a regular index scan some can be omitted. The array is used as a
792 : : * flexible array member, though it's sized in a way that makes it possible to
793 : : * use stack allocations. See nbtree/README for full details.
794 : : */
795 : : typedef struct BTScanInsertData
796 : : {
797 : : bool heapkeyspace;
798 : : bool allequalimage;
799 : : bool anynullkeys;
800 : : bool nextkey;
801 : : bool backward; /* backward index scan? */
802 : : ItemPointer scantid; /* tiebreaker for scankeys */
803 : : int keysz; /* Size of scankeys array */
804 : : ScanKeyData scankeys[INDEX_MAX_KEYS]; /* Must appear last */
805 : : } BTScanInsertData;
806 : :
807 : : typedef BTScanInsertData *BTScanInsert;
808 : :
809 : : /*
810 : : * BTInsertStateData is a working area used during insertion.
811 : : *
812 : : * This is filled in after descending the tree to the first leaf page the new
813 : : * tuple might belong on. Tracks the current position while performing
814 : : * uniqueness check, before we have determined which exact page to insert
815 : : * to.
816 : : *
817 : : * (This should be private to nbtinsert.c, but it's also used by
818 : : * _bt_binsrch_insert)
819 : : */
820 : : typedef struct BTInsertStateData
821 : : {
822 : : IndexTuple itup; /* Item we're inserting */
823 : : Size itemsz; /* Size of itup -- should be MAXALIGN()'d */
824 : : BTScanInsert itup_key; /* Insertion scankey */
825 : :
826 : : /* Buffer containing leaf page we're likely to insert itup on */
827 : : Buffer buf;
828 : :
829 : : /*
830 : : * Cache of bounds within the current buffer. Only used for insertions
831 : : * where _bt_check_unique is called. See _bt_binsrch_insert and
832 : : * _bt_findinsertloc for details.
833 : : */
834 : : bool bounds_valid;
835 : : OffsetNumber low;
836 : : OffsetNumber stricthigh;
837 : :
838 : : /*
839 : : * if _bt_binsrch_insert found the location inside existing posting list,
840 : : * save the position inside the list. -1 sentinel value indicates overlap
841 : : * with an existing posting list tuple that has its LP_DEAD bit set.
842 : : */
843 : : int postingoff;
844 : : } BTInsertStateData;
845 : :
846 : : typedef BTInsertStateData *BTInsertState;
847 : :
848 : : /*
849 : : * State used to representing an individual pending tuple during
850 : : * deduplication.
851 : : */
852 : : typedef struct BTDedupInterval
853 : : {
854 : : OffsetNumber baseoff;
855 : : uint16 nitems;
856 : : } BTDedupInterval;
857 : :
858 : : /*
859 : : * BTDedupStateData is a working area used during deduplication.
860 : : *
861 : : * The status info fields track the state of a whole-page deduplication pass.
862 : : * State about the current pending posting list is also tracked.
863 : : *
864 : : * A pending posting list is comprised of a contiguous group of equal items
865 : : * from the page, starting from page offset number 'baseoff'. This is the
866 : : * offset number of the "base" tuple for new posting list. 'nitems' is the
867 : : * current total number of existing items from the page that will be merged to
868 : : * make a new posting list tuple, including the base tuple item. (Existing
869 : : * items may themselves be posting list tuples, or regular non-pivot tuples.)
870 : : *
871 : : * The total size of the existing tuples to be freed when pending posting list
872 : : * is processed gets tracked by 'phystupsize'. This information allows
873 : : * deduplication to calculate the space saving for each new posting list
874 : : * tuple, and for the entire pass over the page as a whole.
875 : : */
876 : : typedef struct BTDedupStateData
877 : : {
878 : : /* Deduplication status info for entire pass over page */
879 : : bool deduplicate; /* Still deduplicating page? */
880 : : int nmaxitems; /* Number of max-sized tuples so far */
881 : : Size maxpostingsize; /* Limit on size of final tuple */
882 : :
883 : : /* Metadata about base tuple of current pending posting list */
884 : : IndexTuple base; /* Use to form new posting list */
885 : : OffsetNumber baseoff; /* page offset of base */
886 : : Size basetupsize; /* base size without original posting list */
887 : :
888 : : /* Other metadata about pending posting list */
889 : : ItemPointer htids; /* Heap TIDs in pending posting list */
890 : : int nhtids; /* Number of heap TIDs in htids array */
891 : : int nitems; /* Number of existing tuples/line pointers */
892 : : Size phystupsize; /* Includes line pointer overhead */
893 : :
894 : : /*
895 : : * Array of tuples to go on new version of the page. Contains one entry
896 : : * for each group of consecutive items. Note that existing tuples that
897 : : * will not become posting list tuples do not appear in the array (they
898 : : * are implicitly unchanged by deduplication pass).
899 : : */
900 : : int nintervals; /* current number of intervals in array */
901 : : BTDedupInterval intervals[MaxIndexTuplesPerPage];
902 : : } BTDedupStateData;
903 : :
904 : : typedef BTDedupStateData *BTDedupState;
905 : :
906 : : /*
907 : : * BTVacuumPostingData is state that represents how to VACUUM (or delete) a
908 : : * posting list tuple when some (though not all) of its TIDs are to be
909 : : * deleted.
910 : : *
911 : : * Convention is that itup field is the original posting list tuple on input,
912 : : * and palloc()'d final tuple used to overwrite existing tuple on output.
913 : : */
914 : : typedef struct BTVacuumPostingData
915 : : {
916 : : /* Tuple that will be/was updated */
917 : : IndexTuple itup;
918 : : OffsetNumber updatedoffset;
919 : :
920 : : /* State needed to describe final itup in WAL */
921 : : uint16 ndeletedtids;
922 : : uint16 deletetids[FLEXIBLE_ARRAY_MEMBER];
923 : : } BTVacuumPostingData;
924 : :
925 : : typedef BTVacuumPostingData *BTVacuumPosting;
926 : :
927 : : /*
928 : : * BTScanOpaqueData is the btree-private state needed for an indexscan.
929 : : * This consists of preprocessed scan keys (see _bt_preprocess_keys() for
930 : : * details of the preprocessing), information about the current location
931 : : * of the scan, and information about the marked location, if any. (We use
932 : : * BTScanPosData to represent the data needed for each of current and marked
933 : : * locations.) In addition we can remember some known-killed index entries
934 : : * that must be marked before we can move off the current page.
935 : : *
936 : : * Index scans work a page at a time: we pin and read-lock the page, identify
937 : : * all the matching items on the page and save them in BTScanPosData, then
938 : : * release the read-lock while returning the items to the caller for
939 : : * processing. This approach minimizes lock/unlock traffic. We must always
940 : : * drop the lock to make it okay for caller to process the returned items.
941 : : * Whether or not we can also release the pin during this window will vary.
942 : : * We drop the pin (when so->dropPin) to avoid blocking progress by VACUUM
943 : : * (see nbtree/README section about making concurrent TID recycling safe).
944 : : * We'll always release both the lock and the pin on the current page before
945 : : * moving on to its sibling page.
946 : : *
947 : : * If we are doing an index-only scan, we save the entire IndexTuple for each
948 : : * matched item, otherwise only its heap TID and offset. The IndexTuples go
949 : : * into a separate workspace array; each BTScanPosItem stores its tuple's
950 : : * offset within that array. Posting list tuples store a "base" tuple once,
951 : : * allowing the same key to be returned for each TID in the posting list
952 : : * tuple.
953 : : */
954 : :
955 : : typedef struct BTScanPosItem /* what we remember about each match */
956 : : {
957 : : ItemPointerData heapTid; /* TID of referenced heap item */
958 : : OffsetNumber indexOffset; /* index item's location within page */
959 : : LocationIndex tupleOffset; /* IndexTuple's offset in workspace, if any */
960 : : } BTScanPosItem;
961 : :
962 : : typedef struct BTScanPosData
963 : : {
964 : : Buffer buf; /* currPage buf (invalid means unpinned) */
965 : :
966 : : /* page details as of the saved position's call to _bt_readpage */
967 : : BlockNumber currPage; /* page referenced by items array */
968 : : BlockNumber prevPage; /* currPage's left link */
969 : : BlockNumber nextPage; /* currPage's right link */
970 : : XLogRecPtr lsn; /* currPage's LSN (when so->dropPin) */
971 : :
972 : : /* scan direction for the saved position's call to _bt_readpage */
973 : : ScanDirection dir;
974 : :
975 : : /*
976 : : * If we are doing an index-only scan, nextTupleOffset is the first free
977 : : * location in the associated tuple storage workspace.
978 : : */
979 : : int nextTupleOffset;
980 : :
981 : : /*
982 : : * moreLeft and moreRight track whether we think there may be matching
983 : : * index entries to the left and right of the current page, respectively.
984 : : */
985 : : bool moreLeft;
986 : : bool moreRight;
987 : :
988 : : /*
989 : : * The items array is always ordered in index order (ie, increasing
990 : : * indexoffset). When scanning backwards it is convenient to fill the
991 : : * array back-to-front, so we start at the last slot and fill downwards.
992 : : * Hence we need both a first-valid-entry and a last-valid-entry counter.
993 : : * itemIndex is a cursor showing which entry was last returned to caller.
994 : : */
995 : : int firstItem; /* first valid index in items[] */
996 : : int lastItem; /* last valid index in items[] */
997 : : int itemIndex; /* current index in items[] */
998 : :
999 : : BTScanPosItem items[MaxTIDsPerBTreePage]; /* MUST BE LAST */
1000 : : } BTScanPosData;
1001 : :
1002 : : typedef BTScanPosData *BTScanPos;
1003 : :
1004 : : #define BTScanPosIsPinned(scanpos) \
1005 : : ( \
1006 : : AssertMacro(BlockNumberIsValid((scanpos).currPage) || \
1007 : : !BufferIsValid((scanpos).buf)), \
1008 : : BufferIsValid((scanpos).buf) \
1009 : : )
1010 : : #define BTScanPosUnpin(scanpos) \
1011 : : do { \
1012 : : ReleaseBuffer((scanpos).buf); \
1013 : : (scanpos).buf = InvalidBuffer; \
1014 : : } while (0)
1015 : : #define BTScanPosUnpinIfPinned(scanpos) \
1016 : : do { \
1017 : : if (BTScanPosIsPinned(scanpos)) \
1018 : : BTScanPosUnpin(scanpos); \
1019 : : } while (0)
1020 : :
1021 : : #define BTScanPosIsValid(scanpos) \
1022 : : ( \
1023 : : AssertMacro(BlockNumberIsValid((scanpos).currPage) || \
1024 : : !BufferIsValid((scanpos).buf)), \
1025 : : BlockNumberIsValid((scanpos).currPage) \
1026 : : )
1027 : : #define BTScanPosInvalidate(scanpos) \
1028 : : do { \
1029 : : (scanpos).buf = InvalidBuffer; \
1030 : : (scanpos).currPage = InvalidBlockNumber; \
1031 : : } while (0)
1032 : :
1033 : : /* We need one of these for each equality-type SK_SEARCHARRAY scan key */
1034 : : typedef struct BTArrayKeyInfo
1035 : : {
1036 : : /* fields set for both kinds of array (SAOP arrays and skip arrays) */
1037 : : int scan_key; /* index of associated key in keyData */
1038 : : int num_elems; /* number of elems (-1 means skip array) */
1039 : :
1040 : : /* fields set for ScalarArrayOpExpr arrays only */
1041 : : Datum *elem_values; /* array of num_elems Datums */
1042 : : int cur_elem; /* index of current element in elem_values */
1043 : :
1044 : : /* fields set for skip arrays only */
1045 : : int16 attlen; /* attr's length, in bytes */
1046 : : bool attbyval; /* attr's FormData_pg_attribute.attbyval */
1047 : : bool null_elem; /* NULL is lowest/highest element? */
1048 : : SkipSupport sksup; /* skip support (NULL if opclass lacks it) */
1049 : : ScanKey low_compare; /* array's > or >= lower bound */
1050 : : ScanKey high_compare; /* array's < or <= upper bound */
1051 : : } BTArrayKeyInfo;
1052 : :
1053 : : typedef struct BTScanOpaqueData
1054 : : {
1055 : : /* these fields are set by _bt_preprocess_keys(): */
1056 : : bool qual_ok; /* false if qual can never be satisfied */
1057 : : int numberOfKeys; /* number of preprocessed scan keys */
1058 : : ScanKey keyData; /* array of preprocessed scan keys */
1059 : :
1060 : : /* workspace for SK_SEARCHARRAY support */
1061 : : int numArrayKeys; /* number of equality-type array keys */
1062 : : bool skipScan; /* At least one skip array in arrayKeys[]? */
1063 : : bool needPrimScan; /* New prim scan to continue in current dir? */
1064 : : bool scanBehind; /* Check scan not still behind on next page? */
1065 : : bool oppositeDirCheck; /* scanBehind opposite-scan-dir check? */
1066 : : BTArrayKeyInfo *arrayKeys; /* info about each equality-type array key */
1067 : : FmgrInfo *orderProcs; /* ORDER procs for required equality keys */
1068 : : MemoryContext arrayContext; /* scan-lifespan context for array data */
1069 : :
1070 : : /* info about killed items if any (killedItems is NULL if never used) */
1071 : : int *killedItems; /* currPos.items indexes of killed items */
1072 : : int numKilled; /* number of currently stored items */
1073 : : bool dropPin; /* drop leaf pin before btgettuple returns? */
1074 : :
1075 : : /*
1076 : : * If we are doing an index-only scan, these are the tuple storage
1077 : : * workspaces for the currPos and markPos respectively. Each is of size
1078 : : * BLCKSZ, so it can hold as much as a full page's worth of tuples.
1079 : : */
1080 : : char *currTuples; /* tuple storage for currPos */
1081 : : char *markTuples; /* tuple storage for markPos */
1082 : :
1083 : : /*
1084 : : * If the marked position is on the same page as current position, we
1085 : : * don't use markPos, but just keep the marked itemIndex in markItemIndex
1086 : : * (all the rest of currPos is valid for the mark position). Hence, to
1087 : : * determine if there is a mark, first look at markItemIndex, then at
1088 : : * markPos.
1089 : : */
1090 : : int markItemIndex; /* itemIndex, or -1 if not valid */
1091 : :
1092 : : /* keep these last in struct for efficiency */
1093 : : BTScanPosData currPos; /* current position data */
1094 : : BTScanPosData markPos; /* marked position, if any */
1095 : : } BTScanOpaqueData;
1096 : :
1097 : : typedef BTScanOpaqueData *BTScanOpaque;
1098 : :
1099 : : /*
1100 : : * _bt_readpage state used across _bt_checkkeys calls for a page
1101 : : */
1102 : : typedef struct BTReadPageState
1103 : : {
1104 : : /* Input parameters, set by _bt_readpage for _bt_checkkeys */
1105 : : OffsetNumber minoff; /* Lowest non-pivot tuple's offset */
1106 : : OffsetNumber maxoff; /* Highest non-pivot tuple's offset */
1107 : : IndexTuple finaltup; /* Needed by scans with array keys */
1108 : : Page page; /* Page being read */
1109 : : bool firstpage; /* page is first for primitive scan? */
1110 : : bool forcenonrequired; /* treat all keys as nonrequired? */
1111 : : int startikey; /* start comparisons from this scan key */
1112 : :
1113 : : /* Per-tuple input parameters, set by _bt_readpage for _bt_checkkeys */
1114 : : OffsetNumber offnum; /* current tuple's page offset number */
1115 : :
1116 : : /* Output parameters, set by _bt_checkkeys for _bt_readpage */
1117 : : OffsetNumber skip; /* Array keys "look ahead" skip offnum */
1118 : : bool continuescan; /* Terminate ongoing (primitive) index scan? */
1119 : :
1120 : : /*
1121 : : * Private _bt_checkkeys state used to manage "look ahead" optimization
1122 : : * and primscan scheduling (only used during scans with array keys)
1123 : : */
1124 : : int16 rechecks;
1125 : : int16 targetdistance;
1126 : : int16 nskipadvances;
1127 : :
1128 : : } BTReadPageState;
1129 : :
1130 : : /*
1131 : : * We use some private sk_flags bits in preprocessed scan keys. We're allowed
1132 : : * to use bits 16-31 (see skey.h). The uppermost bits are copied from the
1133 : : * index's indoption[] array entry for the index attribute.
1134 : : */
1135 : : #define SK_BT_REQFWD 0x00010000 /* required to continue forward scan */
1136 : : #define SK_BT_REQBKWD 0x00020000 /* required to continue backward scan */
1137 : : #define SK_BT_SKIP 0x00040000 /* skip array on column without input = */
1138 : :
1139 : : /* SK_BT_SKIP-only flags (set and unset by array advancement) */
1140 : : #define SK_BT_MINVAL 0x00080000 /* invalid sk_argument, use low_compare */
1141 : : #define SK_BT_MAXVAL 0x00100000 /* invalid sk_argument, use high_compare */
1142 : : #define SK_BT_NEXT 0x00200000 /* positions the scan > sk_argument */
1143 : : #define SK_BT_PRIOR 0x00400000 /* positions the scan < sk_argument */
1144 : :
1145 : : /* Remaps pg_index flag bits to uppermost SK_BT_* byte */
1146 : : #define SK_BT_INDOPTION_SHIFT 24 /* must clear the above bits */
1147 : : #define SK_BT_DESC (INDOPTION_DESC << SK_BT_INDOPTION_SHIFT)
1148 : : #define SK_BT_NULLS_FIRST (INDOPTION_NULLS_FIRST << SK_BT_INDOPTION_SHIFT)
1149 : :
1150 : : typedef struct BTOptions
1151 : : {
1152 : : int32 varlena_header_; /* varlena header (do not touch directly!) */
1153 : : int fillfactor; /* page fill factor in percent (0..100) */
1154 : : float8 vacuum_cleanup_index_scale_factor; /* deprecated */
1155 : : bool deduplicate_items; /* Try to deduplicate items? */
1156 : : } BTOptions;
1157 : :
1158 : : #define BTGetFillFactor(relation) \
1159 : : (AssertMacro(relation->rd_rel->relkind == RELKIND_INDEX && \
1160 : : relation->rd_rel->relam == BTREE_AM_OID), \
1161 : : (relation)->rd_options ? \
1162 : : ((BTOptions *) (relation)->rd_options)->fillfactor : \
1163 : : BTREE_DEFAULT_FILLFACTOR)
1164 : : #define BTGetTargetPageFreeSpace(relation) \
1165 : : (BLCKSZ * (100 - BTGetFillFactor(relation)) / 100)
1166 : : #define BTGetDeduplicateItems(relation) \
1167 : : (AssertMacro(relation->rd_rel->relkind == RELKIND_INDEX && \
1168 : : relation->rd_rel->relam == BTREE_AM_OID), \
1169 : : ((relation)->rd_options ? \
1170 : : ((BTOptions *) (relation)->rd_options)->deduplicate_items : true))
1171 : :
1172 : : /*
1173 : : * Constant definition for progress reporting. Phase numbers must match
1174 : : * btbuildphasename.
1175 : : */
1176 : : /* PROGRESS_CREATEIDX_SUBPHASE_INITIALIZE is 1 (see progress.h) */
1177 : : #define PROGRESS_BTREE_PHASE_INDEXBUILD_TABLESCAN 2
1178 : : #define PROGRESS_BTREE_PHASE_PERFORMSORT_1 3
1179 : : #define PROGRESS_BTREE_PHASE_PERFORMSORT_2 4
1180 : : #define PROGRESS_BTREE_PHASE_LEAF_LOAD 5
1181 : :
1182 : : /*
1183 : : * external entry points for btree, in nbtree.c
1184 : : */
1185 : : extern void btbuildempty(Relation index);
1186 : : extern bool btinsert(Relation rel, Datum *values, bool *isnull,
1187 : : ItemPointer ht_ctid, Relation heapRel,
1188 : : IndexUniqueCheck checkUnique,
1189 : : bool indexUnchanged,
1190 : : struct IndexInfo *indexInfo);
1191 : : extern IndexScanDesc btbeginscan(Relation rel, int nkeys, int norderbys);
1192 : : extern Size btestimateparallelscan(Relation rel, int nkeys, int norderbys);
1193 : : extern void btinitparallelscan(void *target);
1194 : : extern bool btgettuple(IndexScanDesc scan, ScanDirection dir);
1195 : : extern int64 btgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
1196 : : extern void btrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
1197 : : ScanKey orderbys, int norderbys);
1198 : : extern void btparallelrescan(IndexScanDesc scan);
1199 : : extern void btendscan(IndexScanDesc scan);
1200 : : extern void btmarkpos(IndexScanDesc scan);
1201 : : extern void btrestrpos(IndexScanDesc scan);
1202 : : extern IndexBulkDeleteResult *btbulkdelete(IndexVacuumInfo *info,
1203 : : IndexBulkDeleteResult *stats,
1204 : : IndexBulkDeleteCallback callback,
1205 : : void *callback_state);
1206 : : extern IndexBulkDeleteResult *btvacuumcleanup(IndexVacuumInfo *info,
1207 : : IndexBulkDeleteResult *stats);
1208 : : extern bool btcanreturn(Relation index, int attno);
1209 : : extern int btgettreeheight(Relation rel);
1210 : :
1211 : : extern CompareType bttranslatestrategy(StrategyNumber strategy, Oid opfamily);
1212 : : extern StrategyNumber bttranslatecmptype(CompareType cmptype, Oid opfamily);
1213 : :
1214 : : /*
1215 : : * prototypes for internal functions in nbtree.c
1216 : : */
1217 : : extern bool _bt_parallel_seize(IndexScanDesc scan, BlockNumber *next_scan_page,
1218 : : BlockNumber *last_curr_page, bool first);
1219 : : extern void _bt_parallel_release(IndexScanDesc scan,
1220 : : BlockNumber next_scan_page,
1221 : : BlockNumber curr_page);
1222 : : extern void _bt_parallel_done(IndexScanDesc scan);
1223 : : extern void _bt_parallel_primscan_schedule(IndexScanDesc scan,
1224 : : BlockNumber curr_page);
1225 : :
1226 : : /*
1227 : : * prototypes for functions in nbtdedup.c
1228 : : */
1229 : : extern void _bt_dedup_pass(Relation rel, Buffer buf, IndexTuple newitem,
1230 : : Size newitemsz, bool bottomupdedup);
1231 : : extern bool _bt_bottomupdel_pass(Relation rel, Buffer buf, Relation heapRel,
1232 : : Size newitemsz);
1233 : : extern void _bt_dedup_start_pending(BTDedupState state, IndexTuple base,
1234 : : OffsetNumber baseoff);
1235 : : extern bool _bt_dedup_save_htid(BTDedupState state, IndexTuple itup);
1236 : : extern Size _bt_dedup_finish_pending(Page newpage, BTDedupState state);
1237 : : extern IndexTuple _bt_form_posting(IndexTuple base, ItemPointer htids,
1238 : : int nhtids);
1239 : : extern void _bt_update_posting(BTVacuumPosting vacposting);
1240 : : extern IndexTuple _bt_swap_posting(IndexTuple newitem, IndexTuple oposting,
1241 : : int postingoff);
1242 : :
1243 : : /*
1244 : : * prototypes for functions in nbtinsert.c
1245 : : */
1246 : : extern bool _bt_doinsert(Relation rel, IndexTuple itup,
1247 : : IndexUniqueCheck checkUnique, bool indexUnchanged,
1248 : : Relation heapRel);
1249 : : extern void _bt_finish_split(Relation rel, Relation heaprel, Buffer lbuf,
1250 : : BTStack stack);
1251 : : extern Buffer _bt_getstackbuf(Relation rel, Relation heaprel, BTStack stack,
1252 : : BlockNumber child);
1253 : :
1254 : : /*
1255 : : * prototypes for functions in nbtsplitloc.c
1256 : : */
1257 : : extern OffsetNumber _bt_findsplitloc(Relation rel, Page origpage,
1258 : : OffsetNumber newitemoff, Size newitemsz, IndexTuple newitem,
1259 : : bool *newitemonleft);
1260 : :
1261 : : /*
1262 : : * prototypes for functions in nbtpage.c
1263 : : */
1264 : : extern void _bt_initmetapage(Page page, BlockNumber rootbknum, uint32 level,
1265 : : bool allequalimage);
1266 : : extern bool _bt_vacuum_needs_cleanup(Relation rel);
1267 : : extern void _bt_set_cleanup_info(Relation rel, BlockNumber num_delpages);
1268 : : extern void _bt_upgrademetapage(Page page);
1269 : : extern Buffer _bt_getroot(Relation rel, Relation heaprel, int access);
1270 : : extern Buffer _bt_gettrueroot(Relation rel);
1271 : : extern int _bt_getrootheight(Relation rel);
1272 : : extern void _bt_metaversion(Relation rel, bool *heapkeyspace,
1273 : : bool *allequalimage);
1274 : : extern void _bt_checkpage(Relation rel, Buffer buf);
1275 : : extern Buffer _bt_getbuf(Relation rel, BlockNumber blkno, int access);
1276 : : extern Buffer _bt_allocbuf(Relation rel, Relation heaprel);
1277 : : extern Buffer _bt_relandgetbuf(Relation rel, Buffer obuf,
1278 : : BlockNumber blkno, int access);
1279 : : extern void _bt_relbuf(Relation rel, Buffer buf);
1280 : : extern void _bt_lockbuf(Relation rel, Buffer buf, int access);
1281 : : extern void _bt_unlockbuf(Relation rel, Buffer buf);
1282 : : extern bool _bt_conditionallockbuf(Relation rel, Buffer buf);
1283 : : extern void _bt_upgradelockbufcleanup(Relation rel, Buffer buf);
1284 : : extern void _bt_pageinit(Page page, Size size);
1285 : : extern void _bt_delitems_vacuum(Relation rel, Buffer buf,
1286 : : OffsetNumber *deletable, int ndeletable,
1287 : : BTVacuumPosting *updatable, int nupdatable);
1288 : : struct TM_IndexDeleteOp; /* avoid including tableam.h here */
1289 : : extern void _bt_delitems_delete_check(Relation rel, Buffer buf,
1290 : : Relation heapRel,
1291 : : struct TM_IndexDeleteOp *delstate);
1292 : : extern void _bt_pagedel(Relation rel, Buffer leafbuf, BTVacState *vstate);
1293 : : extern void _bt_pendingfsm_init(Relation rel, BTVacState *vstate,
1294 : : bool cleanuponly);
1295 : : extern void _bt_pendingfsm_finalize(Relation rel, BTVacState *vstate);
1296 : :
1297 : : /*
1298 : : * prototypes for functions in nbtpreprocesskeys.c
1299 : : */
1300 : : extern void _bt_preprocess_keys(IndexScanDesc scan);
1301 : :
1302 : : /*
1303 : : * prototypes for functions in nbtsearch.c
1304 : : */
1305 : : extern BTStack _bt_search(Relation rel, Relation heaprel, BTScanInsert key,
1306 : : Buffer *bufP, int access);
1307 : : extern OffsetNumber _bt_binsrch_insert(Relation rel, BTInsertState insertstate);
1308 : : extern int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum);
1309 : : extern bool _bt_first(IndexScanDesc scan, ScanDirection dir);
1310 : : extern bool _bt_next(IndexScanDesc scan, ScanDirection dir);
1311 : : extern Buffer _bt_get_endpoint(Relation rel, uint32 level, bool rightmost);
1312 : :
1313 : : /*
1314 : : * prototypes for functions in nbtutils.c
1315 : : */
1316 : : extern BTScanInsert _bt_mkscankey(Relation rel, IndexTuple itup);
1317 : : extern void _bt_freestack(BTStack stack);
1318 : : extern bool _bt_start_prim_scan(IndexScanDesc scan, ScanDirection dir);
1319 : : extern int _bt_binsrch_array_skey(FmgrInfo *orderproc,
1320 : : bool cur_elem_trig, ScanDirection dir,
1321 : : Datum tupdatum, bool tupnull,
1322 : : BTArrayKeyInfo *array, ScanKey cur,
1323 : : int32 *set_elem_result);
1324 : : extern void _bt_start_array_keys(IndexScanDesc scan, ScanDirection dir);
1325 : : extern bool _bt_checkkeys(IndexScanDesc scan, BTReadPageState *pstate, bool arrayKeys,
1326 : : IndexTuple tuple, int tupnatts);
1327 : : extern bool _bt_scanbehind_checkkeys(IndexScanDesc scan, ScanDirection dir,
1328 : : IndexTuple finaltup);
1329 : : extern void _bt_set_startikey(IndexScanDesc scan, BTReadPageState *pstate);
1330 : : extern void _bt_killitems(IndexScanDesc scan);
1331 : : extern BTCycleId _bt_vacuum_cycleid(Relation rel);
1332 : : extern BTCycleId _bt_start_vacuum(Relation rel);
1333 : : extern void _bt_end_vacuum(Relation rel);
1334 : : extern void _bt_end_vacuum_callback(int code, Datum arg);
1335 : : extern Size BTreeShmemSize(void);
1336 : : extern void BTreeShmemInit(void);
1337 : : extern bytea *btoptions(Datum reloptions, bool validate);
1338 : : extern bool btproperty(Oid index_oid, int attno,
1339 : : IndexAMProperty prop, const char *propname,
1340 : : bool *res, bool *isnull);
1341 : : extern char *btbuildphasename(int64 phasenum);
1342 : : extern IndexTuple _bt_truncate(Relation rel, IndexTuple lastleft,
1343 : : IndexTuple firstright, BTScanInsert itup_key);
1344 : : extern int _bt_keep_natts_fast(Relation rel, IndexTuple lastleft,
1345 : : IndexTuple firstright);
1346 : : extern bool _bt_check_natts(Relation rel, bool heapkeyspace, Page page,
1347 : : OffsetNumber offnum);
1348 : : extern void _bt_check_third_page(Relation rel, Relation heap,
1349 : : bool needheaptidspace, Page page, IndexTuple newtup);
1350 : : extern bool _bt_allequalimage(Relation rel, bool debugmessage);
1351 : :
1352 : : /*
1353 : : * prototypes for functions in nbtvalidate.c
1354 : : */
1355 : : extern bool btvalidate(Oid opclassoid);
1356 : : extern void btadjustmembers(Oid opfamilyoid,
1357 : : Oid opclassoid,
1358 : : List *operators,
1359 : : List *functions);
1360 : :
1361 : : /*
1362 : : * prototypes for functions in nbtsort.c
1363 : : */
1364 : : extern IndexBuildResult *btbuild(Relation heap, Relation index,
1365 : : struct IndexInfo *indexInfo);
1366 : : extern void _bt_parallel_build_main(dsm_segment *seg, shm_toc *toc);
1367 : :
1368 : : #endif /* NBTREE_H */
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