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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/shm_toc.h"
26 : : #include "utils/skipsupport.h"
27 : :
28 : : /* There's room for a 16-bit vacuum cycle ID in BTPageOpaqueData */
29 : : typedef uint16 BTCycleId;
30 : :
31 : : /*
32 : : * BTPageOpaqueData -- At the end of every page, we store a pointer
33 : : * to both siblings in the tree. This is used to do forward/backward
34 : : * index scans. The next-page link is also critical for recovery when
35 : : * a search has navigated to the wrong page due to concurrent page splits
36 : : * or deletions; see src/backend/access/nbtree/README for more info.
37 : : *
38 : : * In addition, we store the page's btree level (counting upwards from
39 : : * zero at a leaf page) as well as some flag bits indicating the page type
40 : : * and status. If the page is deleted, a BTDeletedPageData struct is stored
41 : : * in the page's tuple area, while a standard BTPageOpaqueData struct is
42 : : * stored in the page special area.
43 : : *
44 : : * We also store a "vacuum cycle ID". When a page is split while VACUUM is
45 : : * processing the index, a nonzero value associated with the VACUUM run is
46 : : * stored into both halves of the split page. (If VACUUM is not running,
47 : : * both pages receive zero cycleids.) This allows VACUUM to detect whether
48 : : * a page was split since it started, with a small probability of false match
49 : : * if the page was last split some exact multiple of MAX_BT_CYCLE_ID VACUUMs
50 : : * ago. Also, during a split, the BTP_SPLIT_END flag is cleared in the left
51 : : * (original) page, and set in the right page, but only if the next page
52 : : * to its right has a different cycleid.
53 : : *
54 : : * NOTE: the BTP_LEAF flag bit is redundant since level==0 could be tested
55 : : * instead.
56 : : *
57 : : * NOTE: the btpo_level field used to be a union type in order to allow
58 : : * deleted pages to store a 32-bit safexid in the same field. We now store
59 : : * 64-bit/full safexid values using BTDeletedPageData instead.
60 : : */
61 : :
62 : : typedef struct BTPageOpaqueData
63 : : {
64 : : BlockNumber btpo_prev; /* left sibling, or P_NONE if leftmost */
65 : : BlockNumber btpo_next; /* right sibling, or P_NONE if rightmost */
66 : : uint32 btpo_level; /* tree level --- zero for leaf pages */
67 : : uint16 btpo_flags; /* flag bits, see below */
68 : : BTCycleId btpo_cycleid; /* vacuum cycle ID of latest split */
69 : : } BTPageOpaqueData;
70 : :
71 : : typedef BTPageOpaqueData *BTPageOpaque;
72 : :
73 : : #define BTPageGetOpaque(page) ((BTPageOpaque) PageGetSpecialPointer(page))
74 : :
75 : : /* Bits defined in btpo_flags */
76 : : #define BTP_LEAF (1 << 0) /* leaf page, i.e. not internal page */
77 : : #define BTP_ROOT (1 << 1) /* root page (has no parent) */
78 : : #define BTP_DELETED (1 << 2) /* page has been deleted from tree */
79 : : #define BTP_META (1 << 3) /* meta-page */
80 : : #define BTP_HALF_DEAD (1 << 4) /* empty, but still in tree */
81 : : #define BTP_SPLIT_END (1 << 5) /* rightmost page of split group */
82 : : #define BTP_HAS_GARBAGE (1 << 6) /* page has LP_DEAD tuples (deprecated) */
83 : : #define BTP_INCOMPLETE_SPLIT (1 << 7) /* right sibling's downlink is missing */
84 : : #define BTP_HAS_FULLXID (1 << 8) /* contains BTDeletedPageData */
85 : :
86 : : /*
87 : : * The max allowed value of a cycle ID is a bit less than 64K. This is
88 : : * for convenience of pg_filedump and similar utilities: we want to use
89 : : * the last 2 bytes of special space as an index type indicator, and
90 : : * restricting cycle ID lets btree use that space for vacuum cycle IDs
91 : : * while still allowing index type to be identified.
92 : : */
93 : : #define MAX_BT_CYCLE_ID 0xFF7F
94 : :
95 : :
96 : : /*
97 : : * The Meta page is always the first page in the btree index.
98 : : * Its primary purpose is to point to the location of the btree root page.
99 : : * We also point to the "fast" root, which is the current effective root;
100 : : * see README for discussion.
101 : : */
102 : :
103 : : typedef struct BTMetaPageData
104 : : {
105 : : uint32 btm_magic; /* should contain BTREE_MAGIC */
106 : : uint32 btm_version; /* nbtree version (always <= BTREE_VERSION) */
107 : : BlockNumber btm_root; /* current root location */
108 : : uint32 btm_level; /* tree level of the root page */
109 : : BlockNumber btm_fastroot; /* current "fast" root location */
110 : : uint32 btm_fastlevel; /* tree level of the "fast" root page */
111 : : /* remaining fields only valid when btm_version >= BTREE_NOVAC_VERSION */
112 : :
113 : : /* number of deleted, non-recyclable pages during last cleanup */
114 : : uint32 btm_last_cleanup_num_delpages;
115 : : /* number of heap tuples during last cleanup (deprecated) */
116 : : float8 btm_last_cleanup_num_heap_tuples;
117 : :
118 : : bool btm_allequalimage; /* are all columns "equalimage"? */
119 : : } BTMetaPageData;
120 : :
121 : : #define BTPageGetMeta(p) \
122 : : ((BTMetaPageData *) PageGetContents(p))
123 : :
124 : : /*
125 : : * The current Btree version is 4. That's what you'll get when you create
126 : : * a new index.
127 : : *
128 : : * Btree version 3 was used in PostgreSQL v11. It is mostly the same as
129 : : * version 4, but heap TIDs were not part of the keyspace. Index tuples
130 : : * with duplicate keys could be stored in any order. We continue to
131 : : * support reading and writing Btree versions 2 and 3, so that they don't
132 : : * need to be immediately re-indexed at pg_upgrade. In order to get the
133 : : * new heapkeyspace semantics, however, a REINDEX is needed.
134 : : *
135 : : * Deduplication is safe to use when the btm_allequalimage field is set to
136 : : * true. It's safe to read the btm_allequalimage field on version 3, but
137 : : * only version 4 indexes make use of deduplication. Even version 4
138 : : * indexes created on PostgreSQL v12 will need a REINDEX to make use of
139 : : * deduplication, though, since there is no other way to set
140 : : * btm_allequalimage to true (pg_upgrade hasn't been taught to set the
141 : : * metapage field).
142 : : *
143 : : * Btree version 2 is mostly the same as version 3. There are two new
144 : : * fields in the metapage that were introduced in version 3. A version 2
145 : : * metapage will be automatically upgraded to version 3 on the first
146 : : * insert to it. INCLUDE indexes cannot use version 2.
147 : : */
148 : : #define BTREE_METAPAGE 0 /* first page is meta */
149 : : #define BTREE_MAGIC 0x053162 /* magic number in metapage */
150 : : #define BTREE_VERSION 4 /* current version number */
151 : : #define BTREE_MIN_VERSION 2 /* minimum supported version */
152 : : #define BTREE_NOVAC_VERSION 3 /* version with all meta fields set */
153 : :
154 : : /*
155 : : * Maximum size of a btree index entry, including its tuple header.
156 : : *
157 : : * We actually need to be able to fit three items on every page,
158 : : * so restrict any one item to 1/3 the per-page available space.
159 : : *
160 : : * There are rare cases where _bt_truncate() will need to enlarge
161 : : * a heap index tuple to make space for a tiebreaker heap TID
162 : : * attribute, which we account for here.
163 : : */
164 : : #define BTMaxItemSize \
165 : : (MAXALIGN_DOWN((BLCKSZ - \
166 : : MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
167 : : MAXALIGN(sizeof(BTPageOpaqueData))) / 3) - \
168 : : MAXALIGN(sizeof(ItemPointerData)))
169 : : #define BTMaxItemSizeNoHeapTid \
170 : : MAXALIGN_DOWN((BLCKSZ - \
171 : : MAXALIGN(SizeOfPageHeaderData + 3*sizeof(ItemIdData)) - \
172 : : MAXALIGN(sizeof(BTPageOpaqueData))) / 3)
173 : :
174 : : /*
175 : : * MaxTIDsPerBTreePage is an upper bound on the number of heap TIDs tuples
176 : : * that may be stored on a btree leaf page. It is used to size the
177 : : * per-page temporary buffers.
178 : : *
179 : : * Note: we don't bother considering per-tuple overheads here to keep
180 : : * things simple (value is based on how many elements a single array of
181 : : * heap TIDs must have to fill the space between the page header and
182 : : * special area). The value is slightly higher (i.e. more conservative)
183 : : * than necessary as a result, which is considered acceptable.
184 : : */
185 : : #define MaxTIDsPerBTreePage \
186 : : (int) ((BLCKSZ - SizeOfPageHeaderData - sizeof(BTPageOpaqueData)) / \
187 : : sizeof(ItemPointerData))
188 : :
189 : : /*
190 : : * The leaf-page fillfactor defaults to 90% but is user-adjustable.
191 : : * For pages above the leaf level, we use a fixed 70% fillfactor.
192 : : * The fillfactor is applied during index build and when splitting
193 : : * a rightmost page; when splitting non-rightmost pages we try to
194 : : * divide the data equally. When splitting a page that's entirely
195 : : * filled with a single value (duplicates), the effective leaf-page
196 : : * fillfactor is 96%, regardless of whether the page is a rightmost
197 : : * page.
198 : : */
199 : : #define BTREE_MIN_FILLFACTOR 10
200 : : #define BTREE_DEFAULT_FILLFACTOR 90
201 : : #define BTREE_NONLEAF_FILLFACTOR 70
202 : : #define BTREE_SINGLEVAL_FILLFACTOR 96
203 : :
204 : : /*
205 : : * In general, the btree code tries to localize its knowledge about
206 : : * page layout to a couple of routines. However, we need a special
207 : : * value to indicate "no page number" in those places where we expect
208 : : * page numbers. We can use zero for this because we never need to
209 : : * make a pointer to the metadata page.
210 : : */
211 : :
212 : : #define P_NONE 0
213 : :
214 : : /*
215 : : * Macros to test whether a page is leftmost or rightmost on its tree level,
216 : : * as well as other state info kept in the opaque data.
217 : : */
218 : : #define P_LEFTMOST(opaque) ((opaque)->btpo_prev == P_NONE)
219 : : #define P_RIGHTMOST(opaque) ((opaque)->btpo_next == P_NONE)
220 : : #define P_ISLEAF(opaque) (((opaque)->btpo_flags & BTP_LEAF) != 0)
221 : : #define P_ISROOT(opaque) (((opaque)->btpo_flags & BTP_ROOT) != 0)
222 : : #define P_ISDELETED(opaque) (((opaque)->btpo_flags & BTP_DELETED) != 0)
223 : : #define P_ISMETA(opaque) (((opaque)->btpo_flags & BTP_META) != 0)
224 : : #define P_ISHALFDEAD(opaque) (((opaque)->btpo_flags & BTP_HALF_DEAD) != 0)
225 : : #define P_IGNORE(opaque) (((opaque)->btpo_flags & (BTP_DELETED|BTP_HALF_DEAD)) != 0)
226 : : #define P_HAS_GARBAGE(opaque) (((opaque)->btpo_flags & BTP_HAS_GARBAGE) != 0)
227 : : #define P_INCOMPLETE_SPLIT(opaque) (((opaque)->btpo_flags & BTP_INCOMPLETE_SPLIT) != 0)
228 : : #define P_HAS_FULLXID(opaque) (((opaque)->btpo_flags & BTP_HAS_FULLXID) != 0)
229 : :
230 : : /*
231 : : * BTDeletedPageData is the page contents of a deleted page
232 : : */
233 : : typedef struct BTDeletedPageData
234 : : {
235 : : FullTransactionId safexid; /* See BTPageIsRecyclable() */
236 : : } BTDeletedPageData;
237 : :
238 : : static inline void
1655 pg@bowt.ie 239 :CBC 3705 : BTPageSetDeleted(Page page, FullTransactionId safexid)
240 : : {
241 : : BTPageOpaque opaque;
242 : : PageHeader header;
243 : : BTDeletedPageData *contents;
244 : :
1254 michael@paquier.xyz 245 : 3705 : opaque = BTPageGetOpaque(page);
1655 pg@bowt.ie 246 : 3705 : header = ((PageHeader) page);
247 : :
248 : 3705 : opaque->btpo_flags &= ~BTP_HALF_DEAD;
249 : 3705 : opaque->btpo_flags |= BTP_DELETED | BTP_HAS_FULLXID;
250 : 3705 : header->pd_lower = MAXALIGN(SizeOfPageHeaderData) +
251 : : sizeof(BTDeletedPageData);
252 : 3705 : header->pd_upper = header->pd_special;
253 : :
254 : : /* Set safexid in deleted page */
255 : 3705 : contents = ((BTDeletedPageData *) PageGetContents(page));
256 : 3705 : contents->safexid = safexid;
257 : 3705 : }
258 : :
259 : : static inline FullTransactionId
260 : 2383 : BTPageGetDeleteXid(Page page)
261 : : {
262 : : BTPageOpaque opaque;
263 : : BTDeletedPageData *contents;
264 : :
265 : : /* We only expect to be called with a deleted page */
266 [ - + ]: 2383 : Assert(!PageIsNew(page));
1254 michael@paquier.xyz 267 : 2383 : opaque = BTPageGetOpaque(page);
1655 pg@bowt.ie 268 [ - + ]: 2383 : Assert(P_ISDELETED(opaque));
269 : :
270 : : /* pg_upgrade'd deleted page -- must be safe to recycle now */
271 [ - + ]: 2383 : if (!P_HAS_FULLXID(opaque))
1655 pg@bowt.ie 272 :UBC 0 : return FirstNormalFullTransactionId;
273 : :
274 : : /* Get safexid from deleted page */
1655 pg@bowt.ie 275 :CBC 2383 : contents = ((BTDeletedPageData *) PageGetContents(page));
276 : 2383 : return contents->safexid;
277 : : }
278 : :
279 : : /*
280 : : * Is an existing page recyclable?
281 : : *
282 : : * This exists to centralize the policy on which deleted pages are now safe to
283 : : * re-use. However, _bt_pendingfsm_finalize() duplicates some of the same
284 : : * logic because it doesn't work directly with pages -- keep the two in sync.
285 : : *
286 : : * Note: PageIsNew() pages are always safe to recycle, but we can't deal with
287 : : * them here (caller is responsible for that case themselves). Caller might
288 : : * well need special handling for new pages anyway.
289 : : */
290 : : static inline bool
887 291 : 15489 : BTPageIsRecyclable(Page page, Relation heaprel)
292 : : {
293 : : BTPageOpaque opaque;
294 : :
1655 295 [ - + ]: 15489 : Assert(!PageIsNew(page));
819 296 [ - + ]: 15489 : Assert(heaprel != NULL);
297 : :
298 : : /* Recycling okay iff page is deleted and safexid is old enough */
1254 michael@paquier.xyz 299 : 15489 : opaque = BTPageGetOpaque(page);
1655 pg@bowt.ie 300 [ + + ]: 15489 : if (P_ISDELETED(opaque))
301 : : {
819 302 : 2039 : FullTransactionId safexid = BTPageGetDeleteXid(page);
303 : :
304 : : /*
305 : : * The page was deleted, but when? If it was just deleted, a scan
306 : : * might have seen the downlink to it, and will read the page later.
307 : : * As long as that can happen, we must keep the deleted page around as
308 : : * a tombstone.
309 : : *
310 : : * For that check if the deletion XID could still be visible to
311 : : * anyone. If not, then no scan that's still in progress could have
312 : : * seen its downlink, and we can recycle it.
313 : : */
314 : 2039 : return GlobalVisCheckRemovableFullXid(heaprel, safexid);
315 : : }
316 : :
1655 317 : 13450 : return false;
318 : : }
319 : :
320 : : /*
321 : : * BTVacState and BTPendingFSM are private nbtree.c state used during VACUUM.
322 : : * They are exported for use by page deletion related code in nbtpage.c.
323 : : */
324 : : typedef struct BTPendingFSM
325 : : {
326 : : BlockNumber target; /* Page deleted by current VACUUM */
327 : : FullTransactionId safexid; /* Page's BTDeletedPageData.safexid */
328 : : } BTPendingFSM;
329 : :
330 : : typedef struct BTVacState
331 : : {
332 : : IndexVacuumInfo *info;
333 : : IndexBulkDeleteResult *stats;
334 : : IndexBulkDeleteCallback callback;
335 : : void *callback_state;
336 : : BTCycleId cycleid;
337 : : MemoryContext pagedelcontext;
338 : :
339 : : /*
340 : : * _bt_pendingfsm_finalize() state
341 : : */
342 : : int bufsize; /* pendingpages space (in # elements) */
343 : : int maxbufsize; /* max bufsize that respects work_mem */
344 : : BTPendingFSM *pendingpages; /* One entry per newly deleted page */
345 : : int npendingpages; /* current # valid pendingpages */
346 : : } BTVacState;
347 : :
348 : : /*
349 : : * Lehman and Yao's algorithm requires a ``high key'' on every non-rightmost
350 : : * page. The high key is not a tuple that is used to visit the heap. It is
351 : : * a pivot tuple (see "Notes on B-Tree tuple format" below for definition).
352 : : * The high key on a page is required to be greater than or equal to any
353 : : * other key that appears on the page. If we find ourselves trying to
354 : : * insert a key that is strictly > high key, we know we need to move right
355 : : * (this should only happen if the page was split since we examined the
356 : : * parent page).
357 : : *
358 : : * Our insertion algorithm guarantees that we can use the initial least key
359 : : * on our right sibling as the high key. Once a page is created, its high
360 : : * key changes only if the page is split.
361 : : *
362 : : * On a non-rightmost page, the high key lives in item 1 and data items
363 : : * start in item 2. Rightmost pages have no high key, so we store data
364 : : * items beginning in item 1.
365 : : */
366 : :
367 : : #define P_HIKEY ((OffsetNumber) 1)
368 : : #define P_FIRSTKEY ((OffsetNumber) 2)
369 : : #define P_FIRSTDATAKEY(opaque) (P_RIGHTMOST(opaque) ? P_HIKEY : P_FIRSTKEY)
370 : :
371 : : /*
372 : : * Notes on B-Tree tuple format, and key and non-key attributes:
373 : : *
374 : : * INCLUDE B-Tree indexes have non-key attributes. These are extra
375 : : * attributes that may be returned by index-only scans, but do not influence
376 : : * the order of items in the index (formally, non-key attributes are not
377 : : * considered to be part of the key space). Non-key attributes are only
378 : : * present in leaf index tuples whose item pointers actually point to heap
379 : : * tuples (non-pivot tuples). _bt_check_natts() enforces the rules
380 : : * described here.
381 : : *
382 : : * Non-pivot tuple format (plain/non-posting variant):
383 : : *
384 : : * t_tid | t_info | key values | INCLUDE columns, if any
385 : : *
386 : : * t_tid points to the heap TID, which is a tiebreaker key column as of
387 : : * BTREE_VERSION 4.
388 : : *
389 : : * Non-pivot tuples complement pivot tuples, which only have key columns.
390 : : * The sole purpose of pivot tuples is to represent how the key space is
391 : : * separated. In general, any B-Tree index that has more than one level
392 : : * (i.e. any index that does not just consist of a metapage and a single
393 : : * leaf root page) must have some number of pivot tuples, since pivot
394 : : * tuples are used for traversing the tree. Suffix truncation can omit
395 : : * trailing key columns when a new pivot is formed, which makes minus
396 : : * infinity their logical value. Since BTREE_VERSION 4 indexes treat heap
397 : : * TID as a trailing key column that ensures that all index tuples are
398 : : * physically unique, it is necessary to represent heap TID as a trailing
399 : : * key column in pivot tuples, though very often this can be truncated
400 : : * away, just like any other key column. (Actually, the heap TID is
401 : : * omitted rather than truncated, since its representation is different to
402 : : * the non-pivot representation.)
403 : : *
404 : : * Pivot tuple format:
405 : : *
406 : : * t_tid | t_info | key values | [heap TID]
407 : : *
408 : : * We store the number of columns present inside pivot tuples by abusing
409 : : * their t_tid offset field, since pivot tuples never need to store a real
410 : : * offset (pivot tuples generally store a downlink in t_tid, though). The
411 : : * offset field only stores the number of columns/attributes when the
412 : : * INDEX_ALT_TID_MASK bit is set, which doesn't count the trailing heap
413 : : * TID column sometimes stored in pivot tuples -- that's represented by
414 : : * the presence of BT_PIVOT_HEAP_TID_ATTR. The INDEX_ALT_TID_MASK bit in
415 : : * t_info is always set on BTREE_VERSION 4 pivot tuples, since
416 : : * BTreeTupleIsPivot() must work reliably on heapkeyspace versions.
417 : : *
418 : : * In version 2 or version 3 (!heapkeyspace) indexes, INDEX_ALT_TID_MASK
419 : : * might not be set in pivot tuples. BTreeTupleIsPivot() won't work
420 : : * reliably as a result. The number of columns stored is implicitly the
421 : : * same as the number of columns in the index, just like any non-pivot
422 : : * tuple. (The number of columns stored should not vary, since suffix
423 : : * truncation of key columns is unsafe within any !heapkeyspace index.)
424 : : *
425 : : * The 12 least significant bits from t_tid's offset number are used to
426 : : * represent the number of key columns within a pivot tuple. This leaves 4
427 : : * status bits (BT_STATUS_OFFSET_MASK bits), which are shared by all tuples
428 : : * that have the INDEX_ALT_TID_MASK bit set (set in t_info) to store basic
429 : : * tuple metadata. BTreeTupleIsPivot() and BTreeTupleIsPosting() use the
430 : : * BT_STATUS_OFFSET_MASK bits.
431 : : *
432 : : * Sometimes non-pivot tuples also use a representation that repurposes
433 : : * t_tid to store metadata rather than a TID. PostgreSQL v13 introduced a
434 : : * new non-pivot tuple format to support deduplication: posting list
435 : : * tuples. Deduplication merges together multiple equal non-pivot tuples
436 : : * into a logically equivalent, space efficient representation. A posting
437 : : * list is an array of ItemPointerData elements. Non-pivot tuples are
438 : : * merged together to form posting list tuples lazily, at the point where
439 : : * we'd otherwise have to split a leaf page.
440 : : *
441 : : * Posting tuple format (alternative non-pivot tuple representation):
442 : : *
443 : : * t_tid | t_info | key values | posting list (TID array)
444 : : *
445 : : * Posting list tuples are recognized as such by having the
446 : : * INDEX_ALT_TID_MASK status bit set in t_info and the BT_IS_POSTING status
447 : : * bit set in t_tid's offset number. These flags redefine the content of
448 : : * the posting tuple's t_tid to store the location of the posting list
449 : : * (instead of a block number), as well as the total number of heap TIDs
450 : : * present in the tuple (instead of a real offset number).
451 : : *
452 : : * The 12 least significant bits from t_tid's offset number are used to
453 : : * represent the number of heap TIDs present in the tuple, leaving 4 status
454 : : * bits (the BT_STATUS_OFFSET_MASK bits). Like any non-pivot tuple, the
455 : : * number of columns stored is always implicitly the total number in the
456 : : * index (in practice there can never be non-key columns stored, since
457 : : * deduplication is not supported with INCLUDE indexes).
458 : : */
459 : : #define INDEX_ALT_TID_MASK INDEX_AM_RESERVED_BIT
460 : :
461 : : /* Item pointer offset bit masks */
462 : : #define BT_OFFSET_MASK 0x0FFF
463 : : #define BT_STATUS_OFFSET_MASK 0xF000
464 : : /* BT_STATUS_OFFSET_MASK status bits */
465 : : #define BT_PIVOT_HEAP_TID_ATTR 0x1000
466 : : #define BT_IS_POSTING 0x2000
467 : :
468 : : /*
469 : : * Mask allocated for number of keys in index tuple must be able to fit
470 : : * maximum possible number of index attributes
471 : : */
472 : : StaticAssertDecl(BT_OFFSET_MASK >= INDEX_MAX_KEYS,
473 : : "BT_OFFSET_MASK can't fit INDEX_MAX_KEYS");
474 : :
475 : : /*
476 : : * Note: BTreeTupleIsPivot() can have false negatives (but not false
477 : : * positives) when used with !heapkeyspace indexes
478 : : */
479 : : static inline bool
2019 480 : 556921049 : BTreeTupleIsPivot(IndexTuple itup)
481 : : {
482 [ + + ]: 556921049 : if ((itup->t_info & INDEX_ALT_TID_MASK) == 0)
483 : 375987221 : return false;
484 : : /* absence of BT_IS_POSTING in offset number indicates pivot tuple */
485 [ + + ]: 180933828 : if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) & BT_IS_POSTING) != 0)
486 : 7440197 : return false;
487 : :
488 : 173493631 : return true;
489 : : }
490 : :
491 : : static inline bool
492 : 432400571 : BTreeTupleIsPosting(IndexTuple itup)
493 : : {
494 [ + + ]: 432400571 : if ((itup->t_info & INDEX_ALT_TID_MASK) == 0)
495 : 264511402 : return false;
496 : : /* presence of BT_IS_POSTING in offset number indicates posting tuple */
497 [ + + ]: 167889169 : if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) & BT_IS_POSTING) == 0)
498 : 126753103 : return false;
499 : :
500 : 41136066 : return true;
501 : : }
502 : :
503 : : static inline void
1963 504 : 228945 : BTreeTupleSetPosting(IndexTuple itup, uint16 nhtids, int postingoffset)
505 : : {
506 [ - + ]: 228945 : Assert(nhtids > 1);
507 [ - + ]: 228945 : Assert((nhtids & BT_STATUS_OFFSET_MASK) == 0);
2014 508 [ - + ]: 228945 : Assert((size_t) postingoffset == MAXALIGN(postingoffset));
2019 509 [ - + ]: 228945 : Assert(postingoffset < INDEX_SIZE_MASK);
1963 510 [ - + ]: 228945 : Assert(!BTreeTupleIsPivot(itup));
511 : :
2019 512 : 228945 : itup->t_info |= INDEX_ALT_TID_MASK;
513 : 228945 : ItemPointerSetOffsetNumber(&itup->t_tid, (nhtids | BT_IS_POSTING));
514 : 228945 : ItemPointerSetBlockNumber(&itup->t_tid, postingoffset);
515 : 228945 : }
516 : :
517 : : static inline uint16
518 : 14945004 : BTreeTupleGetNPosting(IndexTuple posting)
519 : : {
520 : : OffsetNumber existing;
521 : :
522 [ - + ]: 14945004 : Assert(BTreeTupleIsPosting(posting));
523 : :
524 : 14945004 : existing = ItemPointerGetOffsetNumberNoCheck(&posting->t_tid);
525 : 14945004 : return (existing & BT_OFFSET_MASK);
526 : : }
527 : :
528 : : static inline uint32
529 : 16576879 : BTreeTupleGetPostingOffset(IndexTuple posting)
530 : : {
531 [ - + ]: 16576879 : Assert(BTreeTupleIsPosting(posting));
532 : :
533 : 16576879 : return ItemPointerGetBlockNumberNoCheck(&posting->t_tid);
534 : : }
535 : :
536 : : static inline ItemPointer
537 : 15395184 : BTreeTupleGetPosting(IndexTuple posting)
538 : : {
539 : 30790368 : return (ItemPointer) ((char *) posting +
540 : 15395184 : BTreeTupleGetPostingOffset(posting));
541 : : }
542 : :
543 : : static inline ItemPointer
544 : 13455872 : BTreeTupleGetPostingN(IndexTuple posting, int n)
545 : : {
546 : 13455872 : return BTreeTupleGetPosting(posting) + n;
547 : : }
548 : :
549 : : /*
550 : : * Get/set downlink block number in pivot tuple.
551 : : *
552 : : * Note: Cannot assert that tuple is a pivot tuple. If we did so then
553 : : * !heapkeyspace indexes would exhibit false positive assertion failures.
554 : : */
555 : : static inline BlockNumber
556 : 8762179 : BTreeTupleGetDownLink(IndexTuple pivot)
557 : : {
558 : 8762179 : return ItemPointerGetBlockNumberNoCheck(&pivot->t_tid);
559 : : }
560 : :
561 : : static inline void
562 : 37002 : BTreeTupleSetDownLink(IndexTuple pivot, BlockNumber blkno)
563 : : {
564 : 37002 : ItemPointerSetBlockNumber(&pivot->t_tid, blkno);
565 : 37002 : }
566 : :
567 : : /*
568 : : * Get number of attributes within tuple.
569 : : *
570 : : * Note that this does not include an implicit tiebreaker heap TID
571 : : * attribute, if any. Note also that the number of key attributes must be
572 : : * explicitly represented in all heapkeyspace pivot tuples.
573 : : *
574 : : * Note: This is defined as a macro rather than an inline function to
575 : : * avoid including rel.h.
576 : : */
577 : : #define BTreeTupleGetNAtts(itup, rel) \
578 : : ( \
579 : : (BTreeTupleIsPivot(itup)) ? \
580 : : ( \
581 : : ItemPointerGetOffsetNumberNoCheck(&(itup)->t_tid) & BT_OFFSET_MASK \
582 : : ) \
583 : : : \
584 : : IndexRelationGetNumberOfAttributes(rel) \
585 : : )
586 : :
587 : : /*
588 : : * Set number of key attributes in tuple.
589 : : *
590 : : * The heap TID tiebreaker attribute bit may also be set here, indicating that
591 : : * a heap TID value will be stored at the end of the tuple (i.e. using the
592 : : * special pivot tuple representation).
593 : : */
594 : : static inline void
1978 595 : 43496 : BTreeTupleSetNAtts(IndexTuple itup, uint16 nkeyatts, bool heaptid)
596 : : {
597 [ - + ]: 43496 : Assert(nkeyatts <= INDEX_MAX_KEYS);
1963 598 [ - + ]: 43496 : Assert((nkeyatts & BT_STATUS_OFFSET_MASK) == 0);
1978 599 [ + + - + ]: 43496 : Assert(!heaptid || nkeyatts > 0);
600 [ + + - + ]: 43496 : Assert(!BTreeTupleIsPivot(itup) || nkeyatts == 0);
601 : :
2019 602 : 43496 : itup->t_info |= INDEX_ALT_TID_MASK;
603 : :
1978 604 [ + + ]: 43496 : if (heaptid)
605 : 547 : nkeyatts |= BT_PIVOT_HEAP_TID_ATTR;
606 : :
607 : : /* BT_IS_POSTING bit is deliberately unset here */
608 : 43496 : ItemPointerSetOffsetNumber(&itup->t_tid, nkeyatts);
609 [ - + ]: 43496 : Assert(BTreeTupleIsPivot(itup));
2019 610 : 43496 : }
611 : :
612 : : /*
613 : : * Get/set leaf page's "top parent" link from its high key. Used during page
614 : : * deletion.
615 : : *
616 : : * Note: Cannot assert that tuple is a pivot tuple. If we did so then
617 : : * !heapkeyspace indexes would exhibit false positive assertion failures.
618 : : */
619 : : static inline BlockNumber
620 : 2998 : BTreeTupleGetTopParent(IndexTuple leafhikey)
621 : : {
622 : 2998 : return ItemPointerGetBlockNumberNoCheck(&leafhikey->t_tid);
623 : : }
624 : :
625 : : static inline void
626 : 3706 : BTreeTupleSetTopParent(IndexTuple leafhikey, BlockNumber blkno)
627 : : {
628 : 3706 : ItemPointerSetBlockNumber(&leafhikey->t_tid, blkno);
1978 629 : 3706 : BTreeTupleSetNAtts(leafhikey, 0, false);
2019 630 : 3706 : }
631 : :
632 : : /*
633 : : * Get tiebreaker heap TID attribute, if any.
634 : : *
635 : : * This returns the first/lowest heap TID in the case of a posting list tuple.
636 : : */
637 : : static inline ItemPointer
638 : 57986235 : BTreeTupleGetHeapTID(IndexTuple itup)
639 : : {
640 [ + + ]: 57986235 : if (BTreeTupleIsPivot(itup))
641 : : {
642 : : /* Pivot tuple heap TID representation? */
643 [ + + ]: 40884900 : if ((ItemPointerGetOffsetNumberNoCheck(&itup->t_tid) &
644 : : BT_PIVOT_HEAP_TID_ATTR) != 0)
645 : 372769 : return (ItemPointer) ((char *) itup + IndexTupleSize(itup) -
646 : : sizeof(ItemPointerData));
647 : :
648 : : /* Heap TID attribute was truncated */
649 : 40512131 : return NULL;
650 : : }
651 [ + + ]: 17101335 : else if (BTreeTupleIsPosting(itup))
652 : 672048 : return BTreeTupleGetPosting(itup);
653 : :
654 : 16429287 : return &itup->t_tid;
655 : : }
656 : :
657 : : /*
658 : : * Get maximum heap TID attribute, which could be the only TID in the case of
659 : : * a non-pivot tuple that does not have a posting list.
660 : : *
661 : : * Works with non-pivot tuples only.
662 : : */
663 : : static inline ItemPointer
664 : 154109 : BTreeTupleGetMaxHeapTID(IndexTuple itup)
665 : : {
666 [ - + ]: 154109 : Assert(!BTreeTupleIsPivot(itup));
667 : :
668 [ + + ]: 154109 : if (BTreeTupleIsPosting(itup))
669 : : {
670 : 153585 : uint16 nposting = BTreeTupleGetNPosting(itup);
671 : :
672 : 153585 : return BTreeTupleGetPostingN(itup, nposting - 1);
673 : : }
674 : :
675 : 524 : return &itup->t_tid;
676 : : }
677 : :
678 : : /*
679 : : * Operator strategy numbers for B-tree have been moved to access/stratnum.h,
680 : : * because many places need to use them in ScanKeyInit() calls.
681 : : *
682 : : * The strategy numbers are chosen so that we can commute them by
683 : : * subtraction, thus:
684 : : */
685 : : #define BTCommuteStrategyNumber(strat) (BTMaxStrategyNumber + 1 - (strat))
686 : :
687 : : /*
688 : : * When a new operator class is declared, we require that the user
689 : : * supply us with an amproc procedure (BTORDER_PROC) for determining
690 : : * whether, for two keys a and b, a < b, a = b, or a > b. This routine
691 : : * must return < 0, 0, > 0, respectively, in these three cases.
692 : : *
693 : : * To facilitate accelerated sorting, an operator class may choose to
694 : : * offer a second procedure (BTSORTSUPPORT_PROC). For full details, see
695 : : * src/include/utils/sortsupport.h.
696 : : *
697 : : * To support window frames defined by "RANGE offset PRECEDING/FOLLOWING",
698 : : * an operator class may choose to offer a third amproc procedure
699 : : * (BTINRANGE_PROC), independently of whether it offers sortsupport.
700 : : * For full details, see doc/src/sgml/btree.sgml.
701 : : *
702 : : * To facilitate B-Tree deduplication, an operator class may choose to
703 : : * offer a forth amproc procedure (BTEQUALIMAGE_PROC). For full details,
704 : : * see doc/src/sgml/btree.sgml.
705 : : *
706 : : * An operator class may choose to offer a fifth amproc procedure
707 : : * (BTOPTIONS_PROC). These procedures define a set of user-visible
708 : : * parameters that can be used to control operator class behavior. None of
709 : : * the built-in B-Tree operator classes currently register an "options" proc.
710 : : *
711 : : * To facilitate more efficient B-Tree skip scans, an operator class may
712 : : * choose to offer a sixth amproc procedure (BTSKIPSUPPORT_PROC). For full
713 : : * details, see src/include/utils/skipsupport.h.
714 : : */
715 : :
716 : : #define BTORDER_PROC 1
717 : : #define BTSORTSUPPORT_PROC 2
718 : : #define BTINRANGE_PROC 3
719 : : #define BTEQUALIMAGE_PROC 4
720 : : #define BTOPTIONS_PROC 5
721 : : #define BTSKIPSUPPORT_PROC 6
722 : : #define BTNProcs 6
723 : :
724 : : /*
725 : : * We need to be able to tell the difference between read and write
726 : : * requests for pages, in order to do locking correctly.
727 : : */
728 : :
729 : : #define BT_READ BUFFER_LOCK_SHARE
730 : : #define BT_WRITE BUFFER_LOCK_EXCLUSIVE
731 : :
732 : : /*
733 : : * BTStackData -- As we descend a tree, we push the location of pivot
734 : : * tuples whose downlink we are about to follow onto a private stack. If
735 : : * we split a leaf, we use this stack to walk back up the tree and insert
736 : : * data into its parent page at the correct location. We also have to
737 : : * recursively insert into the grandparent page if and when the parent page
738 : : * splits. Our private stack can become stale due to concurrent page
739 : : * splits and page deletions, but it should never give us an irredeemably
740 : : * bad picture.
741 : : */
742 : : typedef struct BTStackData
743 : : {
744 : : BlockNumber bts_blkno;
745 : : OffsetNumber bts_offset;
746 : : struct BTStackData *bts_parent;
747 : : } BTStackData;
748 : :
749 : : typedef BTStackData *BTStack;
750 : :
751 : : /*
752 : : * BTScanInsertData is the btree-private state needed to find an initial
753 : : * position for an indexscan, or to insert new tuples -- an "insertion
754 : : * scankey" (not to be confused with a search scankey). It's used to descend
755 : : * a B-Tree using _bt_search.
756 : : *
757 : : * heapkeyspace indicates if we expect all keys in the index to be physically
758 : : * unique because heap TID is used as a tiebreaker attribute, and if index may
759 : : * have truncated key attributes in pivot tuples. This is actually a property
760 : : * of the index relation itself (not an indexscan). heapkeyspace indexes are
761 : : * indexes whose version is >= version 4. It's convenient to keep this close
762 : : * by, rather than accessing the metapage repeatedly.
763 : : *
764 : : * allequalimage is set to indicate that deduplication is safe for the index.
765 : : * This is also a property of the index relation rather than an indexscan.
766 : : *
767 : : * anynullkeys indicates if any of the keys had NULL value when scankey was
768 : : * built from index tuple (note that already-truncated tuple key attributes
769 : : * set NULL as a placeholder key value, which also affects value of
770 : : * anynullkeys). This is a convenience for unique index non-pivot tuple
771 : : * insertion, which usually temporarily unsets scantid, but shouldn't iff
772 : : * anynullkeys is true. Value generally matches non-pivot tuple's HasNulls
773 : : * bit, but may not when inserting into an INCLUDE index (tuple header value
774 : : * is affected by the NULL-ness of both key and non-key attributes).
775 : : *
776 : : * See comments in _bt_first for an explanation of the nextkey and backward
777 : : * fields.
778 : : *
779 : : * scantid is the heap TID that is used as a final tiebreaker attribute. It
780 : : * is set to NULL when index scan doesn't need to find a position for a
781 : : * specific physical tuple. Must be set when inserting new tuples into
782 : : * heapkeyspace indexes, since every tuple in the tree unambiguously belongs
783 : : * in one exact position (it's never set with !heapkeyspace indexes, though).
784 : : * Despite the representational difference, nbtree search code considers
785 : : * scantid to be just another insertion scankey attribute.
786 : : *
787 : : * scankeys is an array of scan key entries for attributes that are compared
788 : : * before scantid (user-visible attributes). keysz is the size of the array.
789 : : * During insertion, there must be a scan key for every attribute, but when
790 : : * starting a regular index scan some can be omitted. The array is used as a
791 : : * flexible array member, though it's sized in a way that makes it possible to
792 : : * use stack allocations. See nbtree/README for full details.
793 : : */
794 : : typedef struct BTScanInsertData
795 : : {
796 : : bool heapkeyspace;
797 : : bool allequalimage;
798 : : bool anynullkeys;
799 : : bool nextkey;
800 : : bool backward; /* backward index scan? */
801 : : ItemPointer scantid; /* tiebreaker for scankeys */
802 : : int keysz; /* Size of scankeys array */
803 : : ScanKeyData scankeys[INDEX_MAX_KEYS]; /* Must appear last */
804 : : } BTScanInsertData;
805 : :
806 : : typedef BTScanInsertData *BTScanInsert;
807 : :
808 : : /*
809 : : * BTInsertStateData is a working area used during insertion.
810 : : *
811 : : * This is filled in after descending the tree to the first leaf page the new
812 : : * tuple might belong on. Tracks the current position while performing
813 : : * uniqueness check, before we have determined which exact page to insert
814 : : * to.
815 : : *
816 : : * (This should be private to nbtinsert.c, but it's also used by
817 : : * _bt_binsrch_insert)
818 : : */
819 : : typedef struct BTInsertStateData
820 : : {
821 : : IndexTuple itup; /* Item we're inserting */
822 : : Size itemsz; /* Size of itup -- should be MAXALIGN()'d */
823 : : BTScanInsert itup_key; /* Insertion scankey */
824 : :
825 : : /* Buffer containing leaf page we're likely to insert itup on */
826 : : Buffer buf;
827 : :
828 : : /*
829 : : * Cache of bounds within the current buffer. Only used for insertions
830 : : * where _bt_check_unique is called. See _bt_binsrch_insert and
831 : : * _bt_findinsertloc for details.
832 : : */
833 : : bool bounds_valid;
834 : : OffsetNumber low;
835 : : OffsetNumber stricthigh;
836 : :
837 : : /*
838 : : * if _bt_binsrch_insert found the location inside existing posting list,
839 : : * save the position inside the list. -1 sentinel value indicates overlap
840 : : * with an existing posting list tuple that has its LP_DEAD bit set.
841 : : */
842 : : int postingoff;
843 : : } BTInsertStateData;
844 : :
845 : : typedef BTInsertStateData *BTInsertState;
846 : :
847 : : /*
848 : : * State used to representing an individual pending tuple during
849 : : * deduplication.
850 : : */
851 : : typedef struct BTDedupInterval
852 : : {
853 : : OffsetNumber baseoff;
854 : : uint16 nitems;
855 : : } BTDedupInterval;
856 : :
857 : : /*
858 : : * BTDedupStateData is a working area used during deduplication.
859 : : *
860 : : * The status info fields track the state of a whole-page deduplication pass.
861 : : * State about the current pending posting list is also tracked.
862 : : *
863 : : * A pending posting list is comprised of a contiguous group of equal items
864 : : * from the page, starting from page offset number 'baseoff'. This is the
865 : : * offset number of the "base" tuple for new posting list. 'nitems' is the
866 : : * current total number of existing items from the page that will be merged to
867 : : * make a new posting list tuple, including the base tuple item. (Existing
868 : : * items may themselves be posting list tuples, or regular non-pivot tuples.)
869 : : *
870 : : * The total size of the existing tuples to be freed when pending posting list
871 : : * is processed gets tracked by 'phystupsize'. This information allows
872 : : * deduplication to calculate the space saving for each new posting list
873 : : * tuple, and for the entire pass over the page as a whole.
874 : : */
875 : : typedef struct BTDedupStateData
876 : : {
877 : : /* Deduplication status info for entire pass over page */
878 : : bool deduplicate; /* Still deduplicating page? */
879 : : int nmaxitems; /* Number of max-sized tuples so far */
880 : : Size maxpostingsize; /* Limit on size of final tuple */
881 : :
882 : : /* Metadata about base tuple of current pending posting list */
883 : : IndexTuple base; /* Use to form new posting list */
884 : : OffsetNumber baseoff; /* page offset of base */
885 : : Size basetupsize; /* base size without original posting list */
886 : :
887 : : /* Other metadata about pending posting list */
888 : : ItemPointer htids; /* Heap TIDs in pending posting list */
889 : : int nhtids; /* Number of heap TIDs in htids array */
890 : : int nitems; /* Number of existing tuples/line pointers */
891 : : Size phystupsize; /* Includes line pointer overhead */
892 : :
893 : : /*
894 : : * Array of tuples to go on new version of the page. Contains one entry
895 : : * for each group of consecutive items. Note that existing tuples that
896 : : * will not become posting list tuples do not appear in the array (they
897 : : * are implicitly unchanged by deduplication pass).
898 : : */
899 : : int nintervals; /* current number of intervals in array */
900 : : BTDedupInterval intervals[MaxIndexTuplesPerPage];
901 : : } BTDedupStateData;
902 : :
903 : : typedef BTDedupStateData *BTDedupState;
904 : :
905 : : /*
906 : : * BTVacuumPostingData is state that represents how to VACUUM (or delete) a
907 : : * posting list tuple when some (though not all) of its TIDs are to be
908 : : * deleted.
909 : : *
910 : : * Convention is that itup field is the original posting list tuple on input,
911 : : * and palloc()'d final tuple used to overwrite existing tuple on output.
912 : : */
913 : : typedef struct BTVacuumPostingData
914 : : {
915 : : /* Tuple that will be/was updated */
916 : : IndexTuple itup;
917 : : OffsetNumber updatedoffset;
918 : :
919 : : /* State needed to describe final itup in WAL */
920 : : uint16 ndeletedtids;
921 : : uint16 deletetids[FLEXIBLE_ARRAY_MEMBER];
922 : : } BTVacuumPostingData;
923 : :
924 : : typedef BTVacuumPostingData *BTVacuumPosting;
925 : :
926 : : /*
927 : : * BTScanOpaqueData is the btree-private state needed for an indexscan.
928 : : * This consists of preprocessed scan keys (see _bt_preprocess_keys() for
929 : : * details of the preprocessing), information about the current location
930 : : * of the scan, and information about the marked location, if any. (We use
931 : : * BTScanPosData to represent the data needed for each of current and marked
932 : : * locations.) In addition we can remember some known-killed index entries
933 : : * that must be marked before we can move off the current page.
934 : : *
935 : : * Index scans work a page at a time: we pin and read-lock the page, identify
936 : : * all the matching items on the page and save them in BTScanPosData, then
937 : : * release the read-lock while returning the items to the caller for
938 : : * processing. This approach minimizes lock/unlock traffic. We must always
939 : : * drop the lock to make it okay for caller to process the returned items.
940 : : * Whether or not we can also release the pin during this window will vary.
941 : : * We drop the pin (when so->dropPin) to avoid blocking progress by VACUUM
942 : : * (see nbtree/README section about making concurrent TID recycling safe).
943 : : * We'll always release both the lock and the pin on the current page before
944 : : * moving on to its sibling page.
945 : : *
946 : : * If we are doing an index-only scan, we save the entire IndexTuple for each
947 : : * matched item, otherwise only its heap TID and offset. The IndexTuples go
948 : : * into a separate workspace array; each BTScanPosItem stores its tuple's
949 : : * offset within that array. Posting list tuples store a "base" tuple once,
950 : : * allowing the same key to be returned for each TID in the posting list
951 : : * tuple.
952 : : */
953 : :
954 : : typedef struct BTScanPosItem /* what we remember about each match */
955 : : {
956 : : ItemPointerData heapTid; /* TID of referenced heap item */
957 : : OffsetNumber indexOffset; /* index item's location within page */
958 : : LocationIndex tupleOffset; /* IndexTuple's offset in workspace, if any */
959 : : } BTScanPosItem;
960 : :
961 : : typedef struct BTScanPosData
962 : : {
963 : : Buffer buf; /* currPage buf (invalid means unpinned) */
964 : :
965 : : /* page details as of the saved position's call to _bt_readpage */
966 : : BlockNumber currPage; /* page referenced by items array */
967 : : BlockNumber prevPage; /* currPage's left link */
968 : : BlockNumber nextPage; /* currPage's right link */
969 : : XLogRecPtr lsn; /* currPage's LSN (when so->dropPin) */
970 : :
971 : : /* scan direction for the saved position's call to _bt_readpage */
972 : : ScanDirection dir;
973 : :
974 : : /*
975 : : * If we are doing an index-only scan, nextTupleOffset is the first free
976 : : * location in the associated tuple storage workspace.
977 : : */
978 : : int nextTupleOffset;
979 : :
980 : : /*
981 : : * moreLeft and moreRight track whether we think there may be matching
982 : : * index entries to the left and right of the current page, respectively.
983 : : */
984 : : bool moreLeft;
985 : : bool moreRight;
986 : :
987 : : /*
988 : : * The items array is always ordered in index order (ie, increasing
989 : : * indexoffset). When scanning backwards it is convenient to fill the
990 : : * array back-to-front, so we start at the last slot and fill downwards.
991 : : * Hence we need both a first-valid-entry and a last-valid-entry counter.
992 : : * itemIndex is a cursor showing which entry was last returned to caller.
993 : : */
994 : : int firstItem; /* first valid index in items[] */
995 : : int lastItem; /* last valid index in items[] */
996 : : int itemIndex; /* current index in items[] */
997 : :
998 : : BTScanPosItem items[MaxTIDsPerBTreePage]; /* MUST BE LAST */
999 : : } BTScanPosData;
1000 : :
1001 : : typedef BTScanPosData *BTScanPos;
1002 : :
1003 : : #define BTScanPosIsPinned(scanpos) \
1004 : : ( \
1005 : : AssertMacro(BlockNumberIsValid((scanpos).currPage) || \
1006 : : !BufferIsValid((scanpos).buf)), \
1007 : : BufferIsValid((scanpos).buf) \
1008 : : )
1009 : : #define BTScanPosUnpin(scanpos) \
1010 : : do { \
1011 : : ReleaseBuffer((scanpos).buf); \
1012 : : (scanpos).buf = InvalidBuffer; \
1013 : : } while (0)
1014 : : #define BTScanPosUnpinIfPinned(scanpos) \
1015 : : do { \
1016 : : if (BTScanPosIsPinned(scanpos)) \
1017 : : BTScanPosUnpin(scanpos); \
1018 : : } while (0)
1019 : :
1020 : : #define BTScanPosIsValid(scanpos) \
1021 : : ( \
1022 : : AssertMacro(BlockNumberIsValid((scanpos).currPage) || \
1023 : : !BufferIsValid((scanpos).buf)), \
1024 : : BlockNumberIsValid((scanpos).currPage) \
1025 : : )
1026 : : #define BTScanPosInvalidate(scanpos) \
1027 : : do { \
1028 : : (scanpos).buf = InvalidBuffer; \
1029 : : (scanpos).currPage = InvalidBlockNumber; \
1030 : : } while (0)
1031 : :
1032 : : /* We need one of these for each equality-type SK_SEARCHARRAY scan key */
1033 : : typedef struct BTArrayKeyInfo
1034 : : {
1035 : : /* fields set for both kinds of array (SAOP arrays and skip arrays) */
1036 : : int scan_key; /* index of associated key in keyData */
1037 : : int num_elems; /* number of elems (-1 means skip array) */
1038 : :
1039 : : /* fields set for ScalarArrayOpExpr arrays only */
1040 : : Datum *elem_values; /* array of num_elems Datums */
1041 : : int cur_elem; /* index of current element in elem_values */
1042 : :
1043 : : /* fields set for skip arrays only */
1044 : : int16 attlen; /* attr's length, in bytes */
1045 : : bool attbyval; /* attr's FormData_pg_attribute.attbyval */
1046 : : bool null_elem; /* NULL is lowest/highest element? */
1047 : : SkipSupport sksup; /* skip support (NULL if opclass lacks it) */
1048 : : ScanKey low_compare; /* array's > or >= lower bound */
1049 : : ScanKey high_compare; /* array's < or <= upper bound */
1050 : : } BTArrayKeyInfo;
1051 : :
1052 : : typedef struct BTScanOpaqueData
1053 : : {
1054 : : /* these fields are set by _bt_preprocess_keys(): */
1055 : : bool qual_ok; /* false if qual can never be satisfied */
1056 : : int numberOfKeys; /* number of preprocessed scan keys */
1057 : : ScanKey keyData; /* array of preprocessed scan keys */
1058 : :
1059 : : /* workspace for SK_SEARCHARRAY support */
1060 : : int numArrayKeys; /* number of equality-type array keys */
1061 : : bool skipScan; /* At least one skip array in arrayKeys[]? */
1062 : : bool needPrimScan; /* New prim scan to continue in current dir? */
1063 : : bool scanBehind; /* Check scan not still behind on next page? */
1064 : : bool oppositeDirCheck; /* scanBehind opposite-scan-dir check? */
1065 : : BTArrayKeyInfo *arrayKeys; /* info about each equality-type array key */
1066 : : FmgrInfo *orderProcs; /* ORDER procs for required equality keys */
1067 : : MemoryContext arrayContext; /* scan-lifespan context for array data */
1068 : :
1069 : : /* info about killed items if any (killedItems is NULL if never used) */
1070 : : int *killedItems; /* currPos.items indexes of killed items */
1071 : : int numKilled; /* number of currently stored items */
1072 : : bool dropPin; /* drop leaf pin before btgettuple returns? */
1073 : :
1074 : : /*
1075 : : * If we are doing an index-only scan, these are the tuple storage
1076 : : * workspaces for the currPos and markPos respectively. Each is of size
1077 : : * BLCKSZ, so it can hold as much as a full page's worth of tuples.
1078 : : */
1079 : : char *currTuples; /* tuple storage for currPos */
1080 : : char *markTuples; /* tuple storage for markPos */
1081 : :
1082 : : /*
1083 : : * If the marked position is on the same page as current position, we
1084 : : * don't use markPos, but just keep the marked itemIndex in markItemIndex
1085 : : * (all the rest of currPos is valid for the mark position). Hence, to
1086 : : * determine if there is a mark, first look at markItemIndex, then at
1087 : : * markPos.
1088 : : */
1089 : : int markItemIndex; /* itemIndex, or -1 if not valid */
1090 : :
1091 : : /* keep these last in struct for efficiency */
1092 : : BTScanPosData currPos; /* current position data */
1093 : : BTScanPosData markPos; /* marked position, if any */
1094 : : } BTScanOpaqueData;
1095 : :
1096 : : typedef BTScanOpaqueData *BTScanOpaque;
1097 : :
1098 : : /*
1099 : : * _bt_readpage state used across _bt_checkkeys calls for a page
1100 : : */
1101 : : typedef struct BTReadPageState
1102 : : {
1103 : : /* Input parameters, set by _bt_readpage for _bt_checkkeys */
1104 : : OffsetNumber minoff; /* Lowest non-pivot tuple's offset */
1105 : : OffsetNumber maxoff; /* Highest non-pivot tuple's offset */
1106 : : IndexTuple finaltup; /* Needed by scans with array keys */
1107 : : Page page; /* Page being read */
1108 : : bool firstpage; /* page is first for primitive scan? */
1109 : : bool forcenonrequired; /* treat all keys as nonrequired? */
1110 : : int startikey; /* start comparisons from this scan key */
1111 : :
1112 : : /* Per-tuple input parameters, set by _bt_readpage for _bt_checkkeys */
1113 : : OffsetNumber offnum; /* current tuple's page offset number */
1114 : :
1115 : : /* Output parameters, set by _bt_checkkeys for _bt_readpage */
1116 : : OffsetNumber skip; /* Array keys "look ahead" skip offnum */
1117 : : bool continuescan; /* Terminate ongoing (primitive) index scan? */
1118 : :
1119 : : /*
1120 : : * Private _bt_checkkeys state used to manage "look ahead" optimization
1121 : : * and primscan scheduling (only used during scans with array keys)
1122 : : */
1123 : : int16 rechecks;
1124 : : int16 targetdistance;
1125 : : int16 nskipadvances;
1126 : :
1127 : : } BTReadPageState;
1128 : :
1129 : : /*
1130 : : * We use some private sk_flags bits in preprocessed scan keys. We're allowed
1131 : : * to use bits 16-31 (see skey.h). The uppermost bits are copied from the
1132 : : * index's indoption[] array entry for the index attribute.
1133 : : */
1134 : : #define SK_BT_REQFWD 0x00010000 /* required to continue forward scan */
1135 : : #define SK_BT_REQBKWD 0x00020000 /* required to continue backward scan */
1136 : : #define SK_BT_SKIP 0x00040000 /* skip array on column without input = */
1137 : :
1138 : : /* SK_BT_SKIP-only flags (set and unset by array advancement) */
1139 : : #define SK_BT_MINVAL 0x00080000 /* invalid sk_argument, use low_compare */
1140 : : #define SK_BT_MAXVAL 0x00100000 /* invalid sk_argument, use high_compare */
1141 : : #define SK_BT_NEXT 0x00200000 /* positions the scan > sk_argument */
1142 : : #define SK_BT_PRIOR 0x00400000 /* positions the scan < sk_argument */
1143 : :
1144 : : /* Remaps pg_index flag bits to uppermost SK_BT_* byte */
1145 : : #define SK_BT_INDOPTION_SHIFT 24 /* must clear the above bits */
1146 : : #define SK_BT_DESC (INDOPTION_DESC << SK_BT_INDOPTION_SHIFT)
1147 : : #define SK_BT_NULLS_FIRST (INDOPTION_NULLS_FIRST << SK_BT_INDOPTION_SHIFT)
1148 : :
1149 : : typedef struct BTOptions
1150 : : {
1151 : : int32 varlena_header_; /* varlena header (do not touch directly!) */
1152 : : int fillfactor; /* page fill factor in percent (0..100) */
1153 : : float8 vacuum_cleanup_index_scale_factor; /* deprecated */
1154 : : bool deduplicate_items; /* Try to deduplicate items? */
1155 : : } BTOptions;
1156 : :
1157 : : #define BTGetFillFactor(relation) \
1158 : : (AssertMacro(relation->rd_rel->relkind == RELKIND_INDEX && \
1159 : : relation->rd_rel->relam == BTREE_AM_OID), \
1160 : : (relation)->rd_options ? \
1161 : : ((BTOptions *) (relation)->rd_options)->fillfactor : \
1162 : : BTREE_DEFAULT_FILLFACTOR)
1163 : : #define BTGetTargetPageFreeSpace(relation) \
1164 : : (BLCKSZ * (100 - BTGetFillFactor(relation)) / 100)
1165 : : #define BTGetDeduplicateItems(relation) \
1166 : : (AssertMacro(relation->rd_rel->relkind == RELKIND_INDEX && \
1167 : : relation->rd_rel->relam == BTREE_AM_OID), \
1168 : : ((relation)->rd_options ? \
1169 : : ((BTOptions *) (relation)->rd_options)->deduplicate_items : true))
1170 : :
1171 : : /*
1172 : : * Constant definition for progress reporting. Phase numbers must match
1173 : : * btbuildphasename.
1174 : : */
1175 : : /* PROGRESS_CREATEIDX_SUBPHASE_INITIALIZE is 1 (see progress.h) */
1176 : : #define PROGRESS_BTREE_PHASE_INDEXBUILD_TABLESCAN 2
1177 : : #define PROGRESS_BTREE_PHASE_PERFORMSORT_1 3
1178 : : #define PROGRESS_BTREE_PHASE_PERFORMSORT_2 4
1179 : : #define PROGRESS_BTREE_PHASE_LEAF_LOAD 5
1180 : :
1181 : : /*
1182 : : * external entry points for btree, in nbtree.c
1183 : : */
1184 : : extern void btbuildempty(Relation index);
1185 : : extern bool btinsert(Relation rel, Datum *values, bool *isnull,
1186 : : ItemPointer ht_ctid, Relation heapRel,
1187 : : IndexUniqueCheck checkUnique,
1188 : : bool indexUnchanged,
1189 : : struct IndexInfo *indexInfo);
1190 : : extern IndexScanDesc btbeginscan(Relation rel, int nkeys, int norderbys);
1191 : : extern Size btestimateparallelscan(Relation rel, int nkeys, int norderbys);
1192 : : extern void btinitparallelscan(void *target);
1193 : : extern bool btgettuple(IndexScanDesc scan, ScanDirection dir);
1194 : : extern int64 btgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
1195 : : extern void btrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
1196 : : ScanKey orderbys, int norderbys);
1197 : : extern void btparallelrescan(IndexScanDesc scan);
1198 : : extern void btendscan(IndexScanDesc scan);
1199 : : extern void btmarkpos(IndexScanDesc scan);
1200 : : extern void btrestrpos(IndexScanDesc scan);
1201 : : extern IndexBulkDeleteResult *btbulkdelete(IndexVacuumInfo *info,
1202 : : IndexBulkDeleteResult *stats,
1203 : : IndexBulkDeleteCallback callback,
1204 : : void *callback_state);
1205 : : extern IndexBulkDeleteResult *btvacuumcleanup(IndexVacuumInfo *info,
1206 : : IndexBulkDeleteResult *stats);
1207 : : extern bool btcanreturn(Relation index, int attno);
1208 : : extern int btgettreeheight(Relation rel);
1209 : :
1210 : : extern CompareType bttranslatestrategy(StrategyNumber strategy, Oid opfamily);
1211 : : extern StrategyNumber bttranslatecmptype(CompareType cmptype, Oid opfamily);
1212 : :
1213 : : /*
1214 : : * prototypes for internal functions in nbtree.c
1215 : : */
1216 : : extern bool _bt_parallel_seize(IndexScanDesc scan, BlockNumber *next_scan_page,
1217 : : BlockNumber *last_curr_page, bool first);
1218 : : extern void _bt_parallel_release(IndexScanDesc scan,
1219 : : BlockNumber next_scan_page,
1220 : : BlockNumber curr_page);
1221 : : extern void _bt_parallel_done(IndexScanDesc scan);
1222 : : extern void _bt_parallel_primscan_schedule(IndexScanDesc scan,
1223 : : BlockNumber curr_page);
1224 : :
1225 : : /*
1226 : : * prototypes for functions in nbtdedup.c
1227 : : */
1228 : : extern void _bt_dedup_pass(Relation rel, Buffer buf, IndexTuple newitem,
1229 : : Size newitemsz, bool bottomupdedup);
1230 : : extern bool _bt_bottomupdel_pass(Relation rel, Buffer buf, Relation heapRel,
1231 : : Size newitemsz);
1232 : : extern void _bt_dedup_start_pending(BTDedupState state, IndexTuple base,
1233 : : OffsetNumber baseoff);
1234 : : extern bool _bt_dedup_save_htid(BTDedupState state, IndexTuple itup);
1235 : : extern Size _bt_dedup_finish_pending(Page newpage, BTDedupState state);
1236 : : extern IndexTuple _bt_form_posting(IndexTuple base, ItemPointer htids,
1237 : : int nhtids);
1238 : : extern void _bt_update_posting(BTVacuumPosting vacposting);
1239 : : extern IndexTuple _bt_swap_posting(IndexTuple newitem, IndexTuple oposting,
1240 : : int postingoff);
1241 : :
1242 : : /*
1243 : : * prototypes for functions in nbtinsert.c
1244 : : */
1245 : : extern bool _bt_doinsert(Relation rel, IndexTuple itup,
1246 : : IndexUniqueCheck checkUnique, bool indexUnchanged,
1247 : : Relation heapRel);
1248 : : extern void _bt_finish_split(Relation rel, Relation heaprel, Buffer lbuf,
1249 : : BTStack stack);
1250 : : extern Buffer _bt_getstackbuf(Relation rel, Relation heaprel, BTStack stack,
1251 : : BlockNumber child);
1252 : :
1253 : : /*
1254 : : * prototypes for functions in nbtsplitloc.c
1255 : : */
1256 : : extern OffsetNumber _bt_findsplitloc(Relation rel, Page origpage,
1257 : : OffsetNumber newitemoff, Size newitemsz, IndexTuple newitem,
1258 : : bool *newitemonleft);
1259 : :
1260 : : /*
1261 : : * prototypes for functions in nbtpage.c
1262 : : */
1263 : : extern void _bt_initmetapage(Page page, BlockNumber rootbknum, uint32 level,
1264 : : bool allequalimage);
1265 : : extern bool _bt_vacuum_needs_cleanup(Relation rel);
1266 : : extern void _bt_set_cleanup_info(Relation rel, BlockNumber num_delpages);
1267 : : extern void _bt_upgrademetapage(Page page);
1268 : : extern Buffer _bt_getroot(Relation rel, Relation heaprel, int access);
1269 : : extern Buffer _bt_gettrueroot(Relation rel);
1270 : : extern int _bt_getrootheight(Relation rel);
1271 : : extern void _bt_metaversion(Relation rel, bool *heapkeyspace,
1272 : : bool *allequalimage);
1273 : : extern void _bt_checkpage(Relation rel, Buffer buf);
1274 : : extern Buffer _bt_getbuf(Relation rel, BlockNumber blkno, int access);
1275 : : extern Buffer _bt_allocbuf(Relation rel, Relation heaprel);
1276 : : extern Buffer _bt_relandgetbuf(Relation rel, Buffer obuf,
1277 : : BlockNumber blkno, int access);
1278 : : extern void _bt_relbuf(Relation rel, Buffer buf);
1279 : : extern void _bt_lockbuf(Relation rel, Buffer buf, int access);
1280 : : extern void _bt_unlockbuf(Relation rel, Buffer buf);
1281 : : extern bool _bt_conditionallockbuf(Relation rel, Buffer buf);
1282 : : extern void _bt_upgradelockbufcleanup(Relation rel, Buffer buf);
1283 : : extern void _bt_pageinit(Page page, Size size);
1284 : : extern void _bt_delitems_vacuum(Relation rel, Buffer buf,
1285 : : OffsetNumber *deletable, int ndeletable,
1286 : : BTVacuumPosting *updatable, int nupdatable);
1287 : : struct TM_IndexDeleteOp; /* avoid including tableam.h here */
1288 : : extern void _bt_delitems_delete_check(Relation rel, Buffer buf,
1289 : : Relation heapRel,
1290 : : struct TM_IndexDeleteOp *delstate);
1291 : : extern void _bt_pagedel(Relation rel, Buffer leafbuf, BTVacState *vstate);
1292 : : extern void _bt_pendingfsm_init(Relation rel, BTVacState *vstate,
1293 : : bool cleanuponly);
1294 : : extern void _bt_pendingfsm_finalize(Relation rel, BTVacState *vstate);
1295 : :
1296 : : /*
1297 : : * prototypes for functions in nbtpreprocesskeys.c
1298 : : */
1299 : : extern void _bt_preprocess_keys(IndexScanDesc scan);
1300 : :
1301 : : /*
1302 : : * prototypes for functions in nbtsearch.c
1303 : : */
1304 : : extern BTStack _bt_search(Relation rel, Relation heaprel, BTScanInsert key,
1305 : : Buffer *bufP, int access);
1306 : : extern OffsetNumber _bt_binsrch_insert(Relation rel, BTInsertState insertstate);
1307 : : extern int32 _bt_compare(Relation rel, BTScanInsert key, Page page, OffsetNumber offnum);
1308 : : extern bool _bt_first(IndexScanDesc scan, ScanDirection dir);
1309 : : extern bool _bt_next(IndexScanDesc scan, ScanDirection dir);
1310 : : extern Buffer _bt_get_endpoint(Relation rel, uint32 level, bool rightmost);
1311 : :
1312 : : /*
1313 : : * prototypes for functions in nbtutils.c
1314 : : */
1315 : : extern BTScanInsert _bt_mkscankey(Relation rel, IndexTuple itup);
1316 : : extern void _bt_freestack(BTStack stack);
1317 : : extern bool _bt_start_prim_scan(IndexScanDesc scan, ScanDirection dir);
1318 : : extern int _bt_binsrch_array_skey(FmgrInfo *orderproc,
1319 : : bool cur_elem_trig, ScanDirection dir,
1320 : : Datum tupdatum, bool tupnull,
1321 : : BTArrayKeyInfo *array, ScanKey cur,
1322 : : int32 *set_elem_result);
1323 : : extern void _bt_start_array_keys(IndexScanDesc scan, ScanDirection dir);
1324 : : extern bool _bt_checkkeys(IndexScanDesc scan, BTReadPageState *pstate, bool arrayKeys,
1325 : : IndexTuple tuple, int tupnatts);
1326 : : extern bool _bt_scanbehind_checkkeys(IndexScanDesc scan, ScanDirection dir,
1327 : : IndexTuple finaltup);
1328 : : extern void _bt_set_startikey(IndexScanDesc scan, BTReadPageState *pstate);
1329 : : extern void _bt_killitems(IndexScanDesc scan);
1330 : : extern BTCycleId _bt_vacuum_cycleid(Relation rel);
1331 : : extern BTCycleId _bt_start_vacuum(Relation rel);
1332 : : extern void _bt_end_vacuum(Relation rel);
1333 : : extern void _bt_end_vacuum_callback(int code, Datum arg);
1334 : : extern Size BTreeShmemSize(void);
1335 : : extern void BTreeShmemInit(void);
1336 : : extern bytea *btoptions(Datum reloptions, bool validate);
1337 : : extern bool btproperty(Oid index_oid, int attno,
1338 : : IndexAMProperty prop, const char *propname,
1339 : : bool *res, bool *isnull);
1340 : : extern char *btbuildphasename(int64 phasenum);
1341 : : extern IndexTuple _bt_truncate(Relation rel, IndexTuple lastleft,
1342 : : IndexTuple firstright, BTScanInsert itup_key);
1343 : : extern int _bt_keep_natts_fast(Relation rel, IndexTuple lastleft,
1344 : : IndexTuple firstright);
1345 : : extern bool _bt_check_natts(Relation rel, bool heapkeyspace, Page page,
1346 : : OffsetNumber offnum);
1347 : : extern void _bt_check_third_page(Relation rel, Relation heap,
1348 : : bool needheaptidspace, Page page, IndexTuple newtup);
1349 : : extern bool _bt_allequalimage(Relation rel, bool debugmessage);
1350 : :
1351 : : /*
1352 : : * prototypes for functions in nbtvalidate.c
1353 : : */
1354 : : extern bool btvalidate(Oid opclassoid);
1355 : : extern void btadjustmembers(Oid opfamilyoid,
1356 : : Oid opclassoid,
1357 : : List *operators,
1358 : : List *functions);
1359 : :
1360 : : /*
1361 : : * prototypes for functions in nbtsort.c
1362 : : */
1363 : : extern IndexBuildResult *btbuild(Relation heap, Relation index,
1364 : : struct IndexInfo *indexInfo);
1365 : : extern void _bt_parallel_build_main(dsm_segment *seg, shm_toc *toc);
1366 : :
1367 : : #endif /* NBTREE_H */
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