Line data Source code
1 : /*
2 : * SPDX-License-Identifier: MPL-2.0
3 : *
4 : * This Source Code Form is subject to the terms of the Mozilla Public
5 : * License, v. 2.0. If a copy of the MPL was not distributed with this
6 : * file, You can obtain one at http://mozilla.org/MPL/2.0/.
7 : *
8 : * Copyright 2024 MonetDB Foundation;
9 : * Copyright August 2008 - 2023 MonetDB B.V.;
10 : * Copyright 1997 - July 2008 CWI.
11 : */
12 :
13 : /* Author: Panagiotis Koutsourakis
14 : *
15 : * A string imprint is an index that can be used as a prefilter in LIKE
16 : * queries. It has 2 components:
17 : *
18 : * - a header of 63 string element pairs.
19 : *
20 : * - a 64 bit mask for each string in the BAT that encodes the presence
21 : * or absence of each element of the header in the specific item or if
22 : * the corresponding entry in the BAT is nil.
23 : *
24 : * A string imprint is stored in a new Heap in the BAT, aligned in 8
25 : * byte (64 bit) words.
26 : *
27 : * The first 64 bit word, the header descriptor, describes how the
28 : * header of the strimp is encoded. The least significant byte (v in the
29 : * schematic below) is the version number. The second (np) is the number
30 : * of pairs in the header. In the current implementation this is always
31 : * 63. The next 2 bytes (hs) is the total size of the header in
32 : * bytes. Finally the fifth byte is the persistence byte. The last 3
33 : * bytes needed to align to the 8 byte boundary should be zero, and are
34 : * reserved for future use.
35 : *
36 : * The following np + 1 bytes are the sizes of the pairs. These can have
37 : * values from 2 to 8 and are the number of bytes that the corresponding
38 : * pair takes up. Following that there are the bytes encoding the actual
39 : * pairs.
40 : *
41 : * | 1byte | 1byte | 1byte | 1byte | 1byte | 1byte | 1byte | 1byte |
42 : * |---------------------------------------------------------------|
43 : * | v | np | hs | p | reserved | 8bytes ---
44 : * |---------------------------------------------------------------| ___ |
45 : * | psz_0 | psz_1 | ... | | |
46 : * | | | |
47 : * | |np bytes |
48 : * | | | |
49 : * | ... | psz_n | | hs bytes
50 : * |---------------------------------------------------------------| ___ |
51 : * | pair_0 | pair_1 | |
52 : * | ... | |
53 : * | pair_k-1 | pair_k | |
54 : * | pair_n | |
55 : * |---------------------------------------------------------------| ---
56 : *
57 : *
58 : * The bitmasks for each string in the BAT follow after this, aligned to
59 : * the string BAT.
60 : *
61 : * Strimp creation goes as follows:
62 : *
63 : * - Construct a histogram of all the element pairs for all the strings
64 : * in the BAT.
65 : *
66 : * - Take the np most frequent pairs as the Strimp Header.
67 : *
68 : * - For each string s in the BAT, construct an (np + 1)-bit mask, m_s
69 : * that encodes the presence or absence of each member of the header
70 : * in the string or if s is nil.
71 : *
72 : * Filtering with a query string q goes as follows:
73 : *
74 : * - Use the strimp header to construct an (np + 1)-bit mask for q
75 : * encoding the presence or absence of each member of the header in q.
76 : *
77 : * - For each bitmask in the strimp, first check if it encodes a nil
78 : * value and keep it if it needs to be kept (this happens for NOT LIKE
79 : * queries). Otherwise compute the bitwise AND of m_s and q. If the
80 : * result is equal to q, that means that string s contains the same
81 : * strimp header elements as q, so it is kept for more detailed
82 : * examination.
83 : */
84 :
85 : #include "monetdb_config.h"
86 : #include "gdk.h"
87 : #include "gdk_private.h"
88 :
89 : #include <stdint.h>
90 : #include <inttypes.h>
91 :
92 : #define STRIMP_VERSION (uint64_t)2
93 : #define STRIMP_HISTSIZE (256*256)
94 : #define STRIMP_HEADER_SIZE 64
95 : #define STRIMP_PAIRS (STRIMP_HEADER_SIZE - 1)
96 : #define STRIMP_CREATION_THRESHOLD \
97 : ((BUN) ((ATOMIC_GET(&GDKdebug) & FORCEMITOMASK)? 100 : 5000))
98 :
99 : typedef struct {
100 : #ifdef UTF8STRIMPS
101 : uint8_t *pbytes;
102 : #else
103 : uint8_t pbytes[2];
104 : #endif //UTF8STRIMPSX
105 : uint8_t psize;
106 : size_t idx;
107 : uint64_t mask;
108 : } CharPair;
109 :
110 : typedef struct {
111 : size_t pos;
112 : size_t lim;
113 : const char *s;
114 : } PairIterator;
115 :
116 : typedef struct {
117 : uint64_t cnt;
118 : } PairHistogramElem;
119 :
120 :
121 : /* Macros for accessing metadada of a strimp. These are recorded in the
122 : * first 8 bytes of the heap.
123 : */
124 : #define NPAIRS(d) (size_t)(((d) >> 8) & 0xff)
125 : #define HSIZE(d) (size_t)(((d) >> 16) & 0xffff)
126 :
127 : #undef UTF8STRIMPS /* Not using utf8 for now */
128 : #ifdef UTF8STRIMPS
129 : static bool
130 : pair_equal(const CharPair *p1, const CharPair *p2)
131 : {
132 : if(p1->psize != p2->psize)
133 : return false;
134 :
135 : for(size_t i = 0; i < p1->psize; i++)
136 : if (p1->pbytes[i] != p2->pbytes[i])
137 : return false;
138 :
139 : return true;
140 : }
141 : #else
142 : /* BytePairs implementation.
143 : *
144 : * The header elements are pairs of bytes. In this case the histogram is
145 : * 256*256=65536 entries long. We use the numeric value of the 2 byte
146 : * sequence of the pair as the index to the histogram.
147 : *
148 : * Note: All the of the following functions and macros up to #endif need to be
149 : * implemented for the UTF8 case.
150 : */
151 :
152 : /* We disregard spaces, digits and punctuation characters */
153 : #define isIgnored(x) (isspace((x)) || isdigit((x)) || ispunct((x)))
154 : #define pairToIndex(b1, b2) (size_t)(((uint16_t)b2)<<8 | ((uint16_t)b1))
155 :
156 : inline static size_t
157 63 : bytes2histindex(uint8_t *bytes, uint8_t psize)
158 : {
159 63 : (void)psize;
160 63 : return pairToIndex(bytes[0], bytes[1]);
161 : }
162 :
163 : inline static bool
164 7662267 : pair_at(const PairIterator *pi, CharPair *p)
165 : {
166 7662267 : if (pi->pos >= pi->lim - 1)
167 : return false;
168 :
169 7471854 : p->pbytes[0] = (uint8_t)tolower((unsigned char) pi->s[pi->pos]);
170 7471854 : p->pbytes[1] = (uint8_t)tolower((unsigned char) pi->s[pi->pos + 1]);
171 :
172 7471854 : p->psize = 2;
173 7471854 : p->idx = pairToIndex(p->pbytes[0], p->pbytes[1]);
174 7471854 : return true;
175 : }
176 :
177 : inline static bool
178 8188470 : next_pair(PairIterator *pi)
179 : {
180 8188470 : if (pi->pos >= pi->lim - 1)
181 : return false;
182 8173110 : pi->pos++;
183 8173110 : return true;
184 : }
185 :
186 : /* Returns true if the specified char is ignored.
187 : */
188 : inline static bool
189 9157304 : ignored(const CharPair *p, uint8_t elm)
190 : {
191 9157304 : assert(elm == 0 || elm == 1);
192 9157304 : return isIgnored(p->pbytes[elm]);
193 : }
194 :
195 : inline static strimp_masks_t
196 2470628 : STRMPget_mask(const Strimps *r, uint64_t idx)
197 : {
198 2470628 : return r->masks[idx];
199 : }
200 :
201 : inline static void
202 63 : STRMPset_mask(Strimps *r, uint64_t idx, strimp_masks_t val)
203 : {
204 63 : r->masks[idx] = val;
205 : }
206 :
207 : /* Looks up a given pair in the strimp header and returns the index as a
208 : * 64 bit integer. The return value has a bit on in the position
209 : * corresponding to the index of the pair in the strimp header, or is 0
210 : * if the pair does not occur.
211 : */
212 : inline static uint64_t
213 2470628 : STRMPpairLookup(const Strimps *s, const CharPair *p)
214 : {
215 2470628 : return STRMPget_mask(s, p->idx);
216 : }
217 :
218 :
219 : #endif // UTF8STRIMPS
220 :
221 :
222 : /* Computes the bitstring of a string s with respect to the strimp r.
223 : *
224 : */
225 : static uint64_t
226 62161 : STRMPmakebitstring(const char *s, Strimps *r)
227 : {
228 62161 : uint64_t ret = 0;
229 : /* int8_t pair_idx = 0; */
230 62161 : PairIterator pi;
231 62161 : CharPair cp;
232 :
233 62161 : pi.s = s;
234 62161 : pi.pos = 0;
235 62161 : pi.lim = strlen(s);
236 :
237 62161 : if (pi.lim < 2) {
238 : return ret;
239 : }
240 :
241 2540403 : while(pair_at(&pi, &cp)) {
242 2470628 : ret |= STRMPpairLookup(r, &cp);
243 5003415 : next_pair(&pi);
244 : }
245 :
246 : return ret;
247 : }
248 :
249 : #define SWAP(_a, _i, _j, TPE) \
250 : do { \
251 : TPE _t = ((TPE *)_a)[_i]; \
252 : ((TPE *) _a)[_i] = ((TPE *) _a)[_j]; \
253 : ((TPE *) _a)[_j] = _t; \
254 : } while(0)
255 :
256 :
257 :
258 : static void
259 5 : STRMPchoosePairs(const PairHistogramElem *hist, size_t hist_size, CharPair *cp)
260 : {
261 5 : lng t0 = 0;
262 5 : size_t i;
263 5 : uint64_t max_counts[STRIMP_HEADER_SIZE] = {0};
264 5 : size_t indices[STRIMP_HEADER_SIZE] = {0};
265 5 : const size_t cmin_max = STRIMP_HEADER_SIZE - 1;
266 5 : size_t hidx;
267 :
268 5 : TRC_DEBUG_IF(ACCELERATOR) t0 = GDKusec();
269 :
270 327685 : for(i = 0; i < hist_size; i++) {
271 327680 : if (max_counts[cmin_max] < hist[i].cnt) {
272 660 : max_counts[cmin_max] = hist[i].cnt;
273 660 : indices[cmin_max] = i;
274 26237 : for(hidx = cmin_max; hidx > 0 && max_counts[hidx] > max_counts[hidx-1]; hidx--) {
275 25577 : SWAP(max_counts, hidx, hidx-1, uint64_t);
276 25577 : SWAP(indices, hidx, hidx-1, size_t);
277 : }
278 : }
279 : }
280 :
281 320 : for(i = 0; i < STRIMP_PAIRS; i++) {
282 315 : cp[i].pbytes[1] = (uint8_t)(indices[i] & 0xFF);
283 315 : cp[i].pbytes[0] = (uint8_t)((indices[i] >> 8) & 0xFF);
284 315 : cp[i].idx = indices[i];
285 315 : cp[i].psize = 2;
286 315 : cp[i].mask = ((uint64_t)0x1) << (STRIMP_PAIRS - i - 1);
287 : }
288 5 : cp[STRIMP_PAIRS] = (CharPair) {.psize = 2};
289 :
290 5 : TRC_DEBUG(ACCELERATOR, LLFMT " usec\n", GDKusec() - t0);
291 5 : }
292 :
293 : /* Given a BAT b and a candidate list s constructs the header elements
294 : * of the strimp.
295 : *
296 : * Initially creates the histogram for the all the pairs in the candidate
297 : * and then chooses the STRIMP_HEADER_SIZE most frequent of them.
298 : */
299 : static bool
300 5 : STRMPbuildHeader(BAT *b, BAT *s, CharPair *hpairs)
301 : {
302 5 : lng t0 = 0;
303 5 : BATiter bi;
304 5 : BUN i;
305 5 : size_t hidx;
306 5 : oid x;
307 5 : size_t hlen;
308 5 : PairHistogramElem *hist;
309 5 : PairIterator pi;
310 5 : CharPair cp;
311 5 : struct canditer ci;
312 5 : size_t values = 0;
313 5 : bool res;
314 :
315 5 : TRC_DEBUG_IF(ACCELERATOR) t0 = GDKusec();
316 :
317 5 : canditer_init(&ci, b, s);
318 5 : if (ci.ncand == 0) {
319 0 : GDKerror("Not enough distinct values to create strimp index\n");
320 0 : return false;
321 : }
322 :
323 5 : hlen = STRIMP_HISTSIZE;
324 5 : if ((hist = (PairHistogramElem *)GDKzalloc(hlen*sizeof(PairHistogramElem))) == NULL) {
325 : return false;
326 : }
327 :
328 : // Create Histogram
329 5 : bi = bat_iterator(b);
330 120310 : for (i = 0; i < ci.ncand; i++) {
331 120300 : x = canditer_next(&ci) - b->hseqbase;
332 120300 : const char *cs = BUNtvar(bi, x);
333 240600 : if (!strNil(cs)) {
334 120296 : pi.s = cs;
335 120296 : pi.pos = 0;
336 120296 : pi.lim = strlen(pi.s);
337 120296 : if (pi.lim < 2) {
338 2 : continue;
339 : }
340 5078676 : while (pair_at(&pi, &cp)) {
341 4958382 : if(ignored(&cp, 1)) {
342 : /* Skip this AND the next pair
343 : * if the second char of the
344 : * pair is ignored.
345 : */
346 759460 : next_pair(&pi);
347 4198922 : } else if (ignored(&cp, 0)) {
348 : /* Skip this pair if the first
349 : * char is ignored. This should
350 : * only happen at the beginning
351 : * of a string, since the pair
352 : * will have been ignored in the
353 : * previous case.
354 : */
355 : ;
356 :
357 : } else {
358 : /* hidx = histogram_index(hist, hlen, &cp); */
359 4072175 : hidx = cp.idx;
360 : #ifndef UTF8STRINGS
361 4072175 : assert(hidx < hlen);
362 : #else
363 : if (hidx >= hlen) {
364 : // TODO: Note and realloc. Should not happen for bytepairs.
365 : continue;
366 : }
367 : #endif
368 4072175 : if (!hist[hidx].cnt)
369 1194 : values++;
370 4072175 : hist[hidx].cnt++;
371 : }
372 10037058 : next_pair(&pi);
373 : }
374 : }
375 : }
376 5 : bat_iterator_end(&bi);
377 :
378 : // Check that we have enough values in the histogram.
379 5 : if(values >= STRIMP_HEADER_SIZE) {
380 : // Choose the header pairs
381 5 : STRMPchoosePairs(hist, hlen, hpairs);
382 : }
383 :
384 5 : GDKfree(hist);
385 :
386 5 : TRC_DEBUG(ACCELERATOR, LLFMT " usec\n", GDKusec() - t0);
387 5 : if (!(res = values >= STRIMP_HEADER_SIZE))
388 0 : GDKerror("Not enough distinct values to create strimp index\n");
389 : return res;
390 : }
391 :
392 : /* Read a strimp structure from disk.
393 : *
394 : * If the pointer b->tstrimps has the value 1, it means that the strimp
395 : * is on disk. This routine attempts to read it so that it can be used.
396 : *
397 : * There are a number of checks made for example we check that the
398 : * strimps version on disk matches the one the code recognizes, and that
399 : * the number of pairs encoded on disk matches the one we expect. If any
400 : * of these checks fail, we remove the file from disk since it is now
401 : * unusable, and set the pointer b->tstrimps to 2 so that the strimp
402 : * will be recreated.
403 : *
404 : * This function returns true if at the end we have a valid pointer.
405 : */
406 : static bool
407 834 : BATcheckstrimps(BAT *b)
408 : {
409 834 : bool ret;
410 834 : lng t = GDKusec();
411 :
412 834 : if (b == NULL)
413 : return false;
414 :
415 834 : assert(b->batCacheid > 0);
416 :
417 834 : if (b->tstrimps == (Strimps *)1) {
418 1 : Strimps *hp;
419 1 : const char *nme = BBP_physical(b->batCacheid);
420 1 : int fd;
421 :
422 1 : MT_thread_setalgorithm("read strimp index from disk");
423 :
424 1 : b->tstrimps = NULL;
425 1 : if ((hp = GDKzalloc(sizeof(Strimps))) != NULL &&
426 1 : (hp->strimps.farmid = BBPselectfarm(b->batRole, b->ttype, strimpheap)) >= 0) {
427 1 : strconcat_len(hp->strimps.filename,
428 : sizeof(hp->strimps.filename),
429 : nme, ".tstrimps", NULL);
430 1 : hp->strimps.parentid = b->batCacheid;
431 :
432 : /* check whether a persisted strimp can be found */
433 1 : if ((fd = GDKfdlocate(hp->strimps.farmid, nme, "rb+", "tstrimps")) >= 0) {
434 1 : struct stat st;
435 1 : uint64_t desc;
436 1 : size_t npairs;
437 1 : size_t hsize;
438 : /* Read the 8 byte long strimp
439 : * descriptor.
440 : *
441 : * HSIZE must be between 200 and
442 : * 584 (inclusive): 8 bytes the
443 : * descriptor, 64 bytes the pair
444 : * sizes and n*64 bytes the
445 : * actual pairs where 2 <= n <=
446 : * 8.
447 : */
448 1 : if (read(fd, &desc, 8) == 8
449 1 : && (desc & 0xff) == STRIMP_VERSION
450 1 : && ((npairs = NPAIRS(desc)) == STRIMP_PAIRS)
451 1 : && (hsize = HSIZE(desc)) >= 200 && hsize <= 584
452 1 : && ((desc >> 32) & 0xff) == 1 /* check the persistence byte */
453 1 : && fstat(fd, &st) == 0
454 : /* TODO: We might need padding in the UTF-8 case. */
455 1 : && st.st_size >= (off_t) (hp->strimps.free = hp->strimps.size =
456 : /* header size (desc + offsets + pairs) */
457 1 : hsize +
458 : /* bitmasks */
459 1 : BATcount(b)*sizeof(uint64_t))
460 1 : && HEAPload(&hp->strimps, nme, "tstrimps", false) == GDK_SUCCEED) {
461 1 : hp->sizes_base = (uint8_t *)hp->strimps.base + 8; /* sizes just after the descriptor */
462 1 : hp->pairs_base = hp->sizes_base + STRIMP_HEADER_SIZE; /* pairs just after the offsets. */
463 1 : hp->bitstrings_base = hp->strimps.base + hsize; /* bitmasks just after the pairs */
464 1 : hp->masks = (strimp_masks_t *)GDKzalloc(STRIMP_HISTSIZE*sizeof(strimp_masks_t));
465 1 : if (hp->masks != NULL) {
466 : /* init */
467 : size_t offset = 0;
468 64 : for (size_t idx = 0; idx < STRIMP_PAIRS; idx++) {
469 63 : strimp_masks_t mask = ((strimp_masks_t)0x1) << (STRIMP_PAIRS - idx - 1);
470 63 : uint8_t pair_size = hp->sizes_base[idx];
471 63 : uint8_t *pair = hp->pairs_base + offset;
472 :
473 63 : size_t i = bytes2histindex(pair, pair_size);
474 63 : STRMPset_mask(hp, i, mask);
475 :
476 63 : offset += pair_size;
477 :
478 : }
479 :
480 1 : close(fd);
481 1 : ATOMIC_INIT(&hp->strimps.refs, 1);
482 1 : b->tstrimps = hp;
483 1 : hp->strimps.hasfile = true;
484 1 : TRC_DEBUG(ACCELERATOR, "BATcheckstrimps(" ALGOBATFMT "): reusing persisted strimp\n", ALGOBATPAR(b));
485 1 : return true;
486 : }
487 : /* We failed to allocate the
488 : * masks field. In principle we
489 : * can try to re-create the
490 : * strimp from scratch.
491 : */
492 : }
493 0 : close(fd);
494 : /* unlink unusable file */
495 0 : GDKunlink(hp->strimps.farmid, BATDIR, nme, "tstrimps");
496 0 : hp->strimps.hasfile = false;
497 :
498 : }
499 : }
500 : /* For some reason the index exists but was not read
501 : * correctly from disk. Set the pointer to the value 2
502 : * to signify that it needs to be recreated.
503 : */
504 0 : b->tstrimps = (Strimps *)2;
505 0 : GDKfree(hp);
506 0 : GDKclrerr(); /* we're not currently interested in errors */
507 : }
508 :
509 833 : ret = b->tstrimps != NULL && b->tstrimps != (Strimps *)2;
510 833 : if (ret) {
511 828 : TRC_DEBUG(ACCELERATOR,
512 : "BATcheckstrimps(" ALGOBATFMT "): already has strimps, waited " LLFMT " usec\n",
513 : ALGOBATPAR(b), GDKusec() - t);
514 : }
515 :
516 : return ret;
517 : }
518 :
519 : #define STRMPfilterloop(next) \
520 : do { \
521 : for (i = 0; i < ci.ncand; i++) { \
522 : x = next(&ci); \
523 : if ((bitstring_array[x] & qbmask) == qbmask || \
524 : (keep_nils && (bitstring_array[x] & ((uint64_t)0x1 << (STRIMP_HEADER_SIZE - 1))))) { \
525 : rvals[j++] = x; \
526 : } \
527 : } \
528 : } while (0)
529 :
530 : /* Filter a slice of a BAT b as defined by a candidate list s using a
531 : * string q. Return the result as a candidate list.
532 : *
533 : * This function also takes a boolean that controls its behavior with
534 : * respect to nil values. It should be true only for NOT LIKE queries
535 : * and in that case the nil values get included in the result. Later we
536 : * will take the complement and the nil values will be dropped from the
537 : * final result.
538 : */
539 : BAT *
540 828 : STRMPfilter(BAT *b, BAT *s, const char *q, const bool keep_nils)
541 : {
542 828 : BAT *r = NULL;
543 828 : BUN i, j = 0;
544 828 : uint64_t qbmask;
545 828 : uint64_t *bitstring_array;
546 828 : Strimps *strmps;
547 828 : oid x, *restrict rvals;
548 828 : struct canditer ci;
549 828 : lng t0 = 0;
550 828 : BAT *pb;
551 :
552 828 : TRC_DEBUG_IF(ACCELERATOR) t0 = GDKusec();
553 :
554 828 : if (VIEWtparent(b)) {
555 828 : pb = BATdescriptor(VIEWtparent(b));
556 827 : if (pb == NULL)
557 : return NULL;
558 : }
559 : else {
560 : pb = b;
561 : }
562 :
563 827 : MT_lock_set(&pb->batIdxLock);
564 828 : if (!BATcheckstrimps(pb)) {
565 0 : MT_lock_unset(&pb->batIdxLock);
566 0 : goto sfilter_fail;
567 : }
568 828 : strmps = pb->tstrimps;
569 828 : STRMPincref(strmps);
570 828 : MT_lock_unset(&pb->batIdxLock);
571 :
572 828 : canditer_init(&ci, b, s);
573 828 : if (ci.ncand == 0) {
574 0 : STRMPdecref(strmps, false);
575 0 : r = BATdense(b->hseqbase, 0, 0);
576 0 : if (pb != b)
577 0 : BBPunfix(pb->batCacheid);
578 0 : return r;
579 : }
580 828 : r = COLnew(b->hseqbase, TYPE_oid, ci.ncand, TRANSIENT);
581 828 : if (r == NULL) {
582 0 : STRMPdecref(strmps, false);
583 0 : goto sfilter_fail;
584 : }
585 :
586 828 : qbmask = STRMPmakebitstring(q, strmps);
587 828 : assert((qbmask & ((uint64_t)0x1 << (STRIMP_HEADER_SIZE - 1))) == 0);
588 828 : TRC_DEBUG(ACCELERATOR, "strimp filtering with pattern '%s' bitmap: %#016" PRIx64 "\n",
589 : q, qbmask);
590 828 : bitstring_array = (uint64_t *)strmps->bitstrings_base;
591 828 : rvals = Tloc(r, 0);
592 :
593 828 : if (ci.tpe == cand_dense) {
594 156128 : STRMPfilterloop(canditer_next_dense);
595 : } else {
596 0 : STRMPfilterloop(canditer_next);
597 : }
598 :
599 828 : BATsetcount(r, j);
600 828 : r->tkey = true;
601 828 : r->tsorted = true;
602 828 : r->trevsorted = BATcount(r) <= 1;
603 828 : r->tnil = false;
604 828 : r->tnonil = true;
605 828 : TRC_DEBUG(ACCELERATOR, "strimp prefiltering of " BUNFMT
606 : " items took " LLFMT " usec. Keeping " BUNFMT
607 : " items (%.2f%%).\n",
608 : ci.ncand, GDKusec()-t0, r->batCount,
609 : 100*r->batCount/(double)ci.ncand);
610 828 : TRC_DEBUG(ACCELERATOR, "r->" ALGOBATFMT "\n", ALGOBATPAR(r) );
611 828 : STRMPdecref(strmps, false);
612 828 : if (pb != b)
613 828 : BBPunfix(pb->batCacheid);
614 828 : return virtualize(r);
615 :
616 0 : sfilter_fail:
617 0 : if (pb != b)
618 0 : BBPunfix(pb->batCacheid);
619 : return NULL;
620 : }
621 :
622 : /* Write the strimp to disk */
623 : static void
624 5 : BATstrimpsync(BAT *b)
625 : {
626 5 : lng t0 = 0;
627 5 : Heap *hp;
628 5 : int fd;
629 5 : const char *failed = " failed";
630 :
631 5 : TRC_DEBUG_IF(ACCELERATOR) t0 = GDKusec();
632 :
633 5 : if ((hp = &b->tstrimps->strimps)) {
634 5 : if (HEAPsave(hp, hp->filename, NULL, true, hp->free, NULL) == GDK_SUCCEED) {
635 5 : if (hp->storage == STORE_MEM) {
636 3 : if ((fd = GDKfdlocate(hp->farmid, hp->filename, "rb+", NULL)) >= 0) {
637 3 : ((uint64_t *)hp->base)[0] |= (uint64_t) 1 << 32;
638 3 : if (write(fd, hp->base, sizeof(uint64_t)) >= 0) {
639 3 : failed = "";
640 3 : if (!(ATOMIC_GET(&GDKdebug) & NOSYNCMASK)) {
641 : #if defined(NATIVE_WIN32)
642 : _commit(fd);
643 : #elif defined(HAVE_FDATASYNC)
644 0 : fdatasync(fd);
645 : #elif defined(HAVE_FSYNC)
646 : fsync(fd);
647 : #endif
648 : }
649 3 : hp->dirty = false;
650 : } else {
651 0 : perror("write strimps");
652 : }
653 3 : close(fd);
654 : }
655 : } else {
656 2 : ((uint64_t *)hp->base)[0] |= (uint64_t) 1 << 32;
657 2 : if (!(ATOMIC_GET(&GDKdebug) & NOSYNCMASK) &&
658 0 : MT_msync(hp->base, sizeof(uint64_t)) < 0) {
659 0 : ((uint64_t *)hp->base)[0] &= ~((uint64_t) 1 << 32);
660 : } else {
661 2 : hp->dirty = false;
662 2 : failed = "";
663 : }
664 : }
665 5 : TRC_DEBUG(ACCELERATOR, "BATstrimpsync(%s): strimp persisted"
666 : " (" LLFMT " usec)%s\n",
667 : BATgetId(b), GDKusec() - t0, failed);
668 : }
669 : }
670 5 : BBPunfix(b->batCacheid);
671 5 : }
672 :
673 : /* Perform some checks to see if it makes sense to persist the strimp
674 : * and if so call the routine that writes the strimp to disk.
675 : */
676 : static void
677 5 : persistStrimp(BAT *b)
678 : {
679 5 : if((BBP_status(b->batCacheid) & BBPEXISTING)
680 5 : && b->batInserted == b->batCount
681 5 : && !b->theap->dirty
682 10 : && !GDKinmemory(b->theap->farmid)) {
683 5 : BBPfix(b->batCacheid);
684 5 : char name[MT_NAME_LEN];
685 5 : snprintf(name, sizeof(name), "strimpsync%d", b->batCacheid);
686 5 : BATstrimpsync(b);
687 : } else
688 0 : TRC_DEBUG(ACCELERATOR, "persistStrimp(" ALGOBATFMT "): NOT persisting strimp\n", ALGOBATPAR(b));
689 5 : }
690 :
691 :
692 : /* This function calls all the necessary routines to create the strimp
693 : * header, allocates enough space for the heap and encodes the header.
694 : * It returns NULL if anything fails.
695 : *
696 : */
697 : static Strimps *
698 5 : STRMPcreateStrimpHeap(BAT *b, BAT *s)
699 : {
700 5 : uint8_t *h1, *h2;
701 5 : Strimps *r = NULL;
702 5 : uint64_t descriptor;
703 5 : size_t i;
704 5 : uint16_t sz;
705 5 : CharPair *hpairs = (CharPair*)GDKzalloc(sizeof(CharPair)*STRIMP_HEADER_SIZE);
706 5 : const char *nme;
707 :
708 5 : if (!hpairs)
709 : return NULL;
710 :
711 10 : if ((r = b->tstrimps) == NULL &&
712 5 : STRMPbuildHeader(b, s, hpairs)) { /* Find the header pairs, put
713 : the result in hpairs */
714 : /* The 64th bit in the bit string is used to indicate if
715 : the string is NULL. So the corresponding pair does
716 : not encode useful information. We need to keep it for
717 : alignment but we must make sure that it will not
718 : match an actual pair of characters we encounter in
719 : strings.*/
720 15 : for (i = 0; i < hpairs[STRIMP_HEADER_SIZE - 1].psize; i++)
721 10 : hpairs[STRIMP_HEADER_SIZE - 1].pbytes[i] = 0;
722 : sz = 8 + STRIMP_HEADER_SIZE; /* add 8-bytes for the descriptor and
723 : the pair sizes */
724 325 : for (i = 0; i < STRIMP_HEADER_SIZE; i++) {
725 320 : sz += hpairs[i].psize;
726 : }
727 :
728 5 : nme = GDKinmemory(b->theap->farmid) ? ":memory:"
729 5 : : BBP_physical(b->batCacheid);
730 : /* Allocate the strimps heap */
731 5 : if ((r = GDKzalloc(sizeof(Strimps))) == NULL ||
732 5 : (r->strimps.farmid =
733 5 : BBPselectfarm(b->batRole, b->ttype, strimpheap)) < 0 ||
734 10 : (r->strimps.parentid = b->batCacheid) <= 0 ||
735 5 : strconcat_len(r->strimps.filename, sizeof(r->strimps.filename),
736 : nme, ".tstrimps",
737 5 : NULL) >= sizeof(r->strimps.filename) ||
738 5 : HEAPalloc(&r->strimps, BATcount(b) * sizeof(uint64_t) + sz,
739 : sizeof(uint8_t)) != GDK_SUCCEED) {
740 0 : GDKfree(r);
741 0 : GDKfree(hpairs);
742 0 : return NULL;
743 : }
744 :
745 5 : if ((r->masks = (strimp_masks_t *)GDKzalloc(STRIMP_HISTSIZE*sizeof(strimp_masks_t))) == NULL) {
746 0 : HEAPfree(&r->strimps, true);
747 0 : GDKfree(r);
748 0 : return NULL;
749 : }
750 :
751 320 : for (size_t i = 0; i < STRIMP_PAIRS; i++) {
752 315 : r->masks[hpairs[i].idx] = hpairs[i].mask;
753 : }
754 :
755 5 : descriptor = STRIMP_VERSION | ((uint64_t)(STRIMP_PAIRS)) << 8 |
756 5 : ((uint64_t)sz) << 16;
757 :
758 5 : ((uint64_t *)r->strimps.base)[0] = descriptor;
759 5 : r->sizes_base = h1 = (uint8_t *)r->strimps.base + 8;
760 5 : r->pairs_base = h2 = (uint8_t *)h1 + STRIMP_HEADER_SIZE;
761 :
762 325 : for (i = 0; i < STRIMP_HEADER_SIZE; i++) {
763 320 : uint8_t psize = hpairs[i].psize;
764 320 : h1[i] = psize;
765 320 : memcpy(h2, hpairs[i].pbytes, psize);
766 320 : h2 += psize;
767 : }
768 5 : r->bitstrings_base = h2;
769 5 : r->strimps.free = sz;
770 5 : r->rec_cnt = 0;
771 5 : ATOMIC_INIT(&r->strimps.refs, 1);
772 : }
773 5 : GDKfree(hpairs);
774 5 : return r;
775 : }
776 :
777 : /* Check if there is a strimp index for the given BAT.
778 : */
779 : bool
780 4622 : BAThasstrimps(BAT *b)
781 : {
782 4622 : BAT *pb;
783 4622 : bool ret;
784 4622 : if (VIEWtparent(b)) {
785 3706 : pb = BATdescriptor(VIEWtparent(b));
786 3706 : assert(pb);
787 : } else {
788 : pb = b;
789 : }
790 :
791 4622 : MT_lock_set(&pb->batIdxLock);
792 4631 : ret = pb->tstrimps != NULL;
793 4631 : MT_lock_unset(&pb->batIdxLock);
794 :
795 4631 : if (pb != b)
796 3706 : BBPunfix(pb->batCacheid);
797 4631 : return ret;
798 :
799 : }
800 :
801 : /* Signal strimp creation. The SQL layer uses this function to notify
802 : * the kernel that a strimp index should be created for this BAT. The
803 : * only way that this might fail is if the BAT is not large enough.
804 : */
805 : gdk_return
806 6 : BATsetstrimps(BAT *b)
807 : {
808 6 : BAT *pb;
809 6 : if (VIEWtparent(b)) {
810 0 : pb = BATdescriptor(VIEWtparent(b));
811 0 : assert(pb);
812 : } else {
813 : pb = b;
814 : }
815 :
816 6 : if (pb->batCount < STRIMP_CREATION_THRESHOLD) {
817 0 : GDKerror("Cannot create strimps index on columns with fewer than " BUNFMT " elements\n", STRIMP_CREATION_THRESHOLD);
818 0 : if (pb != b)
819 0 : BBPunfix(pb->batCacheid);
820 0 : return GDK_FAIL;
821 : }
822 :
823 :
824 6 : MT_lock_set(&pb->batIdxLock);
825 6 : if (pb->tstrimps == NULL) {
826 6 : pb->tstrimps = (Strimps *)2;
827 : }
828 6 : MT_lock_unset(&pb->batIdxLock);
829 :
830 6 : if (pb != b)
831 0 : BBPunfix(pb->batCacheid);
832 : return GDK_SUCCEED;
833 : }
834 :
835 : /* This macro takes a bat and checks if the strimp construction has been
836 : * completed. It is completed when it is an actual pointer and the
837 : * number of bitstrings computed is the same as the number of elements
838 : * in the BAT.
839 : */
840 : #define STRIMP_COMPLETE(b) \
841 : ((b)->tstrimps != NULL && \
842 : (b)->tstrimps != (Strimps *)1 && \
843 : (b)->tstrimps != (Strimps *)2 && \
844 : (((b)->tstrimps->strimps.free - ((char *)(b)->tstrimps->bitstrings_base - (b)->tstrimps->strimps.base)) == (b)->batCount*sizeof(uint64_t)))
845 :
846 :
847 : /* Strimp creation.
848 : *
849 : * First we attempt to take the index lock of the BAT. The first thread
850 : * that succeeds, checks if the strimp already exists on disk and
851 : * attempts to read it. If this succeeds then strimp creation is
852 : * complete. If it does not either because the strimp does not exist or
853 : * because it is outdated (if for example there is a version mismatch),
854 : * the same thread that still holds the lock attempts to create the
855 : * strimp header and heap. If this fails then we cannot have a strimp on
856 : * this BAT and we report a failure after releasing the lock.
857 : *
858 : * If the strimp header is successfully created, then we release the
859 : * lock and allow the rest of the threads to compute the bitstrings of
860 : * the slice they have been assigned.
861 : *
862 : */
863 : gdk_return
864 36 : STRMPcreate(BAT *b, BAT *s)
865 : {
866 36 : lng t0 = 0;
867 36 : BAT *pb;
868 36 : Strimps *r = NULL;
869 36 : BATiter bi;
870 36 : BUN i;
871 36 : oid x;
872 36 : struct canditer ci;
873 36 : uint64_t *dh;
874 :
875 36 : TRC_DEBUG_IF(ACCELERATOR) t0 = GDKusec();
876 36 : TRC_DEBUG(ACCELERATOR, "creating strimp");
877 36 : if (ATOMstorage(b->ttype) != TYPE_str) {
878 0 : GDKerror("Cannot create strimps index for non string bats\n");
879 0 : return GDK_FAIL;
880 : }
881 :
882 36 : if (VIEWtparent(b)) {
883 36 : pb = BATdescriptor(VIEWtparent(b));
884 36 : assert(pb);
885 : } else {
886 : pb = b;
887 : }
888 :
889 : /* First thread to take the lock will read the strimp from disk
890 : * or construct the strimp header.
891 : */
892 36 : MT_lock_set(&pb->batIdxLock);
893 :
894 : /* Strimp creation was requested. There are three cases:
895 : * - The strimp is on disk (pb->tstrimps == 1)
896 : * - The strimp needs to be created (pb->tstrimps == 2)
897 : * - Finally the pointer might have been changed to NULL in another thread.
898 : */
899 36 : if (pb->tstrimps == NULL || pb->tstrimps == (Strimps*)1 || pb->tstrimps == (Strimps*)2) {
900 : /* The strimp needs to be created. The rest of the
901 : * creation code assumes that the pointer to the strimps
902 : * is NULL. Make it so.
903 : */
904 6 : if (pb->tstrimps == (Strimps *)2)
905 5 : pb->tstrimps = NULL;
906 6 : if (pb->tstrimps == NULL || pb->tstrimps == (Strimps*)1) {
907 6 : if (BATcheckstrimps(pb)) {
908 1 : MT_lock_unset(&pb->batIdxLock);
909 1 : if (pb != b)
910 1 : BBPunfix(pb->batCacheid);
911 1 : return GDK_SUCCEED;
912 : }
913 :
914 : /* BATcheckstrimps, might set the pointer to 2.
915 : * Set it to NULL so that strimp creation will
916 : * proceed as if the strimp has never existed.
917 : */
918 5 : if (pb->tstrimps == (Strimps *)2)
919 0 : pb->tstrimps = NULL;
920 :
921 5 : assert(pb->tstrimps == NULL);
922 :
923 5 : if ((r = STRMPcreateStrimpHeap(pb, s)) == NULL) {
924 : /* Strimp creation failed, but it still
925 : * exists in the SQL layer. Set the
926 : * pointer to 2 so that construction
927 : * will be attempted again next time.
928 : */
929 0 : pb->tstrimps = (Strimps *)2;
930 0 : MT_lock_unset(&pb->batIdxLock);
931 0 : if (pb != b)
932 0 : BBPunfix(pb->batCacheid);
933 0 : return GDK_FAIL;
934 : }
935 5 : pb->tstrimps = r;
936 : }
937 : }
938 :
939 35 : if (STRIMP_COMPLETE(pb)) {
940 15 : MT_lock_unset(&pb->batIdxLock);
941 15 : if (pb != b)
942 15 : BBPunfix(pb->batCacheid);
943 15 : return GDK_SUCCEED;
944 : }
945 :
946 : /* At this point pb->tstrimps should be a valid strimp heap. */
947 20 : assert(pb->tstrimps);
948 20 : MT_thread_setalgorithm("create strimp index");
949 20 : r = pb->tstrimps;
950 20 : STRMPincref(r);
951 20 : if (pb != b) {
952 20 : MT_lock_unset(&pb->batIdxLock);
953 20 : MT_lock_set(&b->batIdxLock);
954 : }
955 20 : dh = (uint64_t *)r->bitstrings_base + b->hseqbase;
956 20 : canditer_init(&ci, b, s);
957 :
958 20 : bi = bat_iterator(b);
959 65405 : for (i = 0; i < ci.ncand; i++) {
960 65365 : x = canditer_next(&ci) - b->hseqbase;
961 63164 : const char *cs = BUNtvar(bi, x);
962 125656 : if (!strNil(cs))
963 61920 : *dh++ = STRMPmakebitstring(cs, r);
964 : else
965 908 : *dh++ = (uint64_t)0x1 << (STRIMP_HEADER_SIZE - 1); /* Encode NULL strings in the most significant bit */
966 : }
967 20 : bat_iterator_end(&bi);
968 :
969 20 : if (pb != b) {
970 20 : MT_lock_unset(&b->batIdxLock);
971 20 : MT_lock_set(&pb->batIdxLock);
972 : }
973 20 : r->strimps.free += b->batCount*sizeof(uint64_t);
974 : /* The thread that reaches this point last needs to write the strimp to disk. */
975 20 : if ((r->strimps.free - ((char *)r->bitstrings_base - r->strimps.base)) == b->batCount*sizeof(uint64_t)) {
976 5 : persistStrimp(pb);
977 : }
978 20 : MT_lock_unset(&pb->batIdxLock);
979 20 : STRMPdecref(r, false);
980 :
981 20 : TRC_DEBUG(ACCELERATOR, "strimp creation took " LLFMT " usec\n", GDKusec()-t0);
982 20 : if (pb != b)
983 20 : BBPunfix(pb->batCacheid);
984 : return GDK_SUCCEED;
985 : }
986 :
987 :
988 : void
989 854 : STRMPdecref(Strimps *strimps, bool remove)
990 : {
991 854 : if (remove)
992 2 : ATOMIC_OR(&strimps->strimps.refs, HEAPREMOVE);
993 854 : ATOMIC_BASE_TYPE refs = ATOMIC_DEC(&strimps->strimps.refs);
994 854 : TRC_DEBUG(ACCELERATOR, "Decrement ref count of %s to " BUNFMT "\n",
995 : strimps->strimps.filename, (BUN) (refs & HEAPREFS));
996 854 : if ((refs & HEAPREFS) == 0) {
997 6 : HEAPfree(&strimps->strimps, (bool) (refs & HEAPREMOVE));
998 6 : GDKfree(strimps->masks);
999 6 : GDKfree(strimps);
1000 : }
1001 :
1002 854 : }
1003 :
1004 : void
1005 848 : STRMPincref(Strimps *strimps)
1006 : {
1007 848 : ATOMIC_BASE_TYPE refs = ATOMIC_INC(&strimps->strimps.refs);
1008 848 : TRC_DEBUG(ACCELERATOR, "Increment ref count of %s to " BUNFMT "\n",
1009 : strimps->strimps.filename, (BUN) (refs & HEAPREFS));
1010 848 : }
1011 :
1012 : void
1013 77145732 : STRMPdestroy(BAT *b)
1014 : {
1015 77145732 : if (b) {
1016 77145732 : MT_lock_set(&b->batIdxLock);
1017 77122919 : if (b->tstrimps == (Strimps *)1) {
1018 0 : b->tstrimps = NULL;
1019 0 : GDKunlink(BBPselectfarm(b->batRole, b->ttype, strimpheap),
1020 : BATDIR,
1021 0 : BBP_physical(b->batCacheid),
1022 : "tstrimps");
1023 77122919 : } else if (b->tstrimps == (Strimps *)2) {
1024 0 : b->tstrimps = NULL;
1025 77122919 : } else if (b->tstrimps != NULL) {
1026 2 : STRMPdecref(b->tstrimps, b->tstrimps->strimps.parentid == b->batCacheid);
1027 2 : b->tstrimps = NULL;
1028 : }
1029 77122919 : MT_lock_unset(&b->batIdxLock);
1030 : }
1031 77133090 : }
1032 :
1033 : void
1034 354235 : STRMPfree(BAT *b)
1035 : {
1036 354235 : if (b) {
1037 354235 : Strimps *s;
1038 354235 : MT_lock_set(&b->batIdxLock);
1039 354235 : if ((s = b->tstrimps) != NULL && s != (Strimps *)1 && s != (Strimps *)2) {
1040 4 : if (GDKinmemory(s->strimps.farmid)) {
1041 0 : b->tstrimps = NULL;
1042 0 : STRMPdecref(s, s->strimps.parentid == b->batCacheid);
1043 : }
1044 : else {
1045 4 : if (s->strimps.parentid == b->batCacheid)
1046 4 : b->tstrimps = (Strimps *)1;
1047 : else
1048 0 : b->tstrimps = NULL;
1049 4 : STRMPdecref(s, false);
1050 : }
1051 :
1052 : }
1053 354235 : MT_lock_unset(&b->batIdxLock);
1054 : }
1055 354235 : }
1056 :
1057 : #if 0
1058 : /* Update the strimp by computing a bitstring and adding it to the heap.
1059 : This will probably be useful later when strimps take updates into
1060 : account. */
1061 : gdk_return
1062 : STRMPappendBitstring(BAT *b, const char *s)
1063 : {
1064 : lng t0 = 0;
1065 : BAT *pb;
1066 : uint64_t *dh;
1067 : Strimps *strmp;
1068 : const float extend_factor = 1.5;
1069 :
1070 : TRC_DEBUG_IF(ACCELERATOR) t0 = GDKusec();
1071 : if (ATOMstorage(b->ttype) != TYPE_str) {
1072 : GDKerror("Cannot manipulate strimps index for non string bats\n");
1073 : return GDK_FAIL;
1074 : }
1075 :
1076 : if (VIEWtparent(b)) {
1077 : pb = BATdescriptor(VIEWtparent(b));
1078 : assert(pb);
1079 : } else {
1080 : pb = b;
1081 : }
1082 :
1083 : if (!BATcheckstrimps(pb)) {
1084 : GDKerror("Strimp missing, cannot append value\n");
1085 : if (pb != b)
1086 : BBPunfix(pb->batCacheid);
1087 : return GDK_FAIL;
1088 : }
1089 : MT_lock_set(&pb->batIdxLock);
1090 : strmp = pb->tstrimps;
1091 : /* Extend heap if there is not enough space */
1092 : if (strmp->strimps.free >= strmp->strimps.size + sizeof(uint64_t)) {
1093 : size_t sizes_offset = (char *)strmp->sizes_base - strmp->strimps.base;
1094 : size_t pairs_offset = (char *)strmp->pairs_base - strmp->strimps.base;
1095 : size_t bitstrings_offset = (char *)strmp->bitstrings_base - strmp->strimps.base;
1096 : if (HEAPextend(&(strmp->strimps), (size_t)(extend_factor*BATcount(pb)*sizeof(uint64_t)), false) != GDK_SUCCEED) {
1097 : MT_lock_unset(&pb->batIdxLock);
1098 : GDKerror("Cannot extend heap\n");
1099 : if (pb != b)
1100 : BBPunfix(pb->batCacheid);
1101 : return GDK_FAIL;
1102 : }
1103 : strmp->sizes_base = (uint8_t *)strmp->strimps.base + sizes_offset;
1104 : strmp->pairs_base = (uint8_t *)strmp->strimps.base + pairs_offset;
1105 : strmp->bitstrings_base = strmp->strimps.base + bitstrings_offset;
1106 : }
1107 : dh = (uint64_t *)strmp->strimps.base + pb->tstrimps->strimps.free;
1108 : *dh = STRMPmakebitstring(s, strmp);
1109 : strmp->strimps.free += sizeof(uint64_t);
1110 :
1111 : strmp->rec_cnt++;
1112 : MT_lock_unset(&pb->batIdxLock);
1113 :
1114 : TRC_DEBUG(ACCELERATOR, "appending to strimp took " LLFMT " usec\n", GDKusec()-t0);
1115 : if (pb != b)
1116 : BBPunfix(pb->batCacheid);
1117 : return GDK_SUCCEED;
1118 : }
1119 : #endif
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