liquid_feedback_core

view lf_update_issue_order.c @ 494:b4b660562322

Another bugfix in function "get_initiatives_for_notification"
author jbe
date Sun Apr 03 20:00:20 2016 +0200 (2016-04-03)
parents d301dc24b25c
children
line source
1 #include <stdlib.h>
2 #include <stdio.h>
3 #include <string.h>
4 #include <libpq-fe.h>
5 #include <search.h>
7 static int logging = 0;
9 static char *escapeLiteral(PGconn *conn, const char *str, size_t len) {
10 // provides compatibility for PostgreSQL versions prior 9.0
11 // in future: return PQescapeLiteral(conn, str, len);
12 char *res;
13 size_t res_len;
14 res = malloc(2*len+3);
15 if (!res) return NULL;
16 res[0] = '\'';
17 res_len = PQescapeStringConn(conn, res+1, str, len, NULL);
18 res[res_len+1] = '\'';
19 res[res_len+2] = 0;
20 return res;
21 }
23 static void freemem(void *ptr) {
24 // to be used for "escapeLiteral" function
25 // provides compatibility for PostgreSQL versions prior 9.0
26 // in future: PQfreemem(ptr);
27 free(ptr);
28 }
30 // column numbers when querying "issue_supporter_in_admission_state" view in function main():
31 #define COL_MEMBER_ID 0
32 #define COL_WEIGHT 1
33 #define COL_ISSUE_ID 2
35 // data structure for a candidate (in this case an issue) to the proportional runoff system:
36 struct candidate {
37 char *key; // identifier of the candidate, which is the "issue_id" string
38 double score_per_step; // added score per step
39 double score; // current score of candidate; a score of 1.0 is needed to survive a round
40 int seat; // equals 0 for unseated candidates, or contains rank number
41 };
43 // compare two integers stored as strings (invocation like strcmp):
44 static int compare_id(char *id1, char *id2) {
45 int ldiff;
46 ldiff = strlen(id1) - strlen(id2);
47 if (ldiff) return ldiff;
48 else return strcmp(id1, id2);
49 }
51 // compare two candidates by their key (invocation like strcmp):
52 static int compare_candidate(struct candidate *c1, struct candidate *c2) {
53 return compare_id(c1->key, c2->key);
54 }
56 // candidates are stored as global variables due to the constrained twalk() interface:
57 static int candidate_count;
58 static struct candidate *candidates;
60 // function to be passed to twalk() to store candidates ordered in candidates[] array:
61 static void register_candidate(char **candidate_key, VISIT visit, int level) {
62 if (visit == postorder || visit == leaf) {
63 struct candidate *candidate;
64 candidate = candidates + (candidate_count++);
65 candidate->key = *candidate_key;
66 candidate->seat = 0;
67 if (logging) printf("Candidate #%i is issue #%s.\n", candidate_count, candidate->key);
68 }
69 }
71 // performs a binary search in candidates[] array to lookup a candidate by its key (which is the issue_id):
72 static struct candidate *candidate_by_key(char *candidate_key) {
73 struct candidate *candidate;
74 struct candidate compare;
75 compare.key = candidate_key;
76 candidate = bsearch(&compare, candidates, candidate_count, sizeof(struct candidate), (void *)compare_candidate);
77 if (!candidate) {
78 fprintf(stderr, "Candidate not found (should not happen).\n");
79 abort();
80 }
81 return candidate;
82 }
84 // ballot of the proportional runoff system, containing only one preference section:
85 struct ballot {
86 int weight; // if weight is greater than 1, then the ballot is counted multiple times
87 int count; // number of candidates
88 struct candidate **candidates; // all candidates equally preferred
89 };
91 // determine candidate, which is assigned the next seat (starting with the worst rank):
92 static struct candidate *loser(int round_number, struct ballot *ballots, int ballot_count) {
93 int i, j; // index variables for loops
94 int remaining; // remaining candidates to be seated
95 // reset scores of all candidates:
96 for (i=0; i<candidate_count; i++) {
97 candidates[i].score = 0.0;
98 }
99 // calculate remaining candidates to be seated:
100 remaining = candidate_count - round_number;
101 // repeat following loop, as long as there is more than one remaining candidate:
102 while (remaining > 1) {
103 if (logging) printf("There are %i remaining candidates.\n", remaining);
104 double scale; // factor to be later multiplied with score_per_step:
105 // reset score_per_step for all candidates:
106 for (i=0; i<candidate_count; i++) {
107 candidates[i].score_per_step = 0.0;
108 }
109 // calculate score_per_step for all candidates:
110 for (i=0; i<ballot_count; i++) {
111 int matches = 0;
112 for (j=0; j<ballots[i].count; j++) {
113 struct candidate *candidate;
114 candidate = ballots[i].candidates[j];
115 if (candidate->score < 1.0 && !candidate->seat) matches++;
116 }
117 if (matches) {
118 double score_inc;
119 score_inc = (double)ballots[i].weight / (double)matches;
120 for (j=0; j<ballots[i].count; j++) {
121 struct candidate *candidate;
122 candidate = ballots[i].candidates[j];
123 if (candidate->score < 1.0 && !candidate->seat) {
124 candidate->score_per_step += score_inc;
125 }
126 }
127 }
128 }
129 // calculate scale factor:
130 scale = (double)0.0; // 0.0 is used to indicate that there is no value yet
131 for (i=0; i<candidate_count; i++) {
132 double max_scale;
133 if (candidates[i].score_per_step > 0.0) {
134 max_scale = (1.0-candidates[i].score) / candidates[i].score_per_step;
135 if (scale == 0.0 || max_scale <= scale) {
136 scale = max_scale;
137 }
138 }
139 }
140 // add scale*score_per_step to each candidates score:
141 for (i=0; i<candidate_count; i++) {
142 int log_candidate = 0;
143 if (logging && candidates[i].score < 1.0 && !candidates[i].seat) log_candidate = 1;
144 if (log_candidate) printf("Score for issue #%s = %.4f+%.4f*%.4f", candidates[i].key, candidates[i].score, scale, candidates[i].score_per_step);
145 if (candidates[i].score_per_step > 0.0) {
146 double max_scale;
147 max_scale = (1.0-candidates[i].score) / candidates[i].score_per_step;
148 if (max_scale == scale) {
149 // score of 1.0 should be reached, so we set score directly to avoid floating point errors:
150 candidates[i].score = 1.0;
151 remaining--;
152 } else {
153 candidates[i].score += scale * candidates[i].score_per_step;
154 if (candidates[i].score >= 1.0) remaining--;
155 }
156 }
157 if (log_candidate) {
158 if (candidates[i].score >= 1.0) printf("=1\n");
159 else printf("=%.4f\n", candidates[i].score);
160 }
161 // when there is only one candidate remaining, then break inner (and thus outer) loop:
162 if (remaining <= 1) {
163 break;
164 }
165 }
166 }
167 // return remaining candidate:
168 for (i=0; i<candidate_count; i++) {
169 if (candidates[i].score < 1.0 && !candidates[i].seat) return candidates+i;
170 }
171 // if there is no remaining candidate, then something went wrong:
172 fprintf(stderr, "No remaining candidate (should not happen).");
173 abort();
174 }
176 // write results to database:
177 static int write_ranks(PGconn *db, char *escaped_area_or_unit_id, char *mode) {
178 PGresult *res;
179 char *cmd;
180 int i;
181 res = PQexec(db, "BEGIN");
182 if (!res) {
183 fprintf(stderr, "Error in pqlib while sending SQL command to initiate issue order update.\n");
184 return 1;
185 } else if (
186 PQresultStatus(res) != PGRES_COMMAND_OK &&
187 PQresultStatus(res) != PGRES_TUPLES_OK
188 ) {
189 fprintf(stderr, "Error while executing SQL command to initiate issue order update:\n%s", PQresultErrorMessage(res));
190 PQclear(res);
191 return 1;
192 } else {
193 PQclear(res);
194 }
195 for (i=0; i<candidate_count; i++) {
196 char *escaped_issue_id;
197 escaped_issue_id = escapeLiteral(db, candidates[i].key, strlen(candidates[i].key));
198 if (!escaped_issue_id) {
199 fprintf(stderr, "Could not escape literal in memory.\n");
200 abort();
201 }
202 if (asprintf(&cmd, "UPDATE \"issue_order_in_admission_state\" SET \"order_in_%s\" = %i WHERE \"id\" = %s", mode, candidates[i].seat, escaped_issue_id) < 0) {
203 fprintf(stderr, "Could not prepare query string in memory.\n");
204 abort();
205 }
206 freemem(escaped_issue_id);
207 res = PQexec(db, cmd);
208 free(cmd);
209 if (!res) {
210 fprintf(stderr, "Error in pqlib while sending SQL command to update issue order.\n");
211 } else if (
212 PQresultStatus(res) != PGRES_COMMAND_OK &&
213 PQresultStatus(res) != PGRES_TUPLES_OK
214 ) {
215 fprintf(stderr, "Error while executing SQL command to update issue order:\n%s", PQresultErrorMessage(res));
216 PQclear(res);
217 } else {
218 PQclear(res);
219 continue;
220 }
221 res = PQexec(db, "ROLLBACK");
222 if (res) PQclear(res);
223 return 1;
224 }
225 res = PQexec(db, "COMMIT");
226 if (!res) {
227 fprintf(stderr, "Error in pqlib while sending SQL command to commit transaction.\n");
228 return 1;
229 } else if (
230 PQresultStatus(res) != PGRES_COMMAND_OK &&
231 PQresultStatus(res) != PGRES_TUPLES_OK
232 ) {
233 fprintf(stderr, "Error while executing SQL command to commit transaction:\n%s", PQresultErrorMessage(res));
234 PQclear(res);
235 return 1;
236 } else {
237 PQclear(res);
238 }
239 return 0;
240 }
242 // calculate ordering of issues in admission state for an area and call write_ranks() to write it to database:
243 static int process_area_or_unit(PGconn *db, PGresult *res, char *escaped_area_or_unit_id, char *mode) {
244 int err; // variable to store an error condition (0 = success)
245 int ballot_count = 1; // number of ballots, must be initiatized to 1, due to loop below
246 struct ballot *ballots; // data structure containing the ballots
247 int i; // index variable for loops
248 // create candidates[] and ballots[] arrays:
249 {
250 void *candidate_tree = NULL; // temporary structure to create a sorted unique list of all candidate keys
251 int tuple_count; // number of tuples returned from the database
252 char *old_member_id = NULL; // old member_id to be able to detect a new ballot in loops
253 struct ballot *ballot; // pointer to current ballot
254 int candidates_in_ballot = 0; // number of candidates in ballot
255 // reset candidate count:
256 candidate_count = 0;
257 // determine number of tuples:
258 tuple_count = PQntuples(res);
259 // trivial case, when there are no tuples:
260 if (!tuple_count) {
261 // write results to database:
262 if (logging) printf("No supporters for any issue. Writing ranks to database.\n");
263 err = write_ranks(db, escaped_area_or_unit_id, mode);
264 if (logging) printf("Done.\n");
265 return 0;
266 }
267 // calculate ballot_count and generate set of candidate keys (issue_id is used as key):
268 for (i=0; i<tuple_count; i++) {
269 char *member_id, *issue_id;
270 member_id = PQgetvalue(res, i, COL_MEMBER_ID);
271 issue_id = PQgetvalue(res, i, COL_ISSUE_ID);
272 if (!candidate_tree || !tfind(issue_id, &candidate_tree, (void *)compare_id)) {
273 candidate_count++;
274 if (!tsearch(issue_id, &candidate_tree, (void *)compare_id)) {
275 fprintf(stderr, "Insufficient memory while inserting into candidate tree.\n");
276 abort();
277 }
278 }
279 if (old_member_id && strcmp(old_member_id, member_id)) ballot_count++;
280 old_member_id = member_id;
281 }
282 // allocate memory for candidates[] array:
283 candidates = malloc(candidate_count * sizeof(struct candidate));
284 if (!candidates) {
285 fprintf(stderr, "Insufficient memory while creating candidate list.\n");
286 abort();
287 }
288 // transform tree of candidate keys into sorted array:
289 candidate_count = 0; // needed by register_candidate()
290 twalk(candidate_tree, (void *)register_candidate);
291 // free memory of tree structure (tdestroy() is not available on all platforms):
292 while (candidate_tree) tdelete(*(void **)candidate_tree, &candidate_tree, (void *)compare_id);
293 // allocate memory for ballots[] array:
294 ballots = calloc(ballot_count, sizeof(struct ballot));
295 if (!ballots) {
296 fprintf(stderr, "Insufficient memory while creating ballot list.\n");
297 abort();
298 }
299 // set ballot weights, determine ballot section sizes, and verify preference values:
300 ballot = ballots;
301 old_member_id = NULL;
302 for (i=0; i<tuple_count; i++) {
303 char *member_id;
304 int weight;
305 member_id = PQgetvalue(res, i, COL_MEMBER_ID);
306 weight = (int)strtol(PQgetvalue(res, i, COL_WEIGHT), (char **)NULL, 10);
307 if (weight <= 0) {
308 fprintf(stderr, "Unexpected weight value.\n");
309 free(ballots);
310 free(candidates);
311 return 1;
312 }
313 if (old_member_id && strcmp(old_member_id, member_id)) ballot++;
314 ballot->weight = weight;
315 ballot->count++;
316 old_member_id = member_id;
317 }
318 // allocate memory for ballot sections:
319 for (i=0; i<ballot_count; i++) {
320 if (ballots[i].count) {
321 ballots[i].candidates = malloc(ballots[i].count * sizeof(struct candidate *));
322 if (!ballots[i].candidates) {
323 fprintf(stderr, "Insufficient memory while creating ballot section.\n");
324 abort();
325 }
326 }
327 }
328 // fill ballot sections with candidate references:
329 old_member_id = NULL;
330 ballot = ballots;
331 for (i=0; i<tuple_count; i++) {
332 char *member_id, *issue_id;
333 member_id = PQgetvalue(res, i, COL_MEMBER_ID);
334 issue_id = PQgetvalue(res, i, COL_ISSUE_ID);
335 if (old_member_id && strcmp(old_member_id, member_id)) {
336 ballot++;
337 candidates_in_ballot = 0;
338 }
339 ballot->candidates[candidates_in_ballot++] = candidate_by_key(issue_id);
340 old_member_id = member_id;
341 }
342 // print ballots, if logging is enabled:
343 if (logging) {
344 for (i=0; i<ballot_count; i++) {
345 int j;
346 printf("Ballot #%i: ", i+1);
347 for (j=0; j<ballots[i].count; j++) {
348 if (!j) printf("issues ");
349 else printf(", ");
350 printf("#%s", ballots[i].candidates[j]->key);
351 }
352 // if (!j) printf("empty"); // should not happen
353 printf(".\n");
354 }
355 }
356 }
358 // calculate ranks based on constructed data structures:
359 for (i=0; i<candidate_count; i++) {
360 struct candidate *candidate = loser(i, ballots, ballot_count);
361 candidate->seat = candidate_count - i;
362 if (logging) printf("Assigning rank #%i to issue #%s.\n", candidate_count-i, candidate->key);
363 }
365 // free ballots[] array:
366 for (i=0; i<ballot_count; i++) {
367 // if (ballots[i].count) { // count should not be zero
368 free(ballots[i].candidates);
369 // }
370 }
371 free(ballots);
373 // write results to database:
374 if (logging) printf("Writing ranks to database.\n");
375 err = write_ranks(db, escaped_area_or_unit_id, mode);
376 if (logging) printf("Done.\n");
378 // free candidates[] array:
379 free(candidates);
381 // return error code of write_ranks() call
382 return err;
383 }
385 int main(int argc, char **argv) {
387 // variable declarations:
388 int err = 0;
389 int i, count;
390 char *conninfo;
391 PGconn *db;
392 PGresult *res;
394 // parse command line:
395 if (argc == 0) return 1;
396 if (argc == 1 || !strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) {
397 FILE *out;
398 out = argc == 1 ? stderr : stdout;
399 fprintf(out, "\n");
400 fprintf(out, "Usage: %s [-v|--verbose] <conninfo>\n", argv[0]);
401 fprintf(out, "\n");
402 fprintf(out, "<conninfo> is specified by PostgreSQL's libpq,\n");
403 fprintf(out, "see http://www.postgresql.org/docs/9.1/static/libpq-connect.html\n");
404 fprintf(out, "\n");
405 fprintf(out, "Example: %s dbname=liquid_feedback\n", argv[0]);
406 fprintf(out, "\n");
407 return argc == 1 ? 1 : 0;
408 }
409 {
410 size_t len = 0;
411 int argb = 1;
412 if (
413 argc >= 2 &&
414 (!strcmp(argv[1], "-v") || !strcmp(argv[1], "--verbose"))
415 ) {
416 argb = 2;
417 logging = 1;
418 }
419 for (i=argb; i<argc; i++) len += strlen(argv[i]) + 1;
420 conninfo = malloc(len * sizeof(char));
421 if (!conninfo) {
422 fprintf(stderr, "Error: Could not allocate memory for conninfo string.\n");
423 abort();
424 }
425 conninfo[0] = 0;
426 for (i=argb; i<argc; i++) {
427 if (i>argb) strcat(conninfo, " ");
428 strcat(conninfo, argv[i]);
429 }
430 }
432 // connect to database:
433 db = PQconnectdb(conninfo);
434 if (!db) {
435 fprintf(stderr, "Error: Could not create database handle.\n");
436 return 1;
437 }
438 if (PQstatus(db) != CONNECTION_OK) {
439 fprintf(stderr, "Could not open connection:\n%s", PQerrorMessage(db));
440 return 1;
441 }
443 // create missing "issue_order_in_admission_state" entries for issues
444 res = PQexec(db, "INSERT INTO \"issue_order_in_admission_state\" (\"id\") SELECT \"issue\".\"id\" FROM \"issue\" NATURAL LEFT JOIN \"issue_order_in_admission_state\" WHERE \"issue\".\"state\" = 'admission'::\"issue_state\" AND \"issue_order_in_admission_state\".\"id\" ISNULL");
445 if (!res) {
446 fprintf(stderr, "Error in pqlib while sending SQL command creating new issue order entries.\n");
447 err = 1;
448 } else if (
449 PQresultStatus(res) != PGRES_COMMAND_OK &&
450 PQresultStatus(res) != PGRES_TUPLES_OK
451 ) {
452 fprintf(stderr, "Error while executing SQL command creating new issue order entries:\n%s", PQresultErrorMessage(res));
453 err = 1;
454 PQclear(res);
455 } else {
456 if (logging) printf("Created %s new issue order entries.\n", PQcmdTuples(res));
457 PQclear(res);
458 }
460 // go through areas:
461 res = PQexec(db, "SELECT \"id\" FROM \"area\"");
462 if (!res) {
463 fprintf(stderr, "Error in pqlib while sending SQL command selecting areas to process.\n");
464 err = 1;
465 } else if (PQresultStatus(res) != PGRES_TUPLES_OK) {
466 fprintf(stderr, "Error while executing SQL command selecting areas to process:\n%s", PQresultErrorMessage(res));
467 err = 1;
468 PQclear(res);
469 } else if (PQnfields(res) < 1) {
470 fprintf(stderr, "Too few columns returned by SQL command selecting areas to process.\n");
471 err = 1;
472 PQclear(res);
473 } else {
474 count = PQntuples(res);
475 if (logging) printf("Number of areas to process: %i\n", count);
476 for (i=0; i<count; i++) {
477 char *area_id, *escaped_area_id;
478 char *cmd;
479 PGresult *res2;
480 area_id = PQgetvalue(res, i, 0);
481 if (logging) printf("Processing area #%s:\n", area_id);
482 escaped_area_id = escapeLiteral(db, area_id, strlen(area_id));
483 if (!escaped_area_id) {
484 fprintf(stderr, "Could not escape literal in memory.\n");
485 abort();
486 }
487 if (asprintf(&cmd, "SELECT \"member_id\", \"weight\", \"issue_id\" FROM \"issue_supporter_in_admission_state\" WHERE \"area_id\" = %s ORDER BY \"member_id\"", escaped_area_id) < 0) {
488 fprintf(stderr, "Could not prepare query string in memory.\n");
489 abort();
490 }
491 res2 = PQexec(db, cmd);
492 free(cmd);
493 if (!res2) {
494 fprintf(stderr, "Error in pqlib while sending SQL command selecting issue supporter in admission state.\n");
495 err = 1;
496 } else if (PQresultStatus(res2) != PGRES_TUPLES_OK) {
497 fprintf(stderr, "Error while executing SQL command selecting issue supporter in admission state:\n%s", PQresultErrorMessage(res));
498 err = 1;
499 PQclear(res2);
500 } else if (PQnfields(res2) < 3) {
501 fprintf(stderr, "Too few columns returned by SQL command selecting issue supporter in admission state.\n");
502 err = 1;
503 PQclear(res2);
504 } else {
505 if (process_area_or_unit(db, res2, escaped_area_id, "area")) err = 1;
506 PQclear(res2);
507 }
508 freemem(escaped_area_id);
509 }
510 PQclear(res);
511 }
513 // go through units:
514 res = PQexec(db, "SELECT \"id\" FROM \"unit\"");
515 if (!res) {
516 fprintf(stderr, "Error in pqlib while sending SQL command selecting units to process.\n");
517 err = 1;
518 } else if (PQresultStatus(res) != PGRES_TUPLES_OK) {
519 fprintf(stderr, "Error while executing SQL command selecting units to process:\n%s", PQresultErrorMessage(res));
520 err = 1;
521 PQclear(res);
522 } else if (PQnfields(res) < 1) {
523 fprintf(stderr, "Too few columns returned by SQL command selecting units to process.\n");
524 err = 1;
525 PQclear(res);
526 } else {
527 count = PQntuples(res);
528 if (logging) printf("Number of units to process: %i\n", count);
529 for (i=0; i<count; i++) {
530 char *unit_id, *escaped_unit_id;
531 char *cmd;
532 PGresult *res2;
533 unit_id = PQgetvalue(res, i, 0);
534 if (logging) printf("Processing unit #%s:\n", unit_id);
535 escaped_unit_id = escapeLiteral(db, unit_id, strlen(unit_id));
536 if (!escaped_unit_id) {
537 fprintf(stderr, "Could not escape literal in memory.\n");
538 abort();
539 }
540 if (asprintf(&cmd, "SELECT \"member_id\", \"weight\", \"issue_id\" FROM \"issue_supporter_in_admission_state\" WHERE \"unit_id\" = %s ORDER BY \"member_id\"", escaped_unit_id) < 0) {
541 fprintf(stderr, "Could not prepare query string in memory.\n");
542 abort();
543 }
544 res2 = PQexec(db, cmd);
545 free(cmd);
546 if (!res2) {
547 fprintf(stderr, "Error in pqlib while sending SQL command selecting issue supporter in admission state.\n");
548 err = 1;
549 } else if (PQresultStatus(res2) != PGRES_TUPLES_OK) {
550 fprintf(stderr, "Error while executing SQL command selecting issue supporter in admission state:\n%s", PQresultErrorMessage(res));
551 err = 1;
552 PQclear(res2);
553 } else if (PQnfields(res2) < 3) {
554 fprintf(stderr, "Too few columns returned by SQL command selecting issue supporter in admission state.\n");
555 err = 1;
556 PQclear(res2);
557 } else {
558 if (process_area_or_unit(db, res2, escaped_unit_id, "unit")) err = 1;
559 PQclear(res2);
560 }
561 freemem(escaped_unit_id);
562 }
563 PQclear(res);
564 }
566 // clean-up entries of deleted issues
567 res = PQexec(db, "DELETE FROM \"issue_order_in_admission_state\" USING \"issue_order_in_admission_state\" AS \"self\" NATURAL LEFT JOIN \"issue\" WHERE \"issue_order_in_admission_state\".\"id\" = \"self\".\"id\" AND (\"issue\".\"id\" ISNULL OR \"issue\".\"state\" != 'admission'::\"issue_state\")");
568 if (!res) {
569 fprintf(stderr, "Error in pqlib while sending SQL command deleting ordering data of deleted issues.\n");
570 err = 1;
571 } else if (
572 PQresultStatus(res) != PGRES_COMMAND_OK &&
573 PQresultStatus(res) != PGRES_TUPLES_OK
574 ) {
575 fprintf(stderr, "Error while executing SQL command deleting ordering data of deleted issues:\n%s", PQresultErrorMessage(res));
576 err = 1;
577 PQclear(res);
578 } else {
579 if (logging) printf("Cleaned up ordering data of %s deleted issues.\n", PQcmdTuples(res));
580 PQclear(res);
581 }
583 // cleanup and exit:
584 PQfinish(db);
585 if (!err) {
586 if (logging) printf("Successfully terminated.\n");
587 } else {
588 fprintf(stderr, "Exiting with error code %i.\n", err);
589 }
590 return err;
592 }

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