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Overview
Comment:Simplify the computation of descendants using a recursive CTE.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 31fcde837d45500d8681f4660ca4f7a06e3ef509
User & Date: drh 2015-05-24 00:53:37
Context
2015-05-25
09:52
Close <a> tag, as reported by Svyatoslav Mishyn check-in: d10b1e02 user: jan.nijtmans tags: trunk
2015-05-24
00:53
Simplify the computation of descendants using a recursive CTE. check-in: 31fcde83 user: drh tags: trunk
2015-05-23
18:12
Fix harmless compiler warnings. check-in: e3560443 user: mistachkin tags: trunk
Changes
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Changes to src/descendants.c.

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}

/*
** Load the record ID rid and up to N-1 closest descendants into
** the "ok" table.
*/
void compute_descendants(int rid, int N){
  Bag seen;
  PQueue queue;
  Stmt ins;
  Stmt q;


  bag_init(&seen);
  pqueuex_init(&queue);
  bag_insert(&seen, rid);
  pqueuex_insert(&queue, rid, 0.0, 0);
  db_prepare(&ins, "INSERT OR IGNORE INTO ok VALUES(:rid)");
  db_prepare(&q, "SELECT cid, mtime FROM plink WHERE pid=:rid");
  while( (N--)>0 && (rid = pqueuex_extract(&queue, 0))!=0 ){
    db_bind_int(&ins, ":rid", rid);
    db_step(&ins);
    db_reset(&ins);
    db_bind_int(&q, ":rid", rid);
    while( db_step(&q)==SQLITE_ROW ){
      int pid = db_column_int(&q, 0);
      double mtime = db_column_double(&q, 1);
      if( bag_insert(&seen, pid) ){
        pqueuex_insert(&queue, pid, mtime, 0);
      }
    }
    db_reset(&q);
  }
  bag_clear(&seen);
  pqueuex_clear(&queue);
  db_finalize(&ins);
  db_finalize(&q);
}

/*
** COMMAND: descendants*
**
** Usage: %fossil descendants ?CHECKIN? ?OPTIONS?
**







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}

/*
** Load the record ID rid and up to N-1 closest descendants into
** the "ok" table.
*/
void compute_descendants(int rid, int N){
  db_multi_exec(
    "WITH RECURSIVE"
    "  dx(rid,mtime) AS ("
    "     SELECT %d, 0"

    "     UNION"
    "     SELECT plink.cid, plink.mtime FROM dx, plink"
    "      WHERE plink.pid=dx.rid"
    "      ORDER BY 2"
    "  )"
    "INSERT OR IGNORE INTO ok SELECT rid FROM dx LIMIT %d",
    rid, N
  );

















}

/*
** COMMAND: descendants*
**
** Usage: %fossil descendants ?CHECKIN? ?OPTIONS?
**