MonetDB: string_imprints - Use candidate lists for strimps

[Panagiotis Koutsourakis]

Changeset: 3d18e45d5375 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/3d18e45d5375
Modified Files:
        gdk/gdk_strimps.c
Branch: string_imprints
Log Message:

Use candidate lists for strimps

We use candidate lists both for strimp creation and for filtering.


diffs (136 lines):

diff --git a/gdk/gdk_strimps.c b/gdk/gdk_strimps.c
--- a/gdk/gdk_strimps.c
+++ b/gdk/gdk_strimps.c
@@ -242,20 +242,25 @@ STRMPbuildHeader(BAT *b, BAT *s, CharPai
        lng t0 = 0;
        BATiter bi;
        str cs;
-       BUN i;
+       BUN i, ncand;
        size_t hidx;
+       oid x;
        size_t hlen;
        PairHistogramElem *hist;
        PairIterator pi, *pip;
        CharPair cp, *cpp;
+       struct canditer ci;
 
-       (void)s;
 
        TRC_DEBUG_IF(ACCELERATOR) t0 = GDKusec();
        hlen = STRIMP_HISTSIZE;
        if ((hist = (PairHistogramElem 
*)GDKmalloc(hlen*sizeof(PairHistogramElem))) == NULL) {
-               // TODO handle error
-               return 0;
+               return false;
+       }
+
+       ncand = canditer_init(&ci, b, s);
+       if (ncand == 0) {
+               return false;
        }
 
        for(hidx = 0; hidx < hlen; hidx++) {
@@ -267,8 +272,9 @@ STRMPbuildHeader(BAT *b, BAT *s, CharPai
        bi = bat_iterator(b);
        pip = &pi;
        cpp = &cp;
-       for (i = 0; i < b->batCount; i++) {
-               cs = (str)BUNtvar(bi, i);
+       for (i = 0; i < ncand; i++) {
+               x = canditer_next(&ci) - b->hseqbase;
+               cs = (str)BUNtvar(bi, x);
                if (!strNil(cs)) {
                        pi.s = cs;
                        pi.pos = 0;
@@ -339,8 +345,8 @@ STRMPcreateStrimpHeap(BAT *b, BAT *s)
        if (b->tstrimps == NULL) {
                MT_lock_set(&b->batIdxLock);
                /* Make sure no other thread got here first */
-                if (b->tstrimps == NULL) {
-                       STRMPbuildHeader(b, s, hpairs); /* Find the header 
pairs */
+                if (b->tstrimps == NULL &&
+                   STRMPbuildHeader(b, s, hpairs)) { /* Find the header pairs, 
put the result in hpairs */
                        sz = 8 + STRIMP_HEADER_SIZE; /* add 8-bytes for the 
descriptor and the pair sizes */
                        for (i = 0; i < STRIMP_HEADER_SIZE; i++) {
                                sz += hpairs[i].psize;
@@ -464,14 +470,14 @@ BAT *
 STRMPfilter(BAT *b, BAT *s, char *q)
 {
        BAT *r = NULL;
-       BUN i;
+       BUN i, ncand;
        uint64_t qbmask;
        uint64_t *ptr;
        Strimps *strmps;
-       (void)s;
+       oid x;
+       struct canditer ci;
 
        if (isVIEW(b)) {
-               // b = BBP_cache(VIEWtparent(b));
                BAT *pb = BBP_cache(VIEWtparent(b));
                if (!BATcheckstrimps(pb))
                        goto sfilter_fail;
@@ -483,17 +489,27 @@ STRMPfilter(BAT *b, BAT *s, char *q)
                strmps = b->tstrimps;
        }
 
-       r = COLnew(b->hseqbase, TYPE_oid, b->batCount, TRANSIENT);
+       ncand = canditer_init(&ci, b, s);
+       if (ncand == 0)
+               /* Is this correct? */
+               return BATdense(b->hseqbase, 0, 0);
+       r = COLnew(b->hseqbase, TYPE_oid, ncand, TRANSIENT);
        if (r == NULL) {
                goto sfilter_fail;
        }
 
+       /* TODO: Compare patterns with and without SQL pattern metachars
+        * (% and _). Theoretically they should produce the same results
+        * because bitstring creation ignores punctuation characters
+        * (see the macro isIgnored).
+        */
        qbmask = STRMPmakebitstring(q, strmps);
        ptr = (uint64_t *)strmps->strimps_base;
 
-       for (i = 0; i < b->batCount; i++) {
-               if ((*(ptr + i) & qbmask) == qbmask) {
-                       oid pos = i + b->hseqbase;
+       for (i = 0; i < ncand; i++) {
+               x = canditer_next(&ci) - b->hseqbase;
+               if ((*(ptr + x) & qbmask) == qbmask) {
+                       oid pos = x + b->hseqbase;
                        if (BUNappend(r, &pos, false) != GDK_SUCCEED)
                                goto sfilter_fail;
                }
@@ -590,11 +606,13 @@ STRMPcreate(BAT *b, BAT *s)
 {
        lng t0 = 0;
        BATiter bi;
-       BUN i;
+       BUN i, ncand;
        str cs;
        Strimps *h;
        uint64_t *dh;
        BAT *pb;
+       oid x;
+       struct canditer ci;
 
        TRC_DEBUG_IF(ACCELERATOR) t0 = GDKusec();
        if (b->ttype != TYPE_str) {
@@ -619,9 +637,12 @@ STRMPcreate(BAT *b, BAT *s)
        }
        dh = (uint64_t *)((uint8_t*)h->strimps.base + h->strimps.free + 
b->hseqbase*8);
 
+       ncand = canditer_init(&ci, b, s);
+
        bi = bat_iterator(b);
-       for (i = 0; i < bi.count; i++) {
-               cs = (str)BUNtvar(bi, i);
+       for (i = 0; i < ncand; i++) {
+               x = canditer_next(&ci) - b->hseqbase;
+               cs = (str)BUNtvar(bi, x);
                if (!strNil(cs))
                        *dh++ = STRMPmakebitstring(cs, h);
                else
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