Tweak GiST code to work correctly on machines where 8-byte alignment

of pointers is required.  Patch from Teodor Sigaev per pghackers
discussion.  It's an ugly kluge but avoids forcing initdb; we'll put
a better fix into 7.3 or later.

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index db57a5f..1ce1914 100644 (file)
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/access/gist/gist.c,v 1.87 2002/01/15 22:14:16 tgl Exp $
+ *       $Header: /cvsroot/pgsql/src/backend/access/gist/gist.c,v 1.88 2002/02/11 22:41:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -659,6 +659,7 @@ gistunion(Relation r, IndexTuple *itvec, int len, GISTSTATE *giststate)
        Datum           attr[INDEX_MAX_KEYS];
        bool            whatfree[INDEX_MAX_KEYS];
        char            isnull[INDEX_MAX_KEYS];
+       char       *storage;
        bytea      *evec;
        Datum           datum;
        int                     datumsize,
@@ -671,7 +672,9 @@ gistunion(Relation r, IndexTuple *itvec, int len, GISTSTATE *giststate)
        int                     reallen;
 
        needfree = (bool *) palloc(((len == 1) ? 2 : len) * sizeof(bool));
-       evec = (bytea *) palloc(((len == 1) ? 2 : len) * sizeof(GISTENTRY) + VARHDRSZ);
+       /* workaround for 64-bit: ensure GISTENTRY array is maxaligned */
+       storage = (char*)palloc( ((len == 1) ? 2 : len) * sizeof(GISTENTRY) + MAXALIGN(VARHDRSZ));
+       evec = (bytea *) (storage + MAXALIGN(VARHDRSZ) - VARHDRSZ);
 
        for (j = 0; j < r->rd_att->natts; j++)
        {
@@ -737,7 +740,7 @@ gistunion(Relation r, IndexTuple *itvec, int len, GISTSTATE *giststate)
                }
        }
 
-       pfree(evec);
+       pfree(storage);                         /* pfree(evec); */
        pfree(needfree);
 
        newtup = (IndexTuple) index_formtuple(giststate->tupdesc, attr, isnull);
@@ -772,11 +775,13 @@ gistgetadjusted(Relation r, IndexTuple oldtup, IndexTuple addtup, GISTSTATE *gis
                                adddec[INDEX_MAX_KEYS];
        bool            oldisnull[INDEX_MAX_KEYS],
                                addisnull[INDEX_MAX_KEYS];
-
        IndexTuple      newtup = NULL;
+       char       *storage;
        int                     j;
 
-       evec = (bytea *) palloc(2 * sizeof(GISTENTRY) + VARHDRSZ);
+       /* workaround for 64-bit: ensure GISTENTRY array is maxaligned */
+       storage = (char*) palloc( 2 * sizeof(GISTENTRY) + MAXALIGN(VARHDRSZ));
+       evec = (bytea *) (storage + MAXALIGN(VARHDRSZ) - VARHDRSZ);
        VARATT_SIZEP(evec) = 2 * sizeof(GISTENTRY) + VARHDRSZ;
        ev0p = &((GISTENTRY *) VARDATA(evec))[0];
        ev1p = &((GISTENTRY *) VARDATA(evec))[1];
@@ -844,7 +849,7 @@ gistgetadjusted(Relation r, IndexTuple oldtup, IndexTuple addtup, GISTSTATE *gis
                                whatfree[j] = FALSE;
                }
        }
-       pfree(evec);
+       pfree(storage);                         /* pfree(evec); */
 
        if (neednew)
        {
@@ -873,6 +878,7 @@ gistunionsubkey(Relation r, GISTSTATE *giststate, IndexTuple *itvec, GIST_SPLITV
                           *attrsize;
        OffsetNumber *entries;
        bytea      *evec;
+       char       *storage;
        Datum           datum;
        int                     datumsize;
        int                     reallen;
@@ -898,7 +904,10 @@ gistunionsubkey(Relation r, GISTSTATE *giststate, IndexTuple *itvec, GIST_SPLITV
                }
 
                needfree = (bool *) palloc(((len == 1) ? 2 : len) * sizeof(bool));
-               evec = (bytea *) palloc(((len == 1) ? 2 : len) * sizeof(GISTENTRY) + VARHDRSZ);
+               /* workaround for 64-bit: ensure GISTENTRY array is maxaligned */
+               storage = (char*)palloc( ((len == 1) ? 2 : len) * sizeof(GISTENTRY) + MAXALIGN(VARHDRSZ));
+               evec = (bytea *) (storage + MAXALIGN(VARHDRSZ) - VARHDRSZ);
+
                for (j = 1; j < r->rd_att->natts; j++)
                {
                        reallen = 0;
@@ -958,7 +967,7 @@ gistunionsubkey(Relation r, GISTSTATE *giststate, IndexTuple *itvec, GIST_SPLITV
                        attr[j] = datum;
                        attrsize[j] = datumsize;
                }
-               pfree(evec);
+               pfree(storage);                 /* pfree(evec); */
                pfree(needfree);
        }
 }
@@ -1050,6 +1059,7 @@ gistadjsubkey(Relation r,
        float           lpenalty,
                                rpenalty;
        bytea      *evec;
+       char       *storage;
        int                     datumsize;
        bool            isnull[INDEX_MAX_KEYS];
        int                     i,
@@ -1081,7 +1091,9 @@ gistadjsubkey(Relation r,
                        curlen--;
        v->spl_nright = curlen;
 
-       evec = (bytea *) palloc(2 * sizeof(GISTENTRY) + VARHDRSZ);
+       /* workaround for 64-bit: ensure GISTENTRY array is maxaligned */
+       storage = (char*)palloc( 2 * sizeof(GISTENTRY) + MAXALIGN(VARHDRSZ));
+       evec = (bytea *) (storage + MAXALIGN(VARHDRSZ) - VARHDRSZ);
        VARATT_SIZEP(evec) = 2 * sizeof(GISTENTRY) + VARHDRSZ;
        ev0p = &((GISTENTRY *) VARDATA(evec))[0];
        ev1p = &((GISTENTRY *) VARDATA(evec))[1];
@@ -1189,7 +1201,7 @@ gistadjsubkey(Relation r,
                }
                gistFreeAtt(r, identry, decfree);
        }
-       pfree(evec);
+       pfree(storage);                         /* pfree(evec); */
 }
 
 /*
@@ -1216,6 +1228,7 @@ gistSplit(Relation r,
        GISTPageOpaque opaque;
        GIST_SPLITVEC v;
        bytea      *entryvec;
+       char       *storage;
        bool       *decompvec;
        int                     i,
                                j,
@@ -1227,7 +1240,6 @@ gistSplit(Relation r,
        p = (Page) BufferGetPage(buffer);
        opaque = (GISTPageOpaque) PageGetSpecialPointer(p);
 
-
        /*
         * The root of the tree is the first block in the relation.  If we're
         * about to split the root, we need to do some hocus-pocus to enforce
@@ -1255,8 +1267,10 @@ gistSplit(Relation r,
        right = (Page) BufferGetPage(rightbuf);
 
        /* generate the item array */
-       entryvec = (bytea *) palloc(VARHDRSZ + (*len + 1) * sizeof(GISTENTRY));
-       decompvec = (bool *) palloc(VARHDRSZ + (*len + 1) * sizeof(bool));
+       /* workaround for 64-bit: ensure GISTENTRY array is maxaligned */
+       storage = palloc(MAXALIGN(VARHDRSZ) + (*len + 1) * sizeof(GISTENTRY));
+       entryvec = (bytea *) (storage + MAXALIGN(VARHDRSZ) - VARHDRSZ);
+       decompvec = (bool *) palloc( (*len + 1) * sizeof(bool));
        VARATT_SIZEP(entryvec) = (*len + 1) * sizeof(GISTENTRY) + VARHDRSZ;
        for (i = 1; i <= *len; i++)
        {
@@ -1322,7 +1336,7 @@ gistSplit(Relation r,
        for (i = 1; i <= *len; i++)
                if (decompvec[i])
                        pfree(DatumGetPointer(((GISTENTRY *) VARDATA(entryvec))[i].key));
-       pfree(entryvec);
+       pfree(storage);                         /* pfree(entryvec); */
        pfree(decompvec);
 
        /* form left and right vector */