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 db57a5f3ffaa3b4a87fa236745688deca20cca25..1ce1914304b319f8ae4394fd1e1ad3ab7e8440cf 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 */