diff options
Diffstat (limited to 'src/backend/access/heap/tuptoaster.c')
| -rw-r--r-- | src/backend/access/heap/tuptoaster.c | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/src/backend/access/heap/tuptoaster.c b/src/backend/access/heap/tuptoaster.c index a40cfcf1954..74e957abb72 100644 --- a/src/backend/access/heap/tuptoaster.c +++ b/src/backend/access/heap/tuptoaster.c @@ -75,6 +75,7 @@ static struct varlena *toast_fetch_datum(struct varlena *attr); static struct varlena *toast_fetch_datum_slice(struct varlena *attr, int32 sliceoffset, int32 length); static struct varlena *toast_decompress_datum(struct varlena *attr); +static struct varlena *toast_decompress_datum_slice(struct varlena *attr, int32 slicelength); static int toast_open_indexes(Relation toastrel, LOCKMODE lock, Relation **toastidxs, @@ -301,7 +302,11 @@ heap_tuple_untoast_attr_slice(struct varlena *attr, { struct varlena *tmp = preslice; - preslice = toast_decompress_datum(tmp); + /* Decompress enough to encompass the slice and the offset */ + if (slicelength > 0 && sliceoffset >= 0) + preslice = toast_decompress_datum_slice(tmp, slicelength + sliceoffset); + else + preslice = toast_decompress_datum(tmp); if (tmp != attr) pfree(tmp); @@ -2272,9 +2277,38 @@ toast_decompress_datum(struct varlena *attr) if (pglz_decompress(TOAST_COMPRESS_RAWDATA(attr), VARSIZE(attr) - TOAST_COMPRESS_HDRSZ, VARDATA(result), - TOAST_COMPRESS_RAWSIZE(attr)) < 0) + TOAST_COMPRESS_RAWSIZE(attr), true) < 0) + elog(ERROR, "compressed data is corrupted"); + + return result; +} + + +/* ---------- + * toast_decompress_datum_slice - + * + * Decompress the front of a compressed version of a varlena datum. + * offset handling happens in heap_tuple_untoast_attr_slice. + * Here we just decompress a slice from the front. + */ +static struct varlena * +toast_decompress_datum_slice(struct varlena *attr, int32 slicelength) +{ + struct varlena *result; + int32 rawsize; + + Assert(VARATT_IS_COMPRESSED(attr)); + + result = (struct varlena *) palloc(slicelength + VARHDRSZ); + + rawsize = pglz_decompress(TOAST_COMPRESS_RAWDATA(attr), + VARSIZE(attr) - TOAST_COMPRESS_HDRSZ, + VARDATA(result), + slicelength, false); + if (rawsize < 0) elog(ERROR, "compressed data is corrupted"); + SET_VARSIZE(result, rawsize + VARHDRSZ); return result; } |