diff options
Diffstat (limited to 'src/backend/access/heap/tuptoaster.c')
| -rw-r--r-- | src/backend/access/heap/tuptoaster.c | 74 |
1 files changed, 34 insertions, 40 deletions
diff --git a/src/backend/access/heap/tuptoaster.c b/src/backend/access/heap/tuptoaster.c index fd20f111b80..99d725c27cc 100644 --- a/src/backend/access/heap/tuptoaster.c +++ b/src/backend/access/heap/tuptoaster.c @@ -8,14 +8,17 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.53 2005/10/15 02:49:09 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/access/heap/tuptoaster.c,v 1.54 2005/11/20 18:38:20 tgl Exp $ * * * INTERFACE ROUTINES - * heap_tuple_toast_attrs - + * toast_insert_or_update - * Try to make a given tuple fit into one page by compressing * or moving off attributes * + * toast_delete - + * Reclaim toast storage when a tuple is deleted + * * heap_tuple_untoast_attr - * Fetch back a given value from the "secondary" relation * @@ -40,10 +43,7 @@ #undef TOAST_DEBUG -static void toast_delete(Relation rel, HeapTuple oldtup); static void toast_delete_datum(Relation rel, Datum value); -static void toast_insert_or_update(Relation rel, HeapTuple newtup, - HeapTuple oldtup); static Datum toast_save_datum(Relation rel, Datum value); static varattrib *toast_fetch_datum(varattrib *attr); static varattrib *toast_fetch_datum_slice(varattrib *attr, @@ -51,24 +51,6 @@ static varattrib *toast_fetch_datum_slice(varattrib *attr, /* ---------- - * heap_tuple_toast_attrs - - * - * This is the central public entry point for toasting from heapam. - * - * Calls the appropriate event specific action. - * ---------- - */ -void -heap_tuple_toast_attrs(Relation rel, HeapTuple newtup, HeapTuple oldtup) -{ - if (newtup == NULL) - toast_delete(rel, oldtup); - else - toast_insert_or_update(rel, newtup, oldtup); -} - - -/* ---------- * heap_tuple_fetch_attr - * * Public entry point to get back a toasted value @@ -305,7 +287,7 @@ toast_datum_size(Datum value) * Cascaded delete toast-entries on DELETE * ---------- */ -static void +void toast_delete(Relation rel, HeapTuple oldtup) { TupleDesc tupleDesc; @@ -355,11 +337,22 @@ toast_delete(Relation rel, HeapTuple oldtup) * * Delete no-longer-used toast-entries and create new ones to * make the new tuple fit on INSERT or UPDATE + * + * Inputs: + * newtup: the candidate new tuple to be inserted + * oldtup: the old row version for UPDATE, or NULL for INSERT + * Result: + * either newtup if no toasting is needed, or a palloc'd modified tuple + * that is what should actually get stored + * + * NOTE: neither newtup nor oldtup will be modified. This is a change + * from the pre-8.1 API of this routine. * ---------- */ -static void +HeapTuple toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup) { + HeapTuple result_tuple; TupleDesc tupleDesc; Form_pg_attribute *att; int numAttrs; @@ -757,7 +750,7 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup) if (need_change) { HeapTupleHeader olddata = newtup->t_data; - char *new_data; + HeapTupleHeader new_data; int32 new_len; /* @@ -775,14 +768,18 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup) toast_values, toast_isnull); /* - * Allocate new tuple in same context as old one. + * Allocate and zero the space needed, and fill HeapTupleData fields. */ - new_data = (char *) MemoryContextAlloc(newtup->t_datamcxt, new_len); - newtup->t_data = (HeapTupleHeader) new_data; - newtup->t_len = new_len; + result_tuple = (HeapTuple) palloc0(HEAPTUPLESIZE + new_len); + result_tuple->t_len = new_len; + result_tuple->t_self = newtup->t_self; + result_tuple->t_tableOid = newtup->t_tableOid; + result_tuple->t_datamcxt = CurrentMemoryContext; + new_data = (HeapTupleHeader) ((char *) result_tuple + HEAPTUPLESIZE); + result_tuple->t_data = new_data; /* - * Put the tuple header and the changed values into place + * Put the existing tuple header and the changed values into place */ memcpy(new_data, olddata, olddata->t_hoff); @@ -790,16 +787,11 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup) toast_values, toast_isnull, (char *) new_data + olddata->t_hoff, - &(newtup->t_data->t_infomask), - has_nulls ? newtup->t_data->t_bits : NULL); - - /* - * In the case we modified a previously modified tuple again, free the - * memory from the previous run - */ - if ((char *) olddata != ((char *) newtup + HEAPTUPLESIZE)) - pfree(olddata); + &(new_data->t_infomask), + has_nulls ? new_data->t_bits : NULL); } + else + result_tuple = newtup; /* * Free allocated temp values @@ -816,6 +808,8 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup) for (i = 0; i < numAttrs; i++) if (toast_delold[i]) toast_delete_datum(rel, toast_oldvalues[i]); + + return result_tuple; } |