diff options
| -rw-r--r-- | src/backend/access/heap/tuptoaster.c | 122 | ||||
| -rw-r--r-- | src/backend/commands/cluster.c | 4 |
2 files changed, 117 insertions, 9 deletions
diff --git a/src/backend/access/heap/tuptoaster.c b/src/backend/access/heap/tuptoaster.c index 4f4dd69291f..0ce04a57275 100644 --- a/src/backend/access/heap/tuptoaster.c +++ b/src/backend/access/heap/tuptoaster.c @@ -74,7 +74,9 @@ do { \ static void toast_delete_datum(Relation rel, Datum value); -static Datum toast_save_datum(Relation rel, Datum value, int options); +static Datum toast_save_datum(Relation rel, Datum value, + struct varlena *oldexternal, int options); +static bool toast_valueid_exists(Oid toastrelid, Oid valueid); static struct varlena *toast_fetch_datum(struct varlena * attr); static struct varlena *toast_fetch_datum_slice(struct varlena * attr, int32 sliceoffset, int32 length); @@ -431,6 +433,7 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup, bool toast_oldisnull[MaxHeapAttributeNumber]; Datum toast_values[MaxHeapAttributeNumber]; Datum toast_oldvalues[MaxHeapAttributeNumber]; + struct varlena *toast_oldexternal[MaxHeapAttributeNumber]; int32 toast_sizes[MaxHeapAttributeNumber]; bool toast_free[MaxHeapAttributeNumber]; bool toast_delold[MaxHeapAttributeNumber]; @@ -466,6 +469,7 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup, * ---------- */ memset(toast_action, ' ', numAttrs * sizeof(char)); + memset(toast_oldexternal, 0, numAttrs * sizeof(struct varlena *)); memset(toast_free, 0, numAttrs * sizeof(bool)); memset(toast_delold, 0, numAttrs * sizeof(bool)); @@ -550,6 +554,7 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup, */ if (VARATT_IS_EXTERNAL(new_value)) { + toast_oldexternal[i] = new_value; if (att[i]->attstorage == 'p') new_value = heap_tuple_untoast_attr(new_value); else @@ -676,7 +681,8 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup, { old_value = toast_values[i]; toast_action[i] = 'p'; - toast_values[i] = toast_save_datum(rel, toast_values[i], options); + toast_values[i] = toast_save_datum(rel, toast_values[i], + toast_oldexternal[i], options); if (toast_free[i]) pfree(DatumGetPointer(old_value)); toast_free[i] = true; @@ -726,7 +732,8 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup, i = biggest_attno; old_value = toast_values[i]; toast_action[i] = 'p'; - toast_values[i] = toast_save_datum(rel, toast_values[i], options); + toast_values[i] = toast_save_datum(rel, toast_values[i], + toast_oldexternal[i], options); if (toast_free[i]) pfree(DatumGetPointer(old_value)); toast_free[i] = true; @@ -839,7 +846,8 @@ toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup, i = biggest_attno; old_value = toast_values[i]; toast_action[i] = 'p'; - toast_values[i] = toast_save_datum(rel, toast_values[i], options); + toast_values[i] = toast_save_datum(rel, toast_values[i], + toast_oldexternal[i], options); if (toast_free[i]) pfree(DatumGetPointer(old_value)); toast_free[i] = true; @@ -1117,10 +1125,16 @@ toast_compress_datum(Datum value) * * Save one single datum into the secondary relation and return * a Datum reference for it. + * + * rel: the main relation we're working with (not the toast rel!) + * value: datum to be pushed to toast storage + * oldexternal: if not NULL, toast pointer previously representing the datum + * options: options to be passed to heap_insert() for toast rows * ---------- */ static Datum -toast_save_datum(Relation rel, Datum value, int options) +toast_save_datum(Relation rel, Datum value, + struct varlena *oldexternal, int options) { Relation toastrel; Relation toastidx; @@ -1199,11 +1213,55 @@ toast_save_datum(Relation rel, Datum value, int options) toast_pointer.va_toastrelid = RelationGetRelid(toastrel); /* - * Choose an unused OID within the toast table for this toast value. + * Choose an OID to use as the value ID for this toast value. + * + * Normally we just choose an unused OID within the toast table. But + * during table-rewriting operations where we are preserving an existing + * toast table OID, we want to preserve toast value OIDs too. So, if + * rd_toastoid is set and we had a prior external value from that same + * toast table, re-use its value ID. If we didn't have a prior external + * value (which is a corner case, but possible if the table's attstorage + * options have been changed), we have to pick a value ID that doesn't + * conflict with either new or existing toast value OIDs. */ - toast_pointer.va_valueid = GetNewOidWithIndex(toastrel, - RelationGetRelid(toastidx), - (AttrNumber) 1); + if (!OidIsValid(rel->rd_toastoid)) + { + /* normal case: just choose an unused OID */ + toast_pointer.va_valueid = + GetNewOidWithIndex(toastrel, + RelationGetRelid(toastidx), + (AttrNumber) 1); + } + else + { + /* rewrite case: check to see if value was in old toast table */ + toast_pointer.va_valueid = InvalidOid; + if (oldexternal != NULL) + { + struct varatt_external old_toast_pointer; + + Assert(VARATT_IS_EXTERNAL(oldexternal)); + /* Must copy to access aligned fields */ + VARATT_EXTERNAL_GET_POINTER(old_toast_pointer, oldexternal); + if (old_toast_pointer.va_toastrelid == rel->rd_toastoid) + toast_pointer.va_valueid = old_toast_pointer.va_valueid; + } + if (toast_pointer.va_valueid == InvalidOid) + { + /* + * new value; must choose an OID that doesn't conflict in either + * old or new toast table + */ + do + { + toast_pointer.va_valueid = + GetNewOidWithIndex(toastrel, + RelationGetRelid(toastidx), + (AttrNumber) 1); + } while (toast_valueid_exists(rel->rd_toastoid, + toast_pointer.va_valueid)); + } + } /* * Initialize constant parts of the tuple data @@ -1339,6 +1397,52 @@ toast_delete_datum(Relation rel, Datum value) /* ---------- + * toast_valueid_exists - + * + * Test whether a toast value with the given ID exists in the toast relation + * ---------- + */ +static bool +toast_valueid_exists(Oid toastrelid, Oid valueid) +{ + bool result = false; + Relation toastrel; + ScanKeyData toastkey; + SysScanDesc toastscan; + + /* + * Open the toast relation + */ + toastrel = heap_open(toastrelid, AccessShareLock); + + /* + * Setup a scan key to find chunks with matching va_valueid + */ + ScanKeyInit(&toastkey, + (AttrNumber) 1, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(valueid)); + + /* + * Is there any such chunk? + */ + toastscan = systable_beginscan(toastrel, toastrel->rd_rel->reltoastidxid, + true, SnapshotToast, 1, &toastkey); + + if (systable_getnext(toastscan) != NULL) + result = true; + + /* + * End scan and close relations + */ + systable_endscan(toastscan); + heap_close(toastrel, AccessShareLock); + + return result; +} + + +/* ---------- * toast_fetch_datum - * * Reconstruct an in memory Datum from the chunks saved diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c index 9a7649bb4f9..670d29ea831 100644 --- a/src/backend/commands/cluster.c +++ b/src/backend/commands/cluster.c @@ -797,6 +797,10 @@ copy_heap_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex, * When doing swap by content, any toast pointers written into NewHeap * must use the old toast table's OID, because that's where the toast * data will eventually be found. Set this up by setting rd_toastoid. + * This also tells tuptoaster.c to preserve the toast value OIDs, + * which we want so as not to invalidate toast pointers in system + * catalog caches. + * * Note that we must hold NewHeap open until we are done writing data, * since the relcache will not guarantee to remember this setting once * the relation is closed. Also, this technique depends on the fact |