/*
* Write relation attributes to the stream.
*/
static void
logicalrep_write_attrs(StringInfo out, Relation rel)
{
TupleDesc desc;
int i;
uint16 nliveatts = 0;
Bitmapset *idattrs = NULL;
bool replidentfull;
desc = RelationGetDescr(rel);
/* send number of live attributes */
for (i = 0; i < desc->natts; i++)
{
if (TupleDescAttr(desc, i)->attisdropped)
continue;
nliveatts++;
}
pq_sendint(out, nliveatts, 2);
/* fetch bitmap of REPLICATION IDENTITY attributes */
replidentfull = (rel->rd_rel->relreplident == REPLICA_IDENTITY_FULL);
if (!replidentfull)
idattrs = RelationGetIndexAttrBitmap(rel,
INDEX_ATTR_BITMAP_IDENTITY_KEY);
/* send the attributes */
for (i = 0; i < desc->natts; i++)
{
Form_pg_attribute att = TupleDescAttr(desc, i);
uint8 flags = 0;
if (att->attisdropped)
continue;
/* REPLICA IDENTITY FULL means all columns are sent as part of key. */
if (replidentfull ||
bms_is_member(att->attnum - FirstLowInvalidHeapAttributeNumber,
idattrs))
flags |= LOGICALREP_IS_REPLICA_IDENTITY;
pq_sendbyte(out, flags);
/* attribute name */
pq_sendstring(out, NameStr(att->attname));
/* attribute type id */
pq_sendint(out, (int) att->atttypid, sizeof(att->atttypid));
/* attribute mode */
pq_sendint(out, att->atttypmod, sizeof(att->atttypmod));
}
bms_free(idattrs);
}
/*
* Open the local relation associated with the remote one.
*
* Optionally rebuilds the Relcache mapping if it was invalidated
* by local DDL.
*/
LogicalRepRelMapEntry *
logicalrep_rel_open(LogicalRepRelId remoteid, LOCKMODE lockmode)
{
LogicalRepRelMapEntry *entry;
bool found;
if (LogicalRepRelMap == NULL)
logicalrep_relmap_init();
/* Search for existing entry. */
entry = hash_search(LogicalRepRelMap, (void *) &remoteid,
HASH_FIND, &found);
if (!found)
elog(ERROR, "no relation map entry for remote relation ID %u",
remoteid);
/* Need to update the local cache? */
if (!OidIsValid(entry->localreloid))
{
Oid relid;
int i;
int found;
Bitmapset *idkey;
TupleDesc desc;
LogicalRepRelation *remoterel;
MemoryContext oldctx;
remoterel = &entry->remoterel;
/* Try to find and lock the relation by name. */
relid = RangeVarGetRelid(makeRangeVar(remoterel->nspname,
remoterel->relname, -1),
lockmode, true);
if (!OidIsValid(relid))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("logical replication target relation \"%s.%s\" does not exist",
remoterel->nspname, remoterel->relname)));
entry->localrel = heap_open(relid, NoLock);
/*
* We currently only support writing to regular and partitioned
* tables.
*/
if (entry->localrel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("logical replication target relation \"%s.%s\" is not a table",
remoterel->nspname, remoterel->relname)));
/*
* Build the mapping of local attribute numbers to remote attribute
* numbers and validate that we don't miss any replicated columns
* as that would result in potentially unwanted data loss.
*/
desc = RelationGetDescr(entry->localrel);
oldctx = MemoryContextSwitchTo(LogicalRepRelMapContext);
entry->attrmap = palloc(desc->natts * sizeof(int));
MemoryContextSwitchTo(oldctx);
found = 0;
for (i = 0; i < desc->natts; i++)
{
int attnum = logicalrep_rel_att_by_name(remoterel,
NameStr(desc->attrs[i]->attname));
entry->attrmap[i] = attnum;
if (attnum >= 0)
found++;
}
/* TODO, detail message with names of missing columns */
if (found < remoterel->natts)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("logical replication target relation \"%s.%s\" is missing "
"some replicated columns",
remoterel->nspname, remoterel->relname)));
/*
* Check that replica identity matches. We allow for stricter replica
* identity (fewer columns) on subscriber as that will not stop us
* from finding unique tuple. IE, if publisher has identity
* (id,timestamp) and subscriber just (id) this will not be a problem,
* but in the opposite scenario it will.
*
* Don't throw any error here just mark the relation entry as not
* updatable, as replica identity is only for updates and deletes
* but inserts can be replicated even without it.
*/
entry->updatable = true;
idkey = RelationGetIndexAttrBitmap(entry->localrel,
INDEX_ATTR_BITMAP_IDENTITY_KEY);
/* fallback to PK if no replica identity */
if (idkey == NULL)
{
idkey = RelationGetIndexAttrBitmap(entry->localrel,
INDEX_ATTR_BITMAP_PRIMARY_KEY);
/*
* If no replica identity index and no PK, the published table
* must have replica identity FULL.
*/
if (idkey == NULL && remoterel->replident != REPLICA_IDENTITY_FULL)
entry->updatable = false;
}
i = -1;
while ((i = bms_next_member(idkey, i)) >= 0)
{
int attnum = i + FirstLowInvalidHeapAttributeNumber;
if (!AttrNumberIsForUserDefinedAttr(attnum))
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("logical replication target relation \"%s.%s\" uses "
"system columns in REPLICA IDENTITY index",
remoterel->nspname, remoterel->relname)));
attnum = AttrNumberGetAttrOffset(attnum);
if (!bms_is_member(entry->attrmap[attnum], remoterel->attkeys))
{
entry->updatable = false;
break;
}
}
entry->localreloid = relid;
}
else
entry->localrel = heap_open(entry->localreloid, lockmode);
return entry;
}
