Re: [PATCH 07/16] Log enough data into the wal to reconstruct logical changes from it if wal_level=logical

On 13.06.2012 14:28, Andres Freund wrote:
> @@ -2584,6 +2610,73 @@ l1:
> rdata[1].buffer_std = true;
> rdata[1].next = NULL;
>
> + /*
> + * XXX: We could decide not to log changes when the origin is not the
> + * local node, that should reduce redundant logging.
> + */
> + if(need_tuple){
> + xl_heap_header xlhdr;
> ...
> + relationFindPrimaryKey(relation,&indexoid,&pknratts, pkattnum, pktypoid, pkopclass);
> +
> + if(!indexoid){
> + elog(WARNING, "Could not find primary key for table with oid %u",
> + relation->rd_id);
> + goto no_index_found;
> + }
> +
> + index_rel = index_open(indexoid, AccessShareLock);
> +
> + indexdesc = RelationGetDescr(index_rel);
> +
> + for(natt = 0; natt< indexdesc->natts; natt++){
> + idxvals[natt] =
> + fastgetattr(&tp, pkattnum[natt], desc,&idxisnull[natt]);
> + Assert(!idxisnull[natt]);
> + }
> +
> + idxtuple = heap_form_tuple(indexdesc, idxvals, idxisnull);
> +
> + xlhdr.t_infomask2 = idxtuple->t_data->t_infomask2;
> + xlhdr.t_infomask = idxtuple->t_data->t_infomask;
> + xlhdr.t_hoff = idxtuple->t_data->t_hoff;
> +
> + rdata[1].next =&(rdata[2]);
> + rdata[2].data = (char*)&xlhdr;
> + rdata[2].len = SizeOfHeapHeader;
> + rdata[2].buffer = InvalidBuffer;
> + rdata[2].next = NULL;
> +
> + rdata[2].next =&(rdata[3]);
> + rdata[3].data = (char *) idxtuple->t_data + offsetof(HeapTupleHeaderData, t_bits);
> + rdata[3].len = idxtuple->t_len - offsetof(HeapTupleHeaderData, t_bits);
> + rdata[3].buffer = InvalidBuffer;
> + rdata[3].next = NULL;
> +
> + heap_close(index_rel, NoLock);
> + no_index_found:
> + ;
> + }
> +
> recptr = XLogInsert(RM_HEAP_ID, XLOG_HEAP_DELETE, rdata);
>
> PageSetLSN(page, recptr);

It's not cool to do all that primary key lookup stuff within the
critical section, while holding a lock on the page.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com