From 75c1921cd6c868c5995b88113b4463a4830b9a27 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Wed, 7 Aug 2019 10:28:16 +0900 Subject: [PATCH] Adjust tuple data lookup logic in multi-insert logical decoding As of now, logical decoding of a multi-insert has been scanning all xl_multi_insert_tuple entries only if XLH_INSERT_CONTAINS_NEW_TUPLE was getting set in the record. This is not an issue on HEAD as multi-insert records are not used for system catalogs, but the logical decoding logic includes all the code necessary to handle that properly, except that the code missed to iterate correctly over all xl_multi_insert_tuple entries when the flag is not set. Hence, when trying to use multi-insert for system catalogs, an assertion would be triggered. An upcoming patch is going to make use of multi-insert for system catalogs, and this fixes the logic to make sure that all entries are scanned correctly without softening the existing assertions. Reported-by: Daniel Gustafsson Author: Michael Paquier Reviewed-by: Daniel Gustafsson Discussion: https://postgr.es/m/CBFFD532-C033-49EB-9A5A-F67EAEE9EB0B@yesql.se --- src/backend/replication/logical/decode.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c index 151c3ef8825..5315d93af06 100644 --- a/src/backend/replication/logical/decode.c +++ b/src/backend/replication/logical/decode.c @@ -900,7 +900,12 @@ DecodeMultiInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf) if (FilterByOrigin(ctx, XLogRecGetOrigin(r))) return; + /* + * As multi_insert is not used for catalogs yet, the block should always + * have data even if a full-page write of it is taken. + */ tupledata = XLogRecGetBlockData(r, 0, &tuplelen); + Assert(tupledata != NULL); data = tupledata; for (i = 0; i < xlrec->ntuples; i++) @@ -916,6 +921,10 @@ DecodeMultiInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf) memcpy(&change->data.tp.relnode, &rnode, sizeof(RelFileNode)); + xlhdr = (xl_multi_insert_tuple *) SHORTALIGN(data); + data = ((char *) xlhdr) + SizeOfMultiInsertTuple; + datalen = xlhdr->datalen; + /* * CONTAINS_NEW_TUPLE will always be set currently as multi_insert * isn't used for catalogs, but better be future proof. @@ -927,10 +936,6 @@ DecodeMultiInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf) { HeapTupleHeader header; - xlhdr = (xl_multi_insert_tuple *) SHORTALIGN(data); - data = ((char *) xlhdr) + SizeOfMultiInsertTuple; - datalen = xlhdr->datalen; - change->data.tp.newtuple = ReorderBufferGetTupleBuf(ctx->reorder, datalen); @@ -953,8 +958,6 @@ DecodeMultiInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf) memcpy((char *) tuple->tuple.t_data + SizeofHeapTupleHeader, (char *) data, datalen); - data += datalen; - header->t_infomask = xlhdr->t_infomask; header->t_infomask2 = xlhdr->t_infomask2; header->t_hoff = xlhdr->t_hoff; @@ -973,6 +976,9 @@ DecodeMultiInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf) ReorderBufferQueueChange(ctx->reorder, XLogRecGetXid(r), buf->origptr, change); + + /* move to the next xl_multi_insert_tuple entry */ + data += datalen; } Assert(data == tupledata + tuplelen); }