From c52672ff1de4d7c55c4b50eb7986f45801ea4c60 Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Mon, 16 Mar 2020 13:27:51 +0100 Subject: [PATCH] Prepare to support non-tables in publications This by itself doesn't change any functionality but prepares the way for having relations other than base tables in publications. Make arrangements for COPY handling the initial table sync. For non-tables we have to use COPY (SELECT ...) instead of directly copying from the table, but then we have to take care to omit generated columns from the column list. Also, remove a hardcoded reference to relkind = 'r' and rely on pg_relation_is_publishable(), which matches what the publisher can actually publish and is correct even in cross-version scenarios. Discussion: https://www.postgresql.org/message-id/flat/CA+HiwqH=Y85vRK3mOdjEkqFK+E=ST=eQiHdpj43L=_eJMOOznQ@mail.gmail.com --- src/backend/replication/logical/tablesync.c | 43 ++++++++++++++++----- src/include/replication/logicalproto.h | 1 + 2 files changed, 35 insertions(+), 9 deletions(-) diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c index 98825f01e9..358b0a3726 100644 --- a/src/backend/replication/logical/tablesync.c +++ b/src/backend/replication/logical/tablesync.c @@ -639,26 +639,27 @@ fetch_remote_table_info(char *nspname, char *relname, WalRcvExecResult *res; StringInfoData cmd; TupleTableSlot *slot; - Oid tableRow[2] = {OIDOID, CHAROID}; - Oid attrRow[4] = {TEXTOID, OIDOID, INT4OID, BOOLOID}; + Oid tableRow[] = {OIDOID, CHAROID, CHAROID, BOOLOID}; + Oid attrRow[] = {TEXTOID, OIDOID, INT4OID, BOOLOID}; bool isnull; int natt; + bool remote_is_publishable; lrel->nspname = nspname; lrel->relname = relname; /* First fetch Oid and replica identity. */ initStringInfo(&cmd); - appendStringInfo(&cmd, "SELECT c.oid, c.relreplident" + appendStringInfo(&cmd, "SELECT c.oid, c.relreplident, c.relkind," + " pg_relation_is_publishable(c.oid)" " FROM pg_catalog.pg_class c" " INNER JOIN pg_catalog.pg_namespace n" " ON (c.relnamespace = n.oid)" " WHERE n.nspname = %s" - " AND c.relname = %s" - " AND c.relkind = 'r'", + " AND c.relname = %s", quote_literal_cstr(nspname), quote_literal_cstr(relname)); - res = walrcv_exec(wrconn, cmd.data, 2, tableRow); + res = walrcv_exec(wrconn, cmd.data, lengthof(tableRow), tableRow); if (res->status != WALRCV_OK_TUPLES) ereport(ERROR, @@ -675,6 +676,13 @@ fetch_remote_table_info(char *nspname, char *relname, Assert(!isnull); lrel->replident = DatumGetChar(slot_getattr(slot, 2, &isnull)); Assert(!isnull); + lrel->relkind = DatumGetChar(slot_getattr(slot, 3, &isnull)); + Assert(!isnull); + remote_is_publishable = DatumGetBool(slot_getattr(slot, 4, &isnull)); + if (isnull || !remote_is_publishable) + ereport(ERROR, + (errmsg("table \"%s.%s\" on the publisher is not publishable", + nspname, relname))); ExecDropSingleTupleTableSlot(slot); walrcv_clear_result(res); @@ -696,7 +704,7 @@ fetch_remote_table_info(char *nspname, char *relname, lrel->remoteid, (walrcv_server_version(wrconn) >= 120000 ? "AND a.attgenerated = ''" : ""), lrel->remoteid); - res = walrcv_exec(wrconn, cmd.data, 4, attrRow); + res = walrcv_exec(wrconn, cmd.data, lengthof(attrRow), attrRow); if (res->status != WALRCV_OK_TUPLES) ereport(ERROR, @@ -765,8 +773,25 @@ copy_table(Relation rel) /* Start copy on the publisher. */ initStringInfo(&cmd); - appendStringInfo(&cmd, "COPY %s TO STDOUT", - quote_qualified_identifier(lrel.nspname, lrel.relname)); + if (lrel.relkind == RELKIND_RELATION) + appendStringInfo(&cmd, "COPY %s TO STDOUT", + quote_qualified_identifier(lrel.nspname, lrel.relname)); + else + { + /* + * For non-tables, we need to do COPY (SELECT ...), but we can't just + * do SELECT * because we need to not copy generated columns. + */ + appendStringInfo(&cmd, "COPY (SELECT "); + for (int i = 0; i < lrel.natts; i++) + { + appendStringInfoString(&cmd, quote_identifier(lrel.attnames[i])); + if (i < lrel.natts - 1) + appendStringInfoString(&cmd, ", "); + } + appendStringInfo(&cmd, " FROM %s) TO STDOUT", + quote_qualified_identifier(lrel.nspname, lrel.relname)); + } res = walrcv_exec(wrconn, cmd.data, 0, NULL); pfree(cmd.data); if (res->status != WALRCV_OK_COPY_OUT) diff --git a/src/include/replication/logicalproto.h b/src/include/replication/logicalproto.h index 2cc2dc4db3..4860561be9 100644 --- a/src/include/replication/logicalproto.h +++ b/src/include/replication/logicalproto.h @@ -49,6 +49,7 @@ typedef struct LogicalRepRelation char **attnames; /* column names */ Oid *atttyps; /* column types */ char replident; /* replica identity */ + char relkind; /* remote relation kind */ Bitmapset *attkeys; /* Bitmap of key columns */ } LogicalRepRelation; -- 2.25.0