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Handle heap rewrites even better in logical decoding

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Logical decoding should not publish anything about tables created as
part of a heap rewrite during DDL.  Those tables don't exist externally,
so consumers of logical decoding cannot do anything sensible with that
information.  In ab28feae2b, we worked
around this for built-in logical replication, but that was hack.

This is a more proper fix: We mark such transient heaps using the new
field pg_class.relwrite, linking to the original relation OID.  By
default, we ignore them in logical decoding before they get to the
output plugin.  Optionally, a plugin can register their interest in
getting such changes, if they handle DDL specially, in which case the
new field will help them get information about the actual table.

Reviewed-by: Craig Ringer <craig@2ndquadrant.com>
This commit is contained in:
Peter Eisentraut
2018-03-21 09:13:24 -04:00
parent be8a7a6866
commit 325f2ec555
20 changed files with 113 additions and 103 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
src/backend/replication/logical/logical.c
View File

@@ -317,6 +317,8 @@ CreateInitDecodingContext(char *plugin,
startup_cb_wrapper(ctx, &ctx->options, true);
MemoryContextSwitchTo(old_context);
ctx->reorder->output_rewrites = ctx->options.receive_rewrites;
return ctx;
}
@@ -410,6 +412,8 @@ CreateDecodingContext(XLogRecPtr start_lsn,
startup_cb_wrapper(ctx, &ctx->options, false);
MemoryContextSwitchTo(old_context);
ctx->reorder->output_rewrites = ctx->options.receive_rewrites;
ereport(LOG,
(errmsg("starting logical decoding for slot \"%s\"",
NameStr(slot->data.name)),

7
src/backend/replication/logical/reorderbuffer.c
View File

@@ -1402,6 +1402,13 @@ ReorderBufferCommit(ReorderBuffer *rb, TransactionId xid,
if (!RelationIsLogicallyLogged(relation))
goto change_done;
/*
* Ignore temporary heaps created during DDL unless the
* plugin has asked for them.
*/
if (relation->rd_rel->relrewrite && !rb->output_rewrites)
goto change_done;
/*
* For now ignore sequence changes entirely. Most of the
* time they don't log changes using records we

26
src/backend/replication/pgoutput/pgoutput.c
View File

@@ -21,7 +21,6 @@
#include "utils/inval.h"
#include "utils/int8.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
#include "utils/varlena.h"
@@ -511,31 +510,6 @@ get_rel_sync_entry(PGOutputData *data, Oid relid)
{
Publication *pub = lfirst(lc);
/*
* Skip tables that look like they are from a heap rewrite (see
* make_new_heap()). We need to skip them because the subscriber
* won't have a table by that name to receive the data. That
* means we won't ship the new data in, say, an added column with
* a DEFAULT, but if the user applies the same DDL manually on the
* subscriber, then this will work out for them.
*
* We only need to consider the alltables case, because such a
* transient heap won't be an explicit member of a publication.
*/
if (pub->alltables)
{
char *relname = get_rel_name(relid);
unsigned int u;
int n;
if (sscanf(relname, "pg_temp_%u%n", &u, &n) == 1 &&
relname[n] == '\0')
{
if (get_rel_relkind(u) == RELKIND_RELATION)
break;
}
}
if (pub->alltables || list_member_oid(pubids, pub->oid))
{
entry->pubactions.pubinsert |= pub->pubactions.pubinsert;