database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-07 00:36:50 +03:00
Code Activity

Generic Messages for Logical Decoding

Browse Source 
API and mechanism to allow generic messages to be inserted into WAL that are
intended to be read by logical decoding plugins. This commit adds an optional
new callback to the logical decoding API.

Messages are either text or bytea. Messages can be transactional, or not, and
are identified by a prefix to allow multiple concurrent decoding plugins.

(Not to be confused with Generic WAL records, which are intended to allow crash
recovery of extensible objects.)

Author: Petr Jelinek and Andres Freund
Reviewers: Artur Zakirov, Tomas Vondra, Simon Riggs
Discussion: 5685F999.6010202@2ndquadrant.com
This commit is contained in:
Simon Riggs
2016-04-06 10:05:41 +01:00
parent 989be0810d
commit 3fe3511d05
27 changed files with 693 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
src/backend/replication/logical/decode.c
View File

@ -39,6 +39,7 @@
#include "replication/decode.h"
#include "replication/logical.h"
#include "replication/message.h"
#include "replication/reorderbuffer.h"
#include "replication/origin.h"
#include "replication/snapbuild.h"
@ -58,6 +59,7 @@ static void DecodeHeapOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf);
static void DecodeHeap2Op(LogicalDecodingContext *ctx, XLogRecordBuffer *buf);
static void DecodeXactOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf);
static void DecodeStandbyOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf);
static void DecodeLogicalMsgOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf);
/* individual record(group)'s handlers */
static void DecodeInsert(LogicalDecodingContext *ctx, XLogRecordBuffer *buf);
@ -123,6 +125,10 @@ LogicalDecodingProcessRecord(LogicalDecodingContext *ctx, XLogReaderState *recor
DecodeHeapOp(ctx, &buf);
break;
case RM_LOGICALMSG_ID:
DecodeLogicalMsgOp(ctx, &buf);
break;
/*
* Rmgrs irrelevant for logical decoding; they describe stuff not
* represented in logical decoding. Add new rmgrs in rmgrlist.h's
@ -458,6 +464,46 @@ DecodeHeapOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
}
}
/*
* Handle rmgr LOGICALMSG_ID records for DecodeRecordIntoReorderBuffer().
*/
static void
DecodeLogicalMsgOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
{
SnapBuild *builder = ctx->snapshot_builder;
XLogReaderState *r = buf->record;
TransactionId xid = XLogRecGetXid(r);
uint8 info = XLogRecGetInfo(r) & ~XLR_INFO_MASK;
Snapshot snapshot;
xl_logical_message *message;
if (info != XLOG_LOGICAL_MESSAGE)
elog(ERROR, "unexpected RM_LOGICALMSG_ID record type: %u", info);
ReorderBufferProcessXid(ctx->reorder, XLogRecGetXid(r), buf->origptr);
/* No point in doing anything yet. */
if (SnapBuildCurrentState(builder) < SNAPBUILD_FULL_SNAPSHOT)
return;
message = (xl_logical_message *) XLogRecGetData(r);
if (message->transactional &&
!SnapBuildProcessChange(builder, xid, buf->origptr))
return;
else if (!message->transactional &&
(SnapBuildCurrentState(builder) != SNAPBUILD_CONSISTENT ||
SnapBuildXactNeedsSkip(builder, buf->origptr)))
return;
snapshot = SnapBuildGetOrBuildSnapshot(builder, xid);
ReorderBufferQueueMessage(ctx->reorder, xid, snapshot, buf->endptr,
message->transactional,
message->message, /* first part of message is prefix */
message->message_size,
message->message + message->prefix_size);
}
static inline bool
FilterByOrigin(LogicalDecodingContext *ctx, RepOriginId origin_id)
{