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| author | Amit Kapila <akapila@postgresql.org> | 2020-07-20 08:48:26 +0530 |
|---|---|---|
| committer | Amit Kapila <akapila@postgresql.org> | 2020-07-20 08:48:26 +0530 |
| commit | 0bead9af484c1d0a67e690fda47011addaa5bc9d (patch) | |
| tree | 246db2163552a439ac1b7903fd36cb02e73cea3c /src/backend/access/transam/xloginsert.c | |
| parent | d05b172a760e0ccb3008a2144f96053720000b12 (diff) | |
| download | postgresql-0bead9af484c1d0a67e690fda47011addaa5bc9d.tar.gz postgresql-0bead9af484c1d0a67e690fda47011addaa5bc9d.zip | |
Immediately WAL-log subtransaction and top-level XID association.
The logical decoding infrastructure needs to know which top-level
transaction the subxact belongs to, in order to decode all the
changes. Until now that might be delayed until commit, due to the
caching (GPROC_MAX_CACHED_SUBXIDS), preventing features requiring
incremental decoding.
So we also write the assignment info into WAL immediately, as part
of the next WAL record (to minimize overhead) only when wal_level=logical.
We can not remove the existing XLOG_XACT_ASSIGNMENT WAL as that is
required for avoiding overflow in the hot standby snapshot.
Bump XLOG_PAGE_MAGIC, since this introduces XLR_BLOCK_ID_TOPLEVEL_XID.
Author: Tomas Vondra, Dilip Kumar, Amit Kapila
Reviewed-by: Amit Kapila
Tested-by: Neha Sharma and Mahendra Singh Thalor
Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
Diffstat (limited to 'src/backend/access/transam/xloginsert.c')
| -rw-r--r-- | src/backend/access/transam/xloginsert.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c index b21679f09eb..c526bb19281 100644 --- a/src/backend/access/transam/xloginsert.c +++ b/src/backend/access/transam/xloginsert.c @@ -89,11 +89,13 @@ static XLogRecData hdr_rdt; static char *hdr_scratch = NULL; #define SizeOfXlogOrigin (sizeof(RepOriginId) + sizeof(char)) +#define SizeOfXLogTransactionId (sizeof(TransactionId) + sizeof(char)) #define HEADER_SCRATCH_SIZE \ (SizeOfXLogRecord + \ MaxSizeOfXLogRecordBlockHeader * (XLR_MAX_BLOCK_ID + 1) + \ - SizeOfXLogRecordDataHeaderLong + SizeOfXlogOrigin) + SizeOfXLogRecordDataHeaderLong + SizeOfXlogOrigin + \ + SizeOfXLogTransactionId) /* * An array of XLogRecData structs, to hold registered data. @@ -195,6 +197,10 @@ XLogResetInsertion(void) { int i; + /* reset the subxact assignment flag (if needed) */ + if (curinsert_flags & XLOG_INCLUDE_XID) + MarkSubTransactionAssigned(); + for (i = 0; i < max_registered_block_id; i++) registered_buffers[i].in_use = false; @@ -398,7 +404,7 @@ void XLogSetRecordFlags(uint8 flags) { Assert(begininsert_called); - curinsert_flags = flags; + curinsert_flags |= flags; } /* @@ -748,6 +754,19 @@ XLogRecordAssemble(RmgrId rmid, uint8 info, scratch += sizeof(replorigin_session_origin); } + /* followed by toplevel XID, if not already included in previous record */ + if (IsSubTransactionAssignmentPending()) + { + TransactionId xid = GetTopTransactionIdIfAny(); + + /* update the flag (later used by XLogResetInsertion) */ + XLogSetRecordFlags(XLOG_INCLUDE_XID); + + *(scratch++) = (char) XLR_BLOCK_ID_TOPLEVEL_XID; + memcpy(scratch, &xid, sizeof(TransactionId)); + scratch += sizeof(TransactionId); + } + /* followed by main data, if any */ if (mainrdata_len > 0) { |