diff options
Diffstat (limited to 'src/backend/access/gist')
| -rw-r--r-- | src/backend/access/gist/gistutil.c | 31 | ||||
| -rw-r--r-- | src/backend/access/gist/gistxlog.c | 21 |
2 files changed, 47 insertions, 5 deletions
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c index dd975b164c5..765329bbcd4 100644 --- a/src/backend/access/gist/gistutil.c +++ b/src/backend/access/gist/gistutil.c @@ -1004,23 +1004,44 @@ gistproperty(Oid index_oid, int attno, } /* - * Temporary and unlogged GiST indexes are not WAL-logged, but we need LSNs - * to detect concurrent page splits anyway. This function provides a fake - * sequence of LSNs for that purpose. + * Some indexes are not WAL-logged, but we need LSNs to detect concurrent page + * splits anyway. This function provides a fake sequence of LSNs for that + * purpose. */ XLogRecPtr gistGetFakeLSN(Relation rel) { - static XLogRecPtr counter = FirstNormalUnloggedLSN; - if (rel->rd_rel->relpersistence == RELPERSISTENCE_TEMP) { /* * Temporary relations are only accessible in our session, so a simple * backend-local counter will do. */ + static XLogRecPtr counter = FirstNormalUnloggedLSN; + return counter++; } + else if (rel->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT) + { + /* + * WAL-logging on this relation will start after commit, so its LSNs + * must be distinct numbers smaller than the LSN at the next commit. + * Emit a dummy WAL record if insert-LSN hasn't advanced after the + * last call. + */ + static XLogRecPtr lastlsn = InvalidXLogRecPtr; + XLogRecPtr currlsn = GetXLogInsertRecPtr(); + + /* Shouldn't be called for WAL-logging relations */ + Assert(!RelationNeedsWAL(rel)); + + /* No need for an actual record if we already have a distinct LSN */ + if (!XLogRecPtrIsInvalid(lastlsn) && lastlsn == currlsn) + currlsn = gistXLogAssignLSN(); + + lastlsn = currlsn; + return currlsn; + } else { /* diff --git a/src/backend/access/gist/gistxlog.c b/src/backend/access/gist/gistxlog.c index d3f3a7b803f..b60dba052fa 100644 --- a/src/backend/access/gist/gistxlog.c +++ b/src/backend/access/gist/gistxlog.c @@ -449,6 +449,9 @@ gist_redo(XLogReaderState *record) case XLOG_GIST_PAGE_DELETE: gistRedoPageDelete(record); break; + case XLOG_GIST_ASSIGN_LSN: + /* nop. See gistGetFakeLSN(). */ + break; default: elog(PANIC, "gist_redo: unknown op code %u", info); } @@ -593,6 +596,24 @@ gistXLogPageDelete(Buffer buffer, FullTransactionId xid, } /* + * Write an empty XLOG record to assign a distinct LSN. + */ +XLogRecPtr +gistXLogAssignLSN(void) +{ + int dummy = 0; + + /* + * Records other than SWITCH_WAL must have content. We use an integer 0 to + * follow the restriction. + */ + XLogBeginInsert(); + XLogSetRecordFlags(XLOG_MARK_UNIMPORTANT); + XLogRegisterData((char *) &dummy, sizeof(dummy)); + return XLogInsert(RM_GIST_ID, XLOG_GIST_ASSIGN_LSN); +} + +/* * Write XLOG record about reuse of a deleted page. */ void |