diff options
Diffstat (limited to 'src/backend/access/gist/gistutil.c')
| -rw-r--r-- | src/backend/access/gist/gistutil.c | 31 |
1 files changed, 26 insertions, 5 deletions
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c index dd975b164c..765329bbcd 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 { /* |