diff options
Diffstat (limited to 'src/backend/optimizer/path/tidpath.c')
-rw-r--r-- | src/backend/optimizer/path/tidpath.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/src/backend/optimizer/path/tidpath.c b/src/backend/optimizer/path/tidpath.c index 2470493708a..84564dde734 100644 --- a/src/backend/optimizer/path/tidpath.c +++ b/src/backend/optimizer/path/tidpath.c @@ -12,6 +12,12 @@ * this allows * WHERE ctid IN (tid1, tid2, ...) * + * We also support "WHERE CURRENT OF cursor" conditions (CurrentOfExpr), + * which amount to "CTID = run-time-determined-TID". These could in + * theory be translated to a simple comparison of CTID to the result of + * a function, but in practice it works better to keep the special node + * representation all the way through to execution. + * * There is currently no special support for joins involving CTID; in * particular nothing corresponding to best_inner_indexscan(). Since it's * not very useful to store TIDs of one table in another table, there @@ -24,7 +30,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/tidpath.c,v 1.29 2007/01/05 22:19:31 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/tidpath.c,v 1.30 2007/06/11 01:16:22 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -174,6 +180,12 @@ TidQualFromExpr(Node *expr, int varno) if (IsTidEqualAnyClause((ScalarArrayOpExpr *) expr, varno)) rlst = list_make1(expr); } + else if (expr && IsA(expr, CurrentOfExpr)) + { + /* another base case: check for CURRENT OF on this rel */ + if (((CurrentOfExpr *) expr)->cvarno == varno) + rlst = list_make1(expr); + } else if (and_clause(expr)) { foreach(l, ((BoolExpr *) expr)->args) |