diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/tcop/fastpath.c | 60 |
1 files changed, 46 insertions, 14 deletions
diff --git a/src/backend/tcop/fastpath.c b/src/backend/tcop/fastpath.c index fd30bd58ac5..05640b5be8f 100644 --- a/src/backend/tcop/fastpath.c +++ b/src/backend/tcop/fastpath.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/tcop/fastpath.c,v 1.43 2000/07/03 23:09:46 wieck Exp $ + * $Header: /cvsroot/pgsql/src/backend/tcop/fastpath.c,v 1.44 2000/10/24 20:59:35 tgl Exp $ * * NOTES * This cruft is the server side of PQfn. @@ -271,9 +271,14 @@ update_fp_info(Oid func_id, struct fp_info * fip) * Note: All ordinary errors result in elog(ERROR,...). However, * if we lose the frontend connection there is no one to elog to, * and no use in proceeding... + * + * Note: palloc()s done here and in the called function do not need to be + * cleaned up explicitly. We are called from PostgresMain() in the + * QueryContext memory context, which will be automatically reset when + * control returns to PostgresMain. */ int -HandleFunctionRequest() +HandleFunctionRequest(void) { Oid fid; int argsize; @@ -285,6 +290,32 @@ HandleFunctionRequest() char *p; struct fp_info *fip; + /* + * XXX FIXME: This protocol is misdesigned. + * + * We really do not want to elog() before having swallowed all of the + * frontend's fastpath message; otherwise we will lose sync with the input + * datastream. What should happen is we absorb all of the input message + * per protocol syntax, and *then* do error checking (including lookup of + * the given function ID) and elog if appropriate. Unfortunately, because + * we cannot even read the message properly without knowing whether the + * data types are pass-by-ref or pass-by-value, it's not all that easy to + * do :-(. The protocol should require the client to supply what it + * thinks is the typbyval and typlen value for each arg, so that we can + * read the data without having to do any lookups. Then after we've read + * the message, we should do the lookups, verify agreement of the actual + * function arg types with what we received, and finally call the function. + * + * As things stand, not only will we lose sync for an invalid message + * (such as requested function OID doesn't exist), but we may lose sync + * for a perfectly valid message if we are in transaction-aborted state! + * This can happen because our database lookup attempts may fail entirely + * in abort state. + * + * Unfortunately I see no way to fix this without breaking a lot of + * existing clients. Maybe do it as part of next protocol version change. + */ + if (pq_getint(&tmp, 4)) /* function oid */ return EOF; fid = (Oid) tmp; @@ -293,23 +324,13 @@ HandleFunctionRequest() /* * This is where the one-back caching is done. If you want to save - * more state, make this a loop around an array. + * more state, make this a loop around an array. Given the relatively + * short lifespan of the cache, not clear that there's any win possible. */ fip = &last_fp; if (!valid_fp_info(fid, fip)) update_fp_info(fid, fip); - /* - * XXX FIXME: elog() here means we lose sync with the frontend, since - * we have not swallowed all of its input message. What should happen - * is we absorb all of the input message per protocol syntax, and - * *then* do error checking (including lookup of the given function ID) - * and elog if appropriate. Unfortunately, because we cannot even read - * the message properly without knowing whether the data types are - * pass-by-ref or pass-by-value, it's not all that easy to fix :-(. - * This protocol is misdesigned. - */ - if (fip->flinfo.fn_nargs != nargs || nargs > FUNC_MAX_ARGS) { elog(ERROR, "HandleFunctionRequest: actual arguments (%d) != registered arguments (%d)", @@ -366,6 +387,17 @@ HandleFunctionRequest() } } + /* + * Now that we've eaten the input message, check to see if we actually + * want to do the function call or not. + * + * Currently, we report an error if in ABORT state, or return a dummy + * NULL response if fastpath support has been compiled out. + */ + if (IsAbortedTransactionBlockState()) + elog(ERROR, "current transaction is aborted, " + "queries ignored until end of transaction block"); + #ifdef NO_FASTPATH /* force a NULL return */ retval = (Datum) 0; |