diff options
Diffstat (limited to 'contrib/dblink/dblink.c')
| -rw-r--r-- | contrib/dblink/dblink.c | 105 |
1 files changed, 100 insertions, 5 deletions
diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c index bba0d2adc3c..e8ad94ba841 100644 --- a/contrib/dblink/dblink.c +++ b/contrib/dblink/dblink.c @@ -53,6 +53,7 @@ #include "utils/acl.h" #include "utils/builtins.h" #include "utils/fmgroids.h" +#include "utils/guc.h" #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/rel.h" @@ -86,7 +87,8 @@ typedef struct storeInfo */ static Datum dblink_record_internal(FunctionCallInfo fcinfo, bool is_async); static void prepTuplestoreResult(FunctionCallInfo fcinfo); -static void materializeResult(FunctionCallInfo fcinfo, PGresult *res); +static void materializeResult(FunctionCallInfo fcinfo, PGconn *conn, + PGresult *res); static void materializeQueryResult(FunctionCallInfo fcinfo, PGconn *conn, const char *conname, @@ -118,6 +120,8 @@ static void validate_pkattnums(Relation rel, int **pkattnums, int *pknumatts); static bool is_valid_dblink_option(const PQconninfoOption *options, const char *option, Oid context); +static int applyRemoteGucs(PGconn *conn); +static void restoreLocalGucs(int nestlevel); /* Global */ static remoteConn *pconn = NULL; @@ -605,7 +609,7 @@ dblink_fetch(PG_FUNCTION_ARGS) errmsg("cursor \"%s\" does not exist", curname))); } - materializeResult(fcinfo, res); + materializeResult(fcinfo, conn, res); return (Datum) 0; } @@ -750,7 +754,7 @@ dblink_record_internal(FunctionCallInfo fcinfo, bool is_async) } else { - materializeResult(fcinfo, res); + materializeResult(fcinfo, conn, res); } } } @@ -806,7 +810,7 @@ prepTuplestoreResult(FunctionCallInfo fcinfo) * The PGresult will be released in this function. */ static void -materializeResult(FunctionCallInfo fcinfo, PGresult *res) +materializeResult(FunctionCallInfo fcinfo, PGconn *conn, PGresult *res) { ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; @@ -816,7 +820,7 @@ materializeResult(FunctionCallInfo fcinfo, PGresult *res) PG_TRY(); { TupleDesc tupdesc; - bool is_sql_cmd = false; + bool is_sql_cmd; int ntuples; int nfields; @@ -877,6 +881,7 @@ materializeResult(FunctionCallInfo fcinfo, PGresult *res) if (ntuples > 0) { AttInMetadata *attinmeta; + int nestlevel = -1; Tuplestorestate *tupstore; MemoryContext oldcontext; int row; @@ -884,6 +889,10 @@ materializeResult(FunctionCallInfo fcinfo, PGresult *res) attinmeta = TupleDescGetAttInMetadata(tupdesc); + /* Set GUCs to ensure we read GUC-sensitive data types correctly */ + if (!is_sql_cmd) + nestlevel = applyRemoteGucs(conn); + oldcontext = MemoryContextSwitchTo( rsinfo->econtext->ecxt_per_query_memory); tupstore = tuplestore_begin_heap(true, false, work_mem); @@ -920,6 +929,9 @@ materializeResult(FunctionCallInfo fcinfo, PGresult *res) tuplestore_puttuple(tupstore, tuple); } + /* clean up GUC settings, if we changed any */ + restoreLocalGucs(nestlevel); + /* clean up and return the tuplestore */ tuplestore_donestoring(tupstore); } @@ -1053,6 +1065,7 @@ static PGresult * storeQueryResult(storeInfo *sinfo, PGconn *conn, const char *sql) { bool first = true; + int nestlevel = -1; PGresult *res; if (!PQsendQuery(conn, sql)) @@ -1072,6 +1085,15 @@ storeQueryResult(storeInfo *sinfo, PGconn *conn, const char *sql) if (PQresultStatus(sinfo->cur_res) == PGRES_SINGLE_TUPLE) { /* got one row from possibly-bigger resultset */ + + /* + * Set GUCs to ensure we read GUC-sensitive data types correctly. + * We shouldn't do this until we have a row in hand, to ensure + * libpq has seen any earlier ParameterStatus protocol messages. + */ + if (first && nestlevel < 0) + nestlevel = applyRemoteGucs(conn); + storeRow(sinfo, sinfo->cur_res, first); PQclear(sinfo->cur_res); @@ -1092,6 +1114,9 @@ storeQueryResult(storeInfo *sinfo, PGconn *conn, const char *sql) } } + /* clean up GUC settings, if we changed any */ + restoreLocalGucs(nestlevel); + /* return last_res */ res = sinfo->last_res; sinfo->last_res = NULL; @@ -2898,3 +2923,73 @@ is_valid_dblink_option(const PQconninfoOption *options, const char *option, return true; } + +/* + * Copy the remote session's values of GUCs that affect datatype I/O + * and apply them locally in a new GUC nesting level. Returns the new + * nestlevel (which is needed by restoreLocalGucs to undo the settings), + * or -1 if no new nestlevel was needed. + * + * We use the equivalent of a function SET option to allow the settings to + * persist only until the caller calls restoreLocalGucs. If an error is + * thrown in between, guc.c will take care of undoing the settings. + */ +static int +applyRemoteGucs(PGconn *conn) +{ + static const char *const GUCsAffectingIO[] = { + "DateStyle", + "IntervalStyle" + }; + + int nestlevel = -1; + int i; + + for (i = 0; i < lengthof(GUCsAffectingIO); i++) + { + const char *gucName = GUCsAffectingIO[i]; + const char *remoteVal = PQparameterStatus(conn, gucName); + const char *localVal; + + /* + * If the remote server is pre-8.4, it won't have IntervalStyle, but + * that's okay because its output format won't be ambiguous. So just + * skip the GUC if we don't get a value for it. (We might eventually + * need more complicated logic with remote-version checks here.) + */ + if (remoteVal == NULL) + continue; + + /* + * Avoid GUC-setting overhead if the remote and local GUCs already + * have the same value. + */ + localVal = GetConfigOption(gucName, false, false); + Assert(localVal != NULL); + + if (strcmp(remoteVal, localVal) == 0) + continue; + + /* Create new GUC nest level if we didn't already */ + if (nestlevel < 0) + nestlevel = NewGUCNestLevel(); + + /* Apply the option (this will throw error on failure) */ + (void) set_config_option(gucName, remoteVal, + PGC_USERSET, PGC_S_SESSION, + GUC_ACTION_SAVE, true, 0); + } + + return nestlevel; +} + +/* + * Restore local GUCs after they have been overlaid with remote settings. + */ +static void +restoreLocalGucs(int nestlevel) +{ + /* Do nothing if no new nestlevel was created */ + if (nestlevel > 0) + AtEOXact_GUC(true, nestlevel); +} |