Change the way we handle connection warnings.

Originally we just checked the various SQLCA fields
for any 'W' flag set to determine the database features
during ifxCreateConnectionXact() and ifxSetConnection().

Now check if any SQLCA warning is set first (SQLCA_WARN_SET),
and do the check for any feature warnings only if true. I'm not sure
the former behavior was even correct, since it is not obvious
when SQLCA warning fields get cleared overall.

This commit also adds an is_obsolete field to IfxConnectionInfo
connection structure, to remember wether ifxCreateConnectionXact()
or ifxSetConnection() got a connection to an obsolete Informix
instance version.

I'm planning to use this information later, when attacking the bug
reported in #19, where IMPORT FOREIGN SCHEMA isn't able to import
the table schemas from Informix SE instances, since they don't support
extended data types (e.g. sqlxtdtypes).

ifx_connection.ec

@@ -84,14 +84,36 @@ void ifxCreateConnectionXact(IfxConnectionInfo *coninfo)
 	EXEC SQL CONNECT TO :ifxdsn AS :ifxconname
 		USER :ifxuser USING :ifxpass WITH CONCURRENT TRANSACTION;
 
-	if (ifxGetSQLCAWarn(SQLCA_WARN_TRANSACTIONS) == 'W')
-	{
-		/* save state into connection info */
-		coninfo->tx_enabled = 1;
-	}
+	if (ifxGetSQLCAWarn(SQLCA_WARN_SET) == 'W') {
+
+		if (ifxGetSQLCAWarn(SQLCA_WARN_TRANSACTIONS) == 'W')
+		{
+			/* save state into connection info */
+			coninfo->tx_enabled = 1;
+		}
+
+		if (ifxGetSQLCAWarn(SQLCA_WARN_ANSI) == 'W') {
+			/* ANSI compliant database */
+			coninfo->db_ansi = 1;
+		}
 
-	if (ifxGetSQLCAWarn(SQLCA_WARN_ANSI) == 'W')
-		coninfo->db_ansi = 1;
+		if (ifxGetSQLCAWarn(SQLCA_WARN_NO_IFX_SE) == 'W') {
+			/* connected to an non-SE instance */
+			coninfo->is_obsolete = 0;
+		} else {
+
+			/* SQLCA_WARN_NO_IFX_SE is not set, assume SE instance */
+			coninfo->is_obsolete = 1;
+		}
+
+	} else {
+
+		/*
+		 * If no warning was set, we implicitely assume an Informix SE
+		 * instance
+		 */
+		coninfo->is_obsolete = 1;
+	}
 }
 
 int ifxStartTransaction(IfxPGCachedConnection *cached, IfxConnectionInfo *coninfo)
@@ -477,6 +499,7 @@ int ifxSetConnectionIdent(char *conname)
 
 void ifxSetConnection(IfxConnectionInfo *coninfo)
 {
+
 	EXEC SQL BEGIN DECLARE SECTION;
 	char *ifxconname;
 	EXEC SQL END DECLARE SECTION;
@@ -489,14 +512,37 @@ void ifxSetConnection(IfxConnectionInfo *coninfo)
 	ifxconname = coninfo->conname;
 	EXEC SQL SET CONNECTION :ifxconname;
 
-	if (ifxGetSQLCAWarn(SQLCA_WARN_TRANSACTIONS) == 'W')
-	{
-		/* save state into connection info */
-		coninfo->tx_enabled = 1;
+	if (ifxGetSQLCAWarn(SQLCA_WARN_SET) == 'W') {
+
+		if (ifxGetSQLCAWarn(SQLCA_WARN_TRANSACTIONS) == 'W')
+		{
+			/* save state into connection info */
+			coninfo->tx_enabled = 1;
+		}
+
+		if (ifxGetSQLCAWarn(SQLCA_WARN_ANSI) == 'W') {
+			/* ANSI compliant database */
+			coninfo->db_ansi = 1;
+		}
+
+		if (ifxGetSQLCAWarn(SQLCA_WARN_NO_IFX_SE) == 'W') {
+			/* if 'W' was set, an non-SE instance was detected */
+			coninfo->is_obsolete = 0;
+		} else {
+
+			/* SQLCA_WARN_NO_IFX_SE is not set, assume SE instance */
+			coninfo->is_obsolete = 1;
+		}
+
+	} else {
+
+		/*
+		 * If no warning was set, we implicitely assume an Informix SE
+		 * instance
+		 */
+		coninfo->is_obsolete = 1;
 	}
 
-	if (ifxGetSQLCAWarn(SQLCA_WARN_ANSI) == 'W')
-		coninfo->db_ansi = 1;
 }
 
 void ifxPrepareQuery(char *query, char *stmt_name)

ifx_fdw.c

@@ -2523,16 +2523,17 @@ static IfxCachedConnection * ifxSetupConnection(IfxConnectionInfo **coninfo,
 	/*
 	 * Give a warning if we have mismatching DBLOCALE settings.
 	 */
-	if (ifxGetSQLCAWarn(SQLCA_WARN_DB_LOCALE_MISMATCH) == 'W')
+	if ((ifxGetSQLCAWarn(SQLCA_WARN_SET) == 'W')
+		&& (ifxGetSQLCAWarn(SQLCA_WARN_DB_LOCALE_MISMATCH) == 'W'))
 		elog(WARNING, "mismatching DBLOCALE \"%s\"",
 			 (*coninfo)->db_locale);
 
 	/*
 	 * Give a NOTICE in case this is an INFORMIX SE
 	 * database instance.
 	 */
-	if (ifxGetSQLCAWarn(SQLCA_WARN_NO_IFX_SE) == 'W')
-		elog(NOTICE, "connected to an non-Informix SE instance");
+	if ((*coninfo)->is_obsolete == 1)
+		elog(NOTICE, "connected to a Informix SE instance");
 
 	return cached_handle;
 }
@@ -5214,6 +5215,11 @@ static void ifxConnInfoSetDefaults(IfxConnectionInfo *coninfo)
 	coninfo->username      = "\0";
 	coninfo->password      = "\0";
 
+	/*
+	 * per default assume non-SE informix instance.
+	 */
+	coninfo->is_obsolete = 0;
+
 	/* default scan mode */
 	coninfo->scan_mode     = IFX_PLAN_SCAN;
 }

ifx_type_compat.h

@@ -265,6 +265,7 @@ typedef enum IfxExtendedType
 	IFX_XTD_DBSENDRECV    = 21,
 	IFX_XTD_SRVSENDRECV   = 22,
 	IFX_XTD_FUNCARG       = 23
+
 } IfxExtendedType;
 
 /*
@@ -439,6 +440,7 @@ typedef struct IfxConnectionInfo
 	short tx_enabled; /* 0 = n tx, 1 = tx enabled */
 	int   xact_level; /* current nest level of transactions */
 	short db_ansi; /* 0 = non-ANSI database, 1 = ANSI-enabled database */
+	short is_obsolete; /* currently: 0 = non SE instance, 1 = Informix SE instance */
 	short predicate_pushdown; /* 0 = disabled, 1 = enabled */
 	short enable_blobs; /* 0 = no special BLOB support,
 						   1 = special BLOB support */