Merge pull request #8678 from taosdata/fix/TD-10998

[TD-10998]<fix>: set default JSON string type to nchar

packaging/cfg/taos.cfg

@@ -299,8 +299,8 @@ keepColumnName            1
 # percent of redundant data in tsdb meta will compact meta data,0 means donot compact
 # tsdbMetaCompactRatio    0
 
-# default string type used for storing JSON String, options can be binary/nchar, default is binary
-# defaultJSONStrType      binary
+# default string type used for storing JSON String, options can be binary/nchar, default is nchar
+# defaultJSONStrType      nchar
 
 # force TCP transmission 
 # rpcForceTcp        0

src/common/src/tglobal.c

@@ -289,7 +289,7 @@ char     Compressor[32] = "ZSTD_COMPRESSOR";  // ZSTD_COMPRESSOR or GZIP_COMPRES
 int8_t tsDeadLockKillQuery = 0;
 
 // default JSON string type
-char tsDefaultJSONStrType[7] = "binary";
+char tsDefaultJSONStrType[7] = "nchar";
 char tsSmlChildTableName[TSDB_TABLE_NAME_LEN] = ""; //user defined child table name can be specified in tag value. If set to empty system will generate table name using MD5 hash.
 
 int32_t (*monStartSystemFp)() = NULL;