README.md in embulk-output-db2-0.8.2 vs README.md in embulk-output-db2-0.8.3

@@ -18,11 +18,12 @@
 - **database**: destination database name (string, required)
 - **schema**: destination schema name (string, default: use the default schema)
 - **table**: destination table name (string, required)
 - **create_table_constraint**: table constraint added to `CREATE TABLE` statement, like `CREATE TABLE <table_name> (<column1> <type1>, <column2> <type2>, ..., <create_table_constraint>) <create_table_option>`.
 - **create_table_option**: table option added to `CREATE TABLE` statement, like `CREATE TABLE <table_name> (<column1> <type1>, <column2> <type2>, ..., <create_table_constraint>) <create_table_option>`.
+- **transaction_isolation**: transaction isolation level for each connection ("read_uncommitted", "read_committed", "repeatable_read" or "serializable"). if not specified, database default value will be used.
 - **options**: extra connection properties (hash, default: {})
-- **retry_limit**: max retry count for database operations (integer, default: 12)
+- **retry_limit**: max retry count for database operations (integer, default: 12). When intermediate table to create already created by another process, this plugin will retry with another table name to avoid collision.
 - **retry_wait**: initial retry wait time in milliseconds (integer, default: 1000 (1 second))
 - **max_retry_wait**: upper limit of retry wait, which will be doubled at every retry (integer, default: 1800000 (30 minutes))
 - **mode**: "insert", "insert_direct", "truncate_insert" or "replace". See below. (string, required)
 - **insert_method**: see below
 - **batch_size**: size of a single batch insert (integer, default: 16777216)