Dynamic Join Filter通过动态收集Hash Join的右表Join键信息，在Join计算前过滤左表中无法Join匹配的数据，从而提升AnalyticDB PostgreSQL版的Hash Join的性能。使用TPC-H在本地生成1 GB测试数据，操作方法，请参见生成测试数据。创建用于测试的lineitem和part表，建表语句如下：CREATE TABLE LINEITEM ( L_ORDERKEY BIGINT NOT NULL, L_PARTKEY INTEGER NOT NULL, L_SUPPKEY INTEGER NOT NULL, L_LINENUMBER INTEGER NOT NULL, L_QUANTITY NUMERIC(15,2) NOT NULL, L_EXTENDEDPRICE NUMERIC(15,2) NOT NULL, L_DISCOUNT NUMERIC(15,2) NOT NULL, L_TAX NUMERIC(15,2) NOT NULL, L_RETURNFLAG CHAR(1) NOT NULL, L_LINESTATUS CHAR(1) NOT NULL, L_SHIPDATE DATE NOT NULL, L_COMMITDATE DATE NOT NULL, L_RECEIPTDATE DATE NOT NULL, L_SHIPINSTRUCT CHAR(25) NOT NULL, L_SHIPMODE CHAR(10) NOT NULL, L_COMMENT VARCHAR(44) NOT NULL ) WITH (APPENDONLY=TRUE, ORIENTATION=COLUMN) DISTRIBUTED BY (L_ORDERKEY, L_LINENUMBER); CREATE TABLE PART ( P_PARTKEY INTEGER NOT NULL, P_NAME VARCHAR(55) NOT NULL, P_MFGR CHAR(25) NOT NULL, P_BRAND CHAR(10) NOT NULL, P_TYPE VARCHAR(25) NOT NULL, P_SIZE INTEGER NOT NULL, P_CONTAINER CHAR(10) NOT NULL, P_RETAILPRICE NUMERIC(15,2) NOT NULL, P_COMMENT VARCHAR(23) NOT NULL ) WITH (APPENDONLY=TRUE, ORIENTATION=COLUMN) DISTRIBUTED BY (P_PARTKEY);使用\COPY命令导入1 GB测试数据，语句如下：\COPY LINEITEM FROM 'lineitem.tbl' with DELIMITER '|' NULL ''; \COPY PART FROM 'part.tbl' with DELIMITER '|' NULL '';查看关闭Dynamic Join Filter功能的情况下，Q17查询的执行耗时。具体步骤如下：关闭Dynamic Join Filter功能：SET adbpg_enable_dynamic_join_filter TO off;执行TPC-H Q17查询：SELECT sum(l_extendedprice) / 7.0 as avg_yearly FROM lineitem, part WHERE p_partkey = l_partkey and p_brand = 'Brand#54' and p_container = 'SM CAN' and l_quantity < ( SELECT 0.2 * avg(l_quantity) FROM lineitem WHERE l_partkey = p_partkey );返回结果如下，查询耗时为3468ms： avg_yearly --------------------- 336452.465714285714 (1 row) Time: 3468.411 ms查看开启Dynamic Join Filter功能的情况下，Q17查询的执行耗时。具体步骤如下：开启Dynamic Join Filter功能：SET adbpg_enable_dynamic_join_filter TO on;执行TPC-H Q17查询：SELECT sum(l_extendedprice) / 7.0 as avg_yearly FROM lineitem, part WHERE p_partkey = l_partkey and p_brand = 'Brand#54' and p_container = 'SM CAN' and l_quantity < ( SELECT 0.2 * avg(l_quantity) FROM lineitem WHERE l_partkey = p_partkey );返回结果如下，查询耗时为305ms： avg_yearly --------------------- 336452.465714285714 (1 row) Time: 305.632 ms通过以上示例可以看出，开启Dynamic Join Filter功能后，执行时间从3468ms降低到305ms，有效地提升了执行性能。