diff --git a/docs/en/administrator-guide/variables.md b/docs/en/administrator-guide/variables.md index 5914df91c5035f..ed8a513556f7cf 100644 --- a/docs/en/administrator-guide/variables.md +++ b/docs/en/administrator-guide/variables.md @@ -85,6 +85,18 @@ SET exec_mem_limit = 10 * 1024 * 1024 * 1024; SET forward_to_master = concat('tr', 'u', 'e'); ``` +### Set variables in the query statement + +In some scenarios, we may need to set variables specifically for certain queries. +The SET_VAR hint sets the session value of a system variable temporarily (for the duration of a single statement). Examples: + +``` +SELECT /*+ SET_VAR(exec_mem_limit = 8589934592) */ name FROM people ORDER BY name; +SELECT /*+ SET_VAR(query_timeout = 1) */ sleep(3); +``` + +Note that the comment must start with /*+ and can only follow the SELECT. + ## Supported variables * `SQL_AUTO_IS_NULL` diff --git a/docs/zh-CN/administrator-guide/variables.md b/docs/zh-CN/administrator-guide/variables.md index 5e780f9b10bba7..8674a8cced9be4 100644 --- a/docs/zh-CN/administrator-guide/variables.md +++ b/docs/zh-CN/administrator-guide/variables.md @@ -85,6 +85,18 @@ SET exec_mem_limit = 10 * 1024 * 1024 * 1024; SET forward_to_master = concat('tr', 'u', 'e'); ``` +### 在查询语句中设置变量 + +在一些场景中，我们可能需要对某些查询有针对性的设置变量。 +通过使用SET_VAR提示可以在查询中设置会话变量（在单个语句内生效）。例子： + +``` +SELECT /*+ SET_VAR(exec_mem_limit = 8589934592) */ name FROM people ORDER BY name; +SELECT /*+ SET_VAR(query_timeout = 1) */ sleep(3); +``` + +注意注释必须以/*+ 开头，并且只能跟随在SELECT之后。 + ## 支持的变量 * `SQL_AUTO_IS_NULL` diff --git a/fe/fe-core/src/main/cup/sql_parser.cup b/fe/fe-core/src/main/cup/sql_parser.cup index c7d073bf8a74bb..ce739bc1339297 100644 --- a/fe/fe-core/src/main/cup/sql_parser.cup +++ b/fe/fe-core/src/main/cup/sql_parser.cup @@ -20,6 +20,7 @@ package org.apache.doris.analysis; import java.math.BigDecimal; import java.util.ArrayList; import java.util.HashSet; +import java.util.HashMap; import java.util.List; import java.util.Map; @@ -255,7 +256,7 @@ terminal String KW_ADD, KW_ADMIN, KW_AFTER, KW_AGGREGATE, KW_ALL, KW_ALTER, KW_A KW_RANDOM, KW_RANGE, KW_READ, KW_RECOVER, KW_REGEXP, KW_RELEASE, KW_RENAME, KW_REPAIR, KW_REPEATABLE, KW_REPOSITORY, KW_REPOSITORIES, KW_REPLACE, KW_REPLACE_IF_NOT_NULL, KW_REPLICA, KW_RESOURCE, KW_RESOURCES, KW_RESTORE, KW_RETURNS, KW_RESUME, KW_REVOKE, KW_RIGHT, KW_ROLE, KW_ROLES, KW_ROLLBACK, KW_ROLLUP, KW_ROUTINE, KW_ROW, KW_ROWS, - KW_SCHEMA, KW_SCHEMAS, KW_SECOND, KW_SELECT, KW_SEMI, KW_SERIALIZABLE, KW_SESSION, KW_SET, KW_SETS, KW_SHOW, KW_SIGNED, + KW_SCHEMA, KW_SCHEMAS, KW_SECOND, KW_SELECT, KW_SEMI, KW_SERIALIZABLE, KW_SESSION, KW_SET, KW_SETS, KW_SET_VAR, KW_SHOW, KW_SIGNED, KW_SMALLINT, KW_SNAPSHOT, KW_SONAME, KW_SPLIT, KW_START, KW_STATUS, KW_STOP, KW_STORAGE, KW_STRING, KW_SUM, KW_SUPERUSER, KW_SYNC, KW_SYSTEM, KW_TABLE, KW_TABLES, KW_TABLET, KW_TASK, KW_TEMPORARY, KW_TERMINATED, KW_THAN, KW_TIME, KW_THEN, KW_TIMESTAMP, KW_TINYINT, @@ -380,6 +381,7 @@ nonterminal InlineViewRef inline_view_ref; nonterminal JoinOperator join_operator; nonterminal ArrayList opt_plan_hints; nonterminal ArrayList opt_sort_hints; +nonterminal HashMap opt_select_hints; nonterminal Expr sign_chain_expr; nonterminal Qualifier opt_set_qualifier; nonterminal Operation set_op; @@ -3298,21 +3300,37 @@ expr_or_default ::= ; select_clause ::= - KW_SELECT select_list:l + KW_SELECT opt_select_hints:hints select_list:l {: + l.setOptHints(hints); RESULT = l; :} - | KW_SELECT KW_ALL select_list:l + | KW_SELECT opt_select_hints:hints KW_ALL select_list:l {: + l.setOptHints(hints); RESULT = l; :} - | KW_SELECT KW_DISTINCT select_list:l + | KW_SELECT opt_select_hints:hints KW_DISTINCT select_list:l {: + l.setOptHints(hints); l.setIsDistinct(true); RESULT = l; :} ; +opt_select_hints ::= + COMMENTED_PLAN_HINT_START KW_SET_VAR LPAREN ident_or_text:k EQUAL literal:v RPAREN COMMENTED_PLAN_HINT_END + {: + HashMap map = new HashMap(); + map.put(k, v.getStringValue()); + RESULT = map; + :} + | /* empty */ + {: + RESULT = null; + :} + ; + select_list ::= select_sublist:list {: diff --git a/fe/fe-core/src/main/java/org/apache/doris/analysis/SelectList.java b/fe/fe-core/src/main/java/org/apache/doris/analysis/SelectList.java index ab1c859a573f6a..afa7dcec580387 100644 --- a/fe/fe-core/src/main/java/org/apache/doris/analysis/SelectList.java +++ b/fe/fe-core/src/main/java/org/apache/doris/analysis/SelectList.java @@ -24,12 +24,14 @@ import com.google.common.collect.Lists; import java.util.List; +import java.util.Map; /** * Select list items plus distinct clause. */ public class SelectList { private boolean isDistinct; + private Map optHints; // /////////////////////////////////////// // BEGIN: Members that need to be reset() @@ -72,7 +74,15 @@ public boolean isDistinct() { public void setIsDistinct(boolean value) { isDistinct = value; } - + + public Map getOptHints() { + return optHints; + } + + public void setOptHints(Map optHints) { + this.optHints = optHints; + } + public void reset() { for (SelectListItem item : items) { if (!item.isStar()) { diff --git a/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java b/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java index 5674661774dba0..fdff35aa38fe85 100644 --- a/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java +++ b/fe/fe-core/src/main/java/org/apache/doris/qe/StmtExecutor.java @@ -36,6 +36,8 @@ import org.apache.doris.analysis.StmtRewriter; import org.apache.doris.analysis.UnsupportedStmt; import org.apache.doris.analysis.UseStmt; +import org.apache.doris.analysis.SetVar; +import org.apache.doris.analysis.StringLiteral; import org.apache.doris.catalog.Catalog; import org.apache.doris.catalog.Column; import org.apache.doris.catalog.Database; @@ -238,8 +240,19 @@ public void execute() throws Exception { context.setQueryId(new TUniqueId(uuid.getMostSignificantBits(), uuid.getLeastSignificantBits())); try { + // support select hint e.g. select /*+ SET_VAR(query_timeout=1) */ sleep(3); + SessionVariable sessionVariable = context.getSessionVariable(); + if (parsedStmt != null && parsedStmt instanceof SelectStmt) { + SelectStmt selectStmt = (SelectStmt) parsedStmt; + Map optHints = selectStmt.getSelectList().getOptHints(); + if(optHints != null) { + for (String key : optHints.keySet()) { + VariableMgr.setVar(sessionVariable, new SetVar(key, new StringLiteral(optHints.get(key)))); + } + } + } // analyze this query - analyze(context.getSessionVariable().toThrift()); + analyze(sessionVariable.toThrift()); if (isForwardToMaster()) { forwardToMaster(); diff --git a/fe/fe-core/src/main/jflex/sql_scanner.flex b/fe/fe-core/src/main/jflex/sql_scanner.flex index 21371ecb58962d..bbd0435ec11751 100644 --- a/fe/fe-core/src/main/jflex/sql_scanner.flex +++ b/fe/fe-core/src/main/jflex/sql_scanner.flex @@ -327,6 +327,7 @@ import org.apache.doris.qe.SqlModeHelper; keywordMap.put("serializable", new Integer(SqlParserSymbols.KW_SERIALIZABLE)); keywordMap.put("session", new Integer(SqlParserSymbols.KW_SESSION)); keywordMap.put("set", new Integer(SqlParserSymbols.KW_SET)); + keywordMap.put("set_var", new Integer(SqlParserSymbols.KW_SET_VAR)); keywordMap.put("sets", new Integer(SqlParserSymbols.KW_SETS)); keywordMap.put("show", new Integer(SqlParserSymbols.KW_SHOW)); keywordMap.put("signed", new Integer(SqlParserSymbols.KW_SIGNED)); diff --git a/fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java b/fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java old mode 100755 new mode 100644 index e6c88909b6d0c9..9a65be502423b3 --- a/fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java +++ b/fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java @@ -19,6 +19,8 @@ import org.apache.doris.common.AnalysisException; import org.apache.doris.qe.ConnectContext; +import org.apache.doris.planner.Planner; +import org.apache.doris.qe.VariableMgr; import org.apache.doris.utframe.DorisAssert; import org.apache.doris.utframe.UtFrameUtils; @@ -453,4 +455,26 @@ public void testDeleteSign() throws Exception { String sql4 = " SELECT * FROM table1 table2"; Assert.assertTrue(dorisAssert.query(sql4).explainQuery().contains("`table2`.`__DORIS_DELETE_SIGN__` = 0")); } + + @Test + public void testSelectHintSetVar() throws Exception { + String sql = "SELECT sleep(3);"; + Planner planner = dorisAssert.query(sql).internalExecuteOneAndGetPlan(); + Assert.assertEquals(VariableMgr.getDefaultSessionVariable().getQueryTimeoutS(), + planner.getPlannerContext().getQueryOptions().query_timeout); + + sql = "SELECT /*+ SET_VAR(query_timeout = 1) */ sleep(3);"; + planner = dorisAssert.query(sql).internalExecuteOneAndGetPlan(); + Assert.assertEquals(1, planner.getPlannerContext().getQueryOptions().query_timeout); + + sql = "select * from db1.partition_table where datekey=20200726"; + planner = dorisAssert.query(sql).internalExecuteOneAndGetPlan(); + Assert.assertEquals(VariableMgr.getDefaultSessionVariable().getMaxExecMemByte(), + planner.getPlannerContext().getQueryOptions().mem_limit); + + sql = "select /*+ SET_VAR(exec_mem_limit = 8589934592) */ poi_id, count(*) from db1.partition_table " + + "where datekey=20200726 group by 1"; + planner = dorisAssert.query(sql).internalExecuteOneAndGetPlan(); + Assert.assertEquals(8589934592L, planner.getPlannerContext().getQueryOptions().mem_limit); + } } diff --git a/fe/fe-core/src/test/java/org/apache/doris/utframe/DorisAssert.java b/fe/fe-core/src/test/java/org/apache/doris/utframe/DorisAssert.java index 6edf38d8620753..4ec7c03ee3fc47 100644 --- a/fe/fe-core/src/test/java/org/apache/doris/utframe/DorisAssert.java +++ b/fe/fe-core/src/test/java/org/apache/doris/utframe/DorisAssert.java @@ -23,10 +23,14 @@ import org.apache.doris.analysis.CreateMaterializedViewStmt; import org.apache.doris.analysis.CreateTableStmt; import org.apache.doris.analysis.DropTableStmt; +import org.apache.doris.analysis.SqlParser; +import org.apache.doris.analysis.SqlScanner; +import org.apache.doris.analysis.StatementBase; import org.apache.doris.catalog.Catalog; import org.apache.doris.cluster.ClusterNamespace; import org.apache.doris.common.AnalysisException; import org.apache.doris.common.Config; +import org.apache.doris.common.util.SqlParserUtils; import org.apache.doris.planner.Planner; import org.apache.doris.qe.ConnectContext; import org.apache.doris.qe.QueryState; @@ -38,6 +42,8 @@ import org.junit.Assert; import java.io.IOException; +import java.io.StringReader; +import java.util.List; import java.util.Map; import java.util.stream.Stream; @@ -162,5 +168,15 @@ private String internalExecute(String sql) throws Exception { System.out.println(explainString); return explainString; } + + public Planner internalExecuteOneAndGetPlan() throws Exception{ + SqlScanner input = new SqlScanner(new StringReader(sql), ctx.getSessionVariable().getSqlMode()); + SqlParser parser = new SqlParser(input); + List stmts = SqlParserUtils.getMultiStmts(parser); + StmtExecutor stmtExecutor = new StmtExecutor(connectContext, stmts.get(0)); + stmtExecutor.execute(); + + return stmtExecutor.planner(); + } } }