From 1e6115cb99a1286a61cb0a6a088f7476da29d0b9 Mon Sep 17 00:00:00 2001 From: "Zheng (Zane) Li" Date: Fri, 29 Apr 2022 16:57:03 +0000 Subject: [PATCH 10/10] Fail replication worker on DDL command that rewrites table using volatile functions, such as ALTER TABLE tab ADD COLUMN col DEFAULT volatile_expr. This is to avoid data mismatch compared to the publisher. We can potentially unblock this type of command when table rewrite is supported in logical replication. --- src/backend/replication/logical/worker.c | 44 ++++++++++++++++++++++++ src/test/subscription/t/030_rep_ddls.pl | 22 ++++++++++++ 2 files changed, 66 insertions(+) diff --git a/src/backend/replication/logical/worker.c b/src/backend/replication/logical/worker.c index f5274531b7..93281cb88d 100644 --- a/src/backend/replication/logical/worker.c +++ b/src/backend/replication/logical/worker.c @@ -157,6 +157,7 @@ #include "nodes/makefuncs.h" #include "optimizer/optimizer.h" #include "parser/analyze.h" +#include "parser/parse_expr.h" #include "pgstat.h" #include "postmaster/bgworker.h" #include "postmaster/interrupt.h" @@ -2548,6 +2549,8 @@ apply_execute_sql_command(const char *cmdstr, const char *role, const char *sear commandTag = CreateCommandTag((Node *)command); + /* The following DDL commands need special handling */ + /* * Remember the schemaname and relname if the cmd is going to create a table * because we will need them for some post-processing after we @@ -2595,6 +2598,47 @@ apply_execute_sql_command(const char *cmdstr, const char *role, const char *sear sstmt->intoClause->skipData = true; } } + /* + * ALTER TABLE ADD COLUMN col DEFAULT volatile_expr is not supported. + * Until we support logical replication of table rewrite, see ATRewriteTables() + * for details on table rewrite. + */ + else if (commandTag == CMDTAG_ALTER_TABLE) + { + AlterTableStmt *atstmt = (AlterTableStmt *) command->stmt; + ListCell *lc; + + foreach(lc, atstmt->cmds) + { + AlterTableCmd *cmd = lfirst_node(AlterTableCmd, lc); + + if (cmd->subtype == AT_AddColumn) + { + ColumnDef *colDef; + ListCell *c; + + colDef = castNode(ColumnDef, cmd->def); + foreach(c, colDef->constraints) + { + Constraint *con = lfirst_node(Constraint, c); + + if (con->contype == CONSTR_DEFAULT) + { + Node *expr; + ParseState *pstate = make_parsestate(NULL); + + expr = transformExpr(pstate, copyObject(con->raw_expr), EXPR_KIND_COLUMN_DEFAULT); + if (contain_volatile_functions(expr)) + { + elog(ERROR, + "Do not support replication of DDL statement that rewrites table using volatile functions: %s", + cmdstr); + } + } + } + } + } + } /* * Set up a snapshot if parse analysis/planning will need one. diff --git a/src/test/subscription/t/030_rep_ddls.pl b/src/test/subscription/t/030_rep_ddls.pl index 34b9d51eb1..b4df1bfefd 100644 --- a/src/test/subscription/t/030_rep_ddls.pl +++ b/src/test/subscription/t/030_rep_ddls.pl @@ -386,7 +386,29 @@ $node_publisher->wait_for_catchup('mysub'); $result = $node_subscriber->safe_psql('postgres', "SELECT count(*) FROM s1.proc_table where c3 = 22;"); is($result, qq(1), 'DDLs in procedure are replicated'); +# Test Alter table alter column type stmt is replicated +$node_publisher->safe_psql('postgres', "ALTER TABLE test_rep ALTER COLUMN name type TEXT;"); + +$node_publisher->wait_for_catchup('mysub'); + +$result = $node_subscriber->safe_psql('postgres', "SELECT data_type FROM information_schema.columns WHERE table_name = 'test_rep' and column_name = 'name';"); +is($result, qq(text), 'Alter table column type stmt is replicated'); + +# Test Alter table add column default 0.01 is replicated +$node_publisher->safe_psql('postgres', "ALTER TABLE test_rep ADD COLUMN non_volatile double precision DEFAULT 0.01;"); + +$node_publisher->wait_for_catchup('mysub'); + +$result = $node_subscriber->safe_psql('postgres', "SELECT count(*) from test_rep where non_volatile = 0.01;"); +is($result, qq(2), 'Alter table add column default 0.01 is replicated'); + #TODO TEST certain DDLs are not replicated +# Test DDL statement that rewrites table with volatile functions are not replicated +$node_publisher->safe_psql('postgres', "ALTER TABLE test_rep ADD COLUMN volatile double precision DEFAULT 3 * random();"); +$result = $node_publisher->safe_psql('postgres', "SELECT count(*) FROM information_schema.columns WHERE table_name = 'test_rep' and column_name = 'volatile';"); +is($result, qq(1), 'Alter table add column default random() is executed on the publisher DB.'); + +$result = $node_subscriber->wait_for_log("Do not support replication of DDL statement that rewrites table using volatile functions", $result); pass "DDL replication tests passed!"; -- 2.32.0