From 81ce000067e3c7d5f08adb615806453567ee142f Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Thu, 13 Jul 2023 13:03:34 -0700 Subject: [PATCH] Handle DROP DATABASE getting interrupted Until now, when DROP DATABASE got interrupted in the wrong moment, the removal of the pg_database row would also roll back, even though some irreversible steps have already been taken. E.g. DropDatabaseBuffers() might have thrown out dirty buffers, or files could have been unlinked. But we continued to allow connections to such a corrupted database. To fix this, mark databases invalid with an in-place update, just before starting to perform irreversible steps. As we can't add a new column in the back branches, we use pg_database.datconnlimit = -2 for this purpose. An invalid database cannot be connected to anymore, but can still be dropped. Unfortunately we can't easily add output to psql's \l to indicate that some database is invalid, it doesn't fit in any of the existing columns. Add tests verifying that a interrupted DROP DATABASE is handled correctly in the backend and in various tools. Reported-by: Evgeny Morozov Author: Andres Freund Reviewed-by: Daniel Gustafsson Reviewed-by: Thomas Munro Discussion: https://postgr.es/m/20230509004637.cgvmfwrbht7xm7p6@awork3.anarazel.de Discussion: https://postgr.es/m/20230314174521.74jl6ffqsee5mtug@awork3.anarazel.de Backpatch: 11-, bug present in all supported versions --- doc/src/sgml/catalogs.sgml | 3 +- src/backend/commands/dbcommands.c | 100 +++++++++++-- src/backend/commands/vacuum.c | 14 ++ src/backend/postmaster/autovacuum.c | 12 ++ src/backend/utils/init/postinit.c | 10 ++ src/bin/pg_dump/pg_dumpall.c | 4 +- src/bin/pg_dump/t/002_pg_dump.pl | 21 ++- src/bin/scripts/clusterdb.c | 4 +- src/bin/scripts/reindexdb.c | 4 +- src/bin/scripts/t/011_clusterdb_all.pl | 15 +- src/bin/scripts/t/050_dropdb.pl | 11 +- src/bin/scripts/t/091_reindexdb_all.pl | 15 +- src/bin/scripts/t/101_vacuumdb_all.pl | 15 +- src/bin/scripts/vacuumdb.c | 2 +- src/include/catalog/pg_database.h | 20 ++- src/test/recovery/t/037_invalid_database.pl | 157 ++++++++++++++++++++ 16 files changed, 380 insertions(+), 27 deletions(-) create mode 100644 src/test/recovery/t/037_invalid_database.pl diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index ebb5a4f3ffd..aaf8361ac8a 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -2951,7 +2951,8 @@ SCRAM-SHA-256$<iteration count>:&l Sets maximum number of concurrent connections that can be made - to this database. -1 means no limit. + to this database. -1 means no limit, -2 indicates the database is + invalid. diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c index abe524f1121..d68a570ee15 100644 --- a/src/backend/commands/dbcommands.c +++ b/src/backend/commands/dbcommands.c @@ -140,7 +140,7 @@ createdb(ParseState *pstate, const CreatedbStmt *stmt) int encoding = -1; bool dbistemplate = false; bool dballowconnections = true; - int dbconnlimit = -1; + int dbconnlimit = DATCONNLIMIT_UNLIMITED; int notherbackends; int npreparedxacts; createdb_failure_params fparms; @@ -309,7 +309,7 @@ createdb(ParseState *pstate, const CreatedbStmt *stmt) if (dconnlimit && dconnlimit->arg) { dbconnlimit = defGetInt32(dconnlimit); - if (dbconnlimit < -1) + if (dbconnlimit < DATCONNLIMIT_UNLIMITED) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("invalid connection limit: %d", dbconnlimit))); @@ -357,6 +357,16 @@ createdb(ParseState *pstate, const CreatedbStmt *stmt) errmsg("template database \"%s\" does not exist", dbtemplate))); + /* + * If the source database was in the process of being dropped, we can't + * use it as a template. + */ + if (database_is_invalid_oid(src_dboid)) + ereport(ERROR, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("cannot use invalid database \"%s\" as template", dbtemplate), + errhint("Use DROP DATABASE to drop invalid databases.")); + /* * Permission check: to copy a DB that's not marked datistemplate, you * must be superuser or the owner thereof. @@ -817,6 +827,7 @@ dropdb(const char *dbname, bool missing_ok, bool force) bool db_istemplate; Relation pgdbrel; HeapTuple tup; + Form_pg_database datform; int notherbackends; int npreparedxacts; int nslots, @@ -932,17 +943,6 @@ dropdb(const char *dbname, bool missing_ok, bool force) dbname), errdetail_busy_db(notherbackends, npreparedxacts))); - /* - * Remove the database's tuple from pg_database. - */ - tup = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(db_id)); - if (!HeapTupleIsValid(tup)) - elog(ERROR, "cache lookup failed for database %u", db_id); - - CatalogTupleDelete(pgdbrel, &tup->t_self); - - ReleaseSysCache(tup); - /* * Delete any comments or security labels associated with the database. */ @@ -959,6 +959,32 @@ dropdb(const char *dbname, bool missing_ok, bool force) */ dropDatabaseDependencies(db_id); + tup = SearchSysCacheCopy1(DATABASEOID, ObjectIdGetDatum(db_id)); + if (!HeapTupleIsValid(tup)) + elog(ERROR, "cache lookup failed for database %u", db_id); + datform = (Form_pg_database) GETSTRUCT(tup); + + /* + * Except for the deletion of the catalog row, subsequent actions are not + * transactional (consider DropDatabaseBuffers() discarding modified + * buffers). But we might crash or get interrupted below. To prevent + * accesses to a database with invalid contents, mark the database as + * invalid using an in-place update. + * + * We need to flush the WAL before continuing, to guarantee the + * modification is durable before performing irreversible filesystem + * operations. + */ + datform->datconnlimit = DATCONNLIMIT_INVALID_DB; + heap_inplace_update(pgdbrel, tup); + XLogFlush(XactLastRecEnd); + + /* + * Also delete the tuple - transactionally. If this transaction commits, + * the row will be gone, but if we fail, dropdb() can be invoked again. + */ + CatalogTupleDelete(pgdbrel, &tup->t_self); + /* * Drop db-specific replication slots. */ @@ -1481,7 +1507,7 @@ AlterDatabase(ParseState *pstate, AlterDatabaseStmt *stmt, bool isTopLevel) ListCell *option; bool dbistemplate = false; bool dballowconnections = true; - int dbconnlimit = -1; + int dbconnlimit = DATCONNLIMIT_UNLIMITED; DefElem *distemplate = NULL; DefElem *dallowconnections = NULL; DefElem *dconnlimit = NULL; @@ -1564,7 +1590,7 @@ AlterDatabase(ParseState *pstate, AlterDatabaseStmt *stmt, bool isTopLevel) if (dconnlimit && dconnlimit->arg) { dbconnlimit = defGetInt32(dconnlimit); - if (dbconnlimit < -1) + if (dbconnlimit < DATCONNLIMIT_UNLIMITED) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("invalid connection limit: %d", dbconnlimit))); @@ -1591,6 +1617,14 @@ AlterDatabase(ParseState *pstate, AlterDatabaseStmt *stmt, bool isTopLevel) datform = (Form_pg_database) GETSTRUCT(tuple); dboid = datform->oid; + if (database_is_invalid_form(datform)) + { + ereport(FATAL, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("cannot alter invalid database \"%s\"", stmt->dbname), + errhint("Use DROP DATABASE to drop invalid databases.")); + } + if (!pg_database_ownercheck(dboid, GetUserId())) aclcheck_error(ACLCHECK_NOT_OWNER, OBJECT_DATABASE, stmt->dbname); @@ -2170,6 +2204,42 @@ get_database_name(Oid dbid) return result; } + +/* + * While dropping a database the pg_database row is marked invalid, but the + * catalog contents still exist. Connections to such a database are not + * allowed. + */ +bool +database_is_invalid_form(Form_pg_database datform) +{ + return datform->datconnlimit == DATCONNLIMIT_INVALID_DB; +} + + +/* + * Convenience wrapper around database_is_invalid_form() + */ +bool +database_is_invalid_oid(Oid dboid) +{ + HeapTuple dbtup; + Form_pg_database dbform; + bool invalid; + + dbtup = SearchSysCache1(DATABASEOID, ObjectIdGetDatum(dboid)); + if (!HeapTupleIsValid(dbtup)) + elog(ERROR, "cache lookup failed for database %u", dboid); + dbform = (Form_pg_database) GETSTRUCT(dbtup); + + invalid = database_is_invalid_form(dbform); + + ReleaseSysCache(dbtup); + + return invalid; +} + + /* * recovery_create_dbdir() * diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c index 52cd2b431c5..b92e6c1c6aa 100644 --- a/src/backend/commands/vacuum.c +++ b/src/backend/commands/vacuum.c @@ -1596,6 +1596,20 @@ vac_truncate_clog(TransactionId frozenXID, Assert(TransactionIdIsNormal(datfrozenxid)); Assert(MultiXactIdIsValid(datminmxid)); + /* + * If database is in the process of getting dropped, or has been + * interrupted while doing so, no connections to it are possible + * anymore. Therefore we don't need to take it into account here. + * Which is good, because it can't be processed by autovacuum either. + */ + if (database_is_invalid_form((Form_pg_database) dbform)) + { + elog(DEBUG2, + "skipping invalid database \"%s\" while computing relfrozenxid", + NameStr(dbform->datname)); + continue; + } + /* * If things are working properly, no database should have a * datfrozenxid or datminmxid that is "in the future". However, such diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c index 2689c68e3b4..a73b6cf92f8 100644 --- a/src/backend/postmaster/autovacuum.c +++ b/src/backend/postmaster/autovacuum.c @@ -1890,6 +1890,18 @@ get_database_list(void) avw_dbase *avdb; MemoryContext oldcxt; + /* + * If database has partially been dropped, we can't, nor need to, + * vacuum it. + */ + if (database_is_invalid_form(pgdatabase)) + { + elog(DEBUG2, + "autovacuum: skipping invalid database \"%s\"", + NameStr(pgdatabase->datname)); + continue; + } + /* * Allocate our results in the caller's context, not the * transaction's. We do this inside the loop, and restore the original diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c index 01463af22f8..97e2615773c 100644 --- a/src/backend/utils/init/postinit.c +++ b/src/backend/utils/init/postinit.c @@ -972,6 +972,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username, if (!bootstrap) { HeapTuple tuple; + Form_pg_database datform; tuple = GetDatabaseTuple(dbname); if (!HeapTupleIsValid(tuple) || @@ -981,6 +982,15 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username, (errcode(ERRCODE_UNDEFINED_DATABASE), errmsg("database \"%s\" does not exist", dbname), errdetail("It seems to have just been dropped or renamed."))); + + datform = (Form_pg_database) GETSTRUCT(tuple); + if (database_is_invalid_form(datform)) + { + ereport(FATAL, + errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), + errmsg("cannot connect to invalid database \"%s\"", dbname), + errhint("Use DROP DATABASE to drop invalid databases.")); + } } /* diff --git a/src/bin/pg_dump/pg_dumpall.c b/src/bin/pg_dump/pg_dumpall.c index 0bc74da9cfb..a410247a2b6 100644 --- a/src/bin/pg_dump/pg_dumpall.c +++ b/src/bin/pg_dump/pg_dumpall.c @@ -1320,7 +1320,7 @@ dropDBs(PGconn *conn) res = executeQuery(conn, "SELECT datname " "FROM pg_database d " - "WHERE datallowconn " + "WHERE datallowconn AND datconnlimit != -2 " "ORDER BY datname"); if (PQntuples(res) > 0) @@ -1473,7 +1473,7 @@ dumpDatabases(PGconn *conn) res = executeQuery(conn, "SELECT datname " "FROM pg_database d " - "WHERE datallowconn " + "WHERE datallowconn AND datconnlimit != -2 " "ORDER BY (datname <> 'template1'), datname"); if (PQntuples(res) > 0) diff --git a/src/bin/pg_dump/t/002_pg_dump.pl b/src/bin/pg_dump/t/002_pg_dump.pl index 4beed0caa90..c24fda379f4 100644 --- a/src/bin/pg_dump/t/002_pg_dump.pl +++ b/src/bin/pg_dump/t/002_pg_dump.pl @@ -1430,6 +1430,17 @@ my %tests = ( }, }, + 'CREATE DATABASE regression_invalid...' => { + create_order => 1, + create_sql => q( + CREATE DATABASE regression_invalid; + UPDATE pg_database SET datconnlimit = -2 WHERE datname = 'regression_invalid'), + regexp => qr/^CREATE DATABASE regression_invalid/m, + not_like => { + pg_dumpall_dbprivs => 1, + }, + }, + 'CREATE ACCESS METHOD gist2' => { create_order => 52, create_sql => @@ -3521,7 +3532,7 @@ $node->psql('postgres', 'create database regress_pg_dump_test;'); # Start with number of command_fails_like()*2 tests below (each # command_fails_like is actually 2 tests) -my $num_tests = 12; +my $num_tests = 14; foreach my $run (sort keys %pgdump_runs) { @@ -3649,6 +3660,14 @@ command_fails_like( qr/\Qpg_dump: error: connection to database "qqq" failed: FATAL: database "qqq" does not exist\E/, 'connecting to a non-existent database'); +######################################### +# Test connecting to an invalid database + +command_fails_like( + [ 'pg_dump', '-p', "$port", '-d', 'regression_invalid' ], + qr/pg_dump: error: connection to database .* failed: FATAL: cannot connect to invalid database "regression_invalid"/, + 'connecting to an invalid database'); + ######################################### # Test connecting with an unprivileged user diff --git a/src/bin/scripts/clusterdb.c b/src/bin/scripts/clusterdb.c index 2f786e61037..949928f67d3 100644 --- a/src/bin/scripts/clusterdb.c +++ b/src/bin/scripts/clusterdb.c @@ -237,7 +237,9 @@ cluster_all_databases(ConnParams *cparams, const char *progname, int i; conn = connectMaintenanceDatabase(cparams, progname, echo); - result = executeQuery(conn, "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", echo); + result = executeQuery(conn, + "SELECT datname FROM pg_database WHERE datallowconn AND datconnlimit <> -2 ORDER BY 1;", + echo); PQfinish(conn); for (i = 0; i < PQntuples(result); i++) diff --git a/src/bin/scripts/reindexdb.c b/src/bin/scripts/reindexdb.c index c543d76b4f8..b2e1b9cd1ba 100644 --- a/src/bin/scripts/reindexdb.c +++ b/src/bin/scripts/reindexdb.c @@ -720,7 +720,9 @@ reindex_all_databases(ConnParams *cparams, int i; conn = connectMaintenanceDatabase(cparams, progname, echo); - result = executeQuery(conn, "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", echo); + result = executeQuery(conn, + "SELECT datname FROM pg_database WHERE datallowconn AND datconnlimit <> -2 ORDER BY 1;", + echo); PQfinish(conn); for (i = 0; i < PQntuples(result); i++) diff --git a/src/bin/scripts/t/011_clusterdb_all.pl b/src/bin/scripts/t/011_clusterdb_all.pl index efd541bc4d6..8ac734bdfa2 100644 --- a/src/bin/scripts/t/011_clusterdb_all.pl +++ b/src/bin/scripts/t/011_clusterdb_all.pl @@ -3,7 +3,7 @@ use warnings; use PostgresNode; use TestLib; -use Test::More tests => 2; +use Test::More tests => 4; my $node = get_new_node('main'); $node->init; @@ -17,3 +17,16 @@ $node->issues_sql_like( [ 'clusterdb', '-a' ], qr/statement: CLUSTER.*statement: CLUSTER/s, 'cluster all databases'); + +$node->safe_psql( + 'postgres', q( + CREATE DATABASE regression_invalid; + UPDATE pg_database SET datconnlimit = -2 WHERE datname = 'regression_invalid'; +)); +$node->command_ok([ 'clusterdb', '-a' ], + 'invalid database not targeted by clusterdb -a'); + +# Doesn't quite belong here, but don't want to waste time by creating an +# invalid database in 010_clusterdb.pl as well. +$node->command_fails([ 'clusterdb', '-d', 'regression_invalid'], + 'clusterdb cannot target invalid database'); diff --git a/src/bin/scripts/t/050_dropdb.pl b/src/bin/scripts/t/050_dropdb.pl index c51babe093f..9f5f65e8530 100644 --- a/src/bin/scripts/t/050_dropdb.pl +++ b/src/bin/scripts/t/050_dropdb.pl @@ -3,7 +3,7 @@ use warnings; use PostgresNode; use TestLib; -use Test::More tests => 13; +use Test::More tests => 14; program_help_ok('dropdb'); program_version_ok('dropdb'); @@ -27,3 +27,12 @@ $node->issues_sql_like( $node->command_fails([ 'dropdb', 'nonexistent' ], 'fails with nonexistent database'); + +# check that invalid database can be dropped with dropdb +$node->safe_psql( + 'postgres', q( + CREATE DATABASE regression_invalid; + UPDATE pg_database SET datconnlimit = -2 WHERE datname = 'regression_invalid'; +)); +$node->command_ok([ 'dropdb', 'regression_invalid' ], + 'invalid database can be dropped'); diff --git a/src/bin/scripts/t/091_reindexdb_all.pl b/src/bin/scripts/t/091_reindexdb_all.pl index 8e6041460c5..6990fcea9ae 100644 --- a/src/bin/scripts/t/091_reindexdb_all.pl +++ b/src/bin/scripts/t/091_reindexdb_all.pl @@ -2,7 +2,7 @@ use strict; use warnings; use PostgresNode; -use Test::More tests => 2; +use Test::More tests => 4; my $node = get_new_node('main'); $node->init; @@ -14,3 +14,16 @@ $node->issues_sql_like( [ 'reindexdb', '-a' ], qr/statement: REINDEX.*statement: REINDEX/s, 'reindex all databases'); + +$node->safe_psql( + 'postgres', q( + CREATE DATABASE regression_invalid; + UPDATE pg_database SET datconnlimit = -2 WHERE datname = 'regression_invalid'; +)); +$node->command_ok([ 'reindexdb', '-a' ], + 'invalid database not targeted by reindexdb -a'); + +# Doesn't quite belong here, but don't want to waste time by creating an +# invalid database in 090_reindexdb.pl as well. +$node->command_fails([ 'reindexdb', '-d', 'regression_invalid'], + 'reindexdb cannot target invalid database'); diff --git a/src/bin/scripts/t/101_vacuumdb_all.pl b/src/bin/scripts/t/101_vacuumdb_all.pl index 43212587e5a..d9055726540 100644 --- a/src/bin/scripts/t/101_vacuumdb_all.pl +++ b/src/bin/scripts/t/101_vacuumdb_all.pl @@ -2,7 +2,7 @@ use strict; use warnings; use PostgresNode; -use Test::More tests => 2; +use Test::More tests => 4; my $node = get_new_node('main'); $node->init; @@ -12,3 +12,16 @@ $node->issues_sql_like( [ 'vacuumdb', '-a' ], qr/statement: VACUUM.*statement: VACUUM/s, 'vacuum all databases'); + +$node->safe_psql( + 'postgres', q( + CREATE DATABASE regression_invalid; + UPDATE pg_database SET datconnlimit = -2 WHERE datname = 'regression_invalid'; +)); +$node->command_ok([ 'vacuumdb', '-a' ], + 'invalid database not targeted by vacuumdb -a'); + +# Doesn't quite belong here, but don't want to waste time by creating an +# invalid database in 010_vacuumdb.pl as well. +$node->command_fails([ 'vacuumdb', '-d', 'regression_invalid'], + 'vacuumdb cannot target invalid database'); diff --git a/src/bin/scripts/vacuumdb.c b/src/bin/scripts/vacuumdb.c index 1cf689cd053..b4de91d6d02 100644 --- a/src/bin/scripts/vacuumdb.c +++ b/src/bin/scripts/vacuumdb.c @@ -718,7 +718,7 @@ vacuum_all_databases(ConnParams *cparams, conn = connectMaintenanceDatabase(cparams, progname, echo); result = executeQuery(conn, - "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", + "SELECT datname FROM pg_database WHERE datallowconn AND datconnlimit <> -2 ORDER BY 1;", echo); PQfinish(conn); diff --git a/src/include/catalog/pg_database.h b/src/include/catalog/pg_database.h index f623ee81b77..f3d171cd80b 100644 --- a/src/include/catalog/pg_database.h +++ b/src/include/catalog/pg_database.h @@ -52,7 +52,10 @@ CATALOG(pg_database,1262,DatabaseRelationId) BKI_SHARED_RELATION BKI_ROWTYPE_OID /* new connections allowed? */ bool datallowconn; - /* max connections allowed (-1=no limit) */ + /* + * Max connections allowed. Negative values have special meaning, see + * DATCONNLIMIT_* defines below. + */ int32 datconnlimit; /* highest OID to consider a system OID */ @@ -80,4 +83,19 @@ CATALOG(pg_database,1262,DatabaseRelationId) BKI_SHARED_RELATION BKI_ROWTYPE_OID */ typedef FormData_pg_database *Form_pg_database; +/* + * Special values for pg_database.datconnlimit. Normal values are >= 0. + */ +#define DATCONNLIMIT_UNLIMITED -1 /* no limit */ + +/* + * A database is set to invalid partway through being dropped. Using + * datconnlimit=-2 for this purpose isn't particularly clean, but is + * backpatchable. + */ +#define DATCONNLIMIT_INVALID_DB -2 + +extern bool database_is_invalid_form(Form_pg_database datform); +extern bool database_is_invalid_oid(Oid dboid); + #endif /* PG_DATABASE_H */ diff --git a/src/test/recovery/t/037_invalid_database.pl b/src/test/recovery/t/037_invalid_database.pl new file mode 100644 index 00000000000..a061fab5fc9 --- /dev/null +++ b/src/test/recovery/t/037_invalid_database.pl @@ -0,0 +1,157 @@ +# Copyright (c) 2023, PostgreSQL Global Development Group +# +# Test we handle interrupted DROP DATABASE correctly. + +use strict; +use warnings; +use PostgreSQL::Test::Cluster; +use PostgreSQL::Test::Utils; +use Test::More; + +my $node = PostgreSQL::Test::Cluster->new('node'); +$node->init; +$node->append_conf( + "postgresql.conf", qq( +autovacuum = off +max_prepared_transactions=5 +log_min_duration_statement=0 +log_connections=on +log_disconnections=on +)); + +$node->start; + + +# First verify that we can't connect to or ALTER an invalid database. Just +# mark the database as invalid ourselves, that's more reliable than hitting the +# required race conditions (see testing further down)... + +$node->safe_psql( + "postgres", qq( +CREATE DATABASE regression_invalid; +UPDATE pg_database SET datconnlimit = -2 WHERE datname = 'regression_invalid'; +)); + +my $psql_stdout = ''; +my $psql_stderr = ''; + +is($node->psql('regression_invalid', '', stderr => \$psql_stderr), + 2, "can't connect to invalid database - error code"); +like( + $psql_stderr, + qr/FATAL:\s+cannot connect to invalid database "regression_invalid"/, + "can't connect to invalid database - error message"); + +is($node->psql('postgres', 'ALTER DATABASE regression_invalid CONNECTION LIMIT 10'), + 2, "can't ALTER invalid database"); + +# check invalid database can't be used as a template +is( $node->psql('postgres', 'CREATE DATABASE copy_invalid TEMPLATE regression_invalid'), + 3, + "can't use invalid database as template"); + + +# Verify that VACUUM ignores an invalid database when computing how much of +# the clog is needed (vac_truncate_clog()). For that we modify the pg_database +# row of the invalid database to have an outdated datfrozenxid. +$psql_stderr = ''; +$node->psql( + 'postgres', + qq( +UPDATE pg_database SET datfrozenxid = '123456' WHERE datname = 'regression_invalid'; +DROP TABLE IF EXISTS foo_tbl; CREATE TABLE foo_tbl(); +VACUUM FREEZE;), + stderr => \$psql_stderr); +unlike( + $psql_stderr, + qr/some databases have not been vacuumed in over 2 billion transactions/, + "invalid databases are ignored by vac_truncate_clog"); + + +# But we need to be able to drop an invalid database. +is( $node->psql( + 'postgres', 'DROP DATABASE regression_invalid', + stdout => \$psql_stdout, + stderr => \$psql_stderr), + 0, + "can DROP invalid database"); + +# Ensure database is gone +is($node->psql('postgres', 'DROP DATABASE regression_invalid'), + 3, "can't drop already dropped database"); + + +# Test that interruption of DROP DATABASE is handled properly. To ensure the +# interruption happens at the appropriate moment, we lock pg_tablespace. DROP +# DATABASE scans pg_tablespace once it has reached the "irreversible" part of +# dropping the database, making it a suitable point to wait. +my $bgpsql_in = ''; +my $bgpsql_out = ''; +my $bgpsql_err = ''; +my $bgpsql_timer = IPC::Run::timer($PostgreSQL::Test::Utils::timeout_default); +my $bgpsql = $node->background_psql('postgres', \$bgpsql_in, \$bgpsql_out, + $bgpsql_timer, on_error_stop => 0); +$bgpsql_out = ''; +$bgpsql_in .= "SELECT pg_backend_pid();\n"; + +pump_until($bgpsql, $bgpsql_timer, \$bgpsql_out, qr/\d/); + +my $pid = $bgpsql_out; +$bgpsql_out = ''; + +# create the database, prevent drop database via lock held by a 2PC transaction +$bgpsql_in .= qq( + CREATE DATABASE regression_invalid_interrupt; + BEGIN; + LOCK pg_tablespace; + PREPARE TRANSACTION 'lock_tblspc'; + \\echo done +); + +ok(pump_until($bgpsql, $bgpsql_timer, \$bgpsql_out, qr/done/), + "blocked DROP DATABASE completion"); +$bgpsql_out = ''; + +# Try to drop. This will wait due to the still held lock. +$bgpsql_in .= qq( + DROP DATABASE regression_invalid_interrupt; + \\echo DROP DATABASE completed +); +$bgpsql->pump_nb; + +# Ensure we're waiting for the lock +$node->poll_query_until('postgres', + qq(SELECT EXISTS(SELECT * FROM pg_locks WHERE NOT granted AND relation = 'pg_tablespace'::regclass AND mode = 'AccessShareLock');) +); + +# and finally interrupt the DROP DATABASE +ok($node->safe_psql('postgres', "SELECT pg_cancel_backend($pid)"), + "canceling DROP DATABASE"); + +# wait for cancellation to be processed +ok( pump_until( + $bgpsql, $bgpsql_timer, \$bgpsql_out, qr/DROP DATABASE completed/), + "cancel processed"); +$bgpsql_out = ''; + +# verify that connection to the database aren't allowed +is($node->psql('regression_invalid_interrupt', ''), + 2, "can't connect to invalid_interrupt database"); + +# To properly drop the database, we need to release the lock previously preventing +# doing so. +$bgpsql_in .= qq( + ROLLBACK PREPARED 'lock_tblspc'; + \\echo ROLLBACK PREPARED +); +ok(pump_until($bgpsql, $bgpsql_timer, \$bgpsql_out, qr/ROLLBACK PREPARED/), + "unblock DROP DATABASE"); +$bgpsql_out = ''; + +is($node->psql('postgres', "DROP DATABASE regression_invalid_interrupt"), + 0, "DROP DATABASE invalid_interrupt"); + +$bgpsql_in .= "\\q\n"; +$bgpsql->finish(); + +done_testing();