I am trying to run a CREATE INDEX CONCURRENTLY command against a Postgres 9.2 database. I implemented a MigrationResolver as shown in issue 655. When this migration step is run via mvn flyway:migrate or similar, the command starts but hangs in waiting mode.
I verified that the command is executing via the pg_stat_activity table:
test_2015_04_13_110536=# select * from pg_stat_activity;
datid | datname | pid | usesysid | usename | application_name | client_addr | client_hostname | client_port | backend_start | xact_start | query_start | state_change | waiting | state | query
-------+------------------------+-------+----------+----------+------------------+-------------+-----------------+-------------+-------------------------------+-------------------------------+-------------------------------+-------------------------------+---------+---------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
21095 | test_2015_04_13_110536 | 56695 | 16385 | postgres | psql | | | -1 | 2015-04-13 11:10:01.127768-06 | 2015-04-13 11:13:08.936651-06 | 2015-04-13 11:13:08.936651-06 | 2015-04-13 11:13:08.936655-06 | f | active | select * from pg_stat_activity;
21095 | test_2015_04_13_110536 | 56824 | 16385 | postgres | | 127.0.0.1 | | 52437 | 2015-04-13 11:12:55.438927-06 | 2015-04-13 11:12:55.476442-06 | 2015-04-13 11:12:55.487139-06 | 2015-04-13 11:12:55.487175-06 | f | idle in transaction | SELECT "version_rank","installed_rank","version","description","type","script","checksum","installed_on","installed_by","execution_time","success" FROM "public"."schema_version" ORDER BY "version_rank"
21095 | test_2015_04_13_110536 | 56825 | 16385 | postgres | | 127.0.0.1 | | 52438 | 2015-04-13 11:12:55.443687-06 | 2015-04-13 11:12:55.49024-06 | 2015-04-13 11:12:55.49024-06 | 2015-04-13 11:12:55.490241-06 | t | active | CREATE UNIQUE INDEX CONCURRENTLY person_restrict_duplicates_2_idx ON person(name, person_month, person_year)
(3 rows)
An example project that replicates this problem can be found in my github: chrisphelps/flyway-experiment
My suspicion is that the flyway query against schema version which is idle in transaction is preventing postgres from proceeding with the index creation.
How can I resolve the conflict so that postgres will proceed with the migration? Has anyone been able to apply this sort of migration to postgres via flyway?
In the meantime, there is a Resolver included in flyway which looks for some magic in the filename.
Just add the prefix 'NT' (for No-Transaction) to your migration file, i. e.
V01__usual_migration_1.sql
V02__another_migration.sql
NTV03__migration_that_does_not_run_in_transaction.sql
V04__classical_migration_4.sql
etc.
来源：https://stackoverflow.com/questions/29614429/flyway-migration-hangs-for-postgres-create-index-concurrently