Flyway migration hangs for postgres CREATE INDEX CONCURRENTLY

Question

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?

Answer 1

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.