Why does this PostgreSQL transaction give “WARNING: there is no transaction in progress”

Question

I am running the transaction queries in code like this (simplified):

try {
    runQuery("begin");
    runQuery("some query ...");
    runQuery("some other query ...");
    runQuery("some more query ...");
    runQuery("some extra query ...");
    runQuery("commit");
} catch (e){
    runQuery("rollback");
}

Here is the list of statements from the postgres log file.
Notice that first begin / commit works fine and the second commit gives the error mentioned in the subject:

2015-02-18 20:19:17 UTC [6459-7] vdsr@sails LOG:  statement: begin
2015-02-18 20:19:17 UTC [6459-8] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "groups" ("name", "parentGroupRef", "isCompany", "companyRef", "createdAt", "updatedAt") values ($1, $2, $3, $4, $5, $6) RETURNING *
2015-02-18 20:19:17 UTC [6459-9] vdsr@sails DETAIL:  parameters: $1 = 'testclient', $2 = '5', $3 = 't', $4 = '1', $5 = '2015-02-18 20:19:17+00', $6 = '2015-02-18 20:19:17+00'
2015-02-18 20:19:17 UTC [6459-10] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "users" ("firstName", "lastName", "email", "companyRef", "isMainUser", "password", "middleName", "createdAt", "updatedAt") values ($1, $2, $3, $4, $5, $6, $7, $8, $9) RETURNING *
2015-02-18 20:19:17 UTC [6459-11] vdsr@sails DETAIL:  parameters: $1 = 'aa', $2 = 'bb', $3 = 'aa@bb.com', $4 = '18', $5 = 't', $6 = '06a8ec164adcc7db4edfb6ca20c07b20', $7 = '', $8 = '2015-02-18 20:19:17+00', $9 = '2015-02-18 20:19:17+00'
2015-02-18 20:19:17 UTC [6459-12] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "roles" ("name", "companyRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:19:17 UTC [6459-13] vdsr@sails DETAIL:  parameters: $1 = 'Master', $2 = '18', $3 = '2015-02-18 20:19:17+00', $4 = '2015-02-18 20:19:17+00'
2015-02-18 20:19:17 UTC [6459-14] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "userroles" ("roleRef", "userRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:19:17 UTC [6459-15] vdsr@sails DETAIL:  parameters: $1 = '11', $2 = '13', $3 = '2015-02-18 20:19:17+00', $4 = '2015-02-18 20:19:17+00'
2015-02-18 20:19:17 UTC [6459-16] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "rolepermissions" ("roleRef", "permissionRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:19:17 UTC [6459-17] vdsr@sails DETAIL:  parameters: $1 = '11', $2 = '24', $3 = '2015-02-18 20:19:17+00', $4 = '2015-02-18 20:19:17+00'
2015-02-18 20:19:17 UTC [6459-18] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "rolepermissions" ("roleRef", "permissionRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:19:17 UTC [6459-19] vdsr@sails DETAIL:  parameters: $1 = '11', $2 = '22', $3 = '2015-02-18 20:19:17+00', $4 = '2015-02-18 20:19:17+00'
2015-02-18 20:19:17 UTC [6459-20] vdsr@sails LOG:  execute <unnamed>: SELECT "groups"."name", "groups"."notes", "groups"."parentGroupRef", "groups"."isCompany", "groups"."hierPos", "groups"."companyRef", "groups"."id", "groups"."createdAt", "groups"."updatedAt" FROM "groups" AS "groups"  WHERE "groups"."companyRef" = $1 
2015-02-18 20:19:17 UTC [6459-21] vdsr@sails DETAIL:  parameters: $1 = '1'
2015-02-18 20:19:17 UTC [6461-1] vdsr@sails LOG:  statement:  update groups set "hierPos" = case id when 2 then '1' when 3 then '2' when 4 then '3' when 5 then '4' when 6 then '4.1' when 10 then '4.1.1' when 18 then '4.2' when 13 then '5' when 17 then '6' else "hierPos" end  where id in (2,3,4,5,6,10,18,13,17) 
2015-02-18 20:19:17 UTC [6459-22] vdsr@sails LOG:  statement: commit
2015-02-18 20:26:08 UTC [6477-1] vdsr@sails LOG:  execute <unnamed>: SELECT "users"."firstName", "users"."middleName", "users"."lastName", "users"."email", "users"."password", "users"."resetKey", "users"."resetKeyGeneratedAt", "users"."isMainUser", "users"."companyRef", "users"."id", "users"."createdAt", "users"."updatedAt" FROM "users" AS "users"  WHERE "users"."id" = $1  LIMIT 1
2015-02-18 20:26:08 UTC [6477-2] vdsr@sails DETAIL:  parameters: $1 = '8'
2015-02-18 20:26:08 UTC [6477-3] vdsr@sails LOG:  execute <unnamed>: select p.name from permissions p  inner join rolepermissions rp on rp."permissionRef" = p.id   inner join roles r on r.id = rp."roleRef"  inner join userroles ur on ur."roleRef" = r.id  where ur."userRef" = $1
2015-02-18 20:26:08 UTC [6477-4] vdsr@sails DETAIL:  parameters: $1 = '8'
2015-02-18 20:26:08 UTC [6477-5] vdsr@sails LOG:  statement: begin
2015-02-18 20:26:08 UTC [6477-6] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "groups" ("name", "isCompany", "parentGroupRef", "companyRef", "createdAt", "updatedAt") values ($1, $2, $3, $4, $5, $6) RETURNING *
2015-02-18 20:26:08 UTC [6477-7] vdsr@sails DETAIL:  parameters: $1 = 'ddffdfd', $2 = 't', $3 = '1', $4 = '1', $5 = '2015-02-18 20:26:08+00', $6 = '2015-02-18 20:26:08+00'
2015-02-18 20:26:08 UTC [6477-8] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "users" ("firstName", "lastName", "email", "companyRef", "isMainUser", "password", "middleName", "createdAt", "updatedAt") values ($1, $2, $3, $4, $5, $6, $7, $8, $9) RETURNING *
2015-02-18 20:26:08 UTC [6477-9] vdsr@sails DETAIL:  parameters: $1 = 'fdfd', $2 = 'fdfd', $3 = 'fdf@df.com', $4 = '19', $5 = 't', $6 = '7b9e87b1795e4d96bf9fbb898fa669fe', $7 = '', $8 = '2015-02-18 20:26:08+00', $9 = '2015-02-18 20:26:08+00'
2015-02-18 20:26:08 UTC [6477-10] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "roles" ("name", "companyRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:26:08 UTC [6477-11] vdsr@sails DETAIL:  parameters: $1 = 'Master', $2 = '19', $3 = '2015-02-18 20:26:08+00', $4 = '2015-02-18 20:26:08+00'
2015-02-18 20:26:08 UTC [6477-12] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "userroles" ("roleRef", "userRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:26:08 UTC [6477-13] vdsr@sails DETAIL:  parameters: $1 = '12', $2 = '14', $3 = '2015-02-18 20:26:08+00', $4 = '2015-02-18 20:26:08+00'
2015-02-18 20:26:08 UTC [6477-14] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "rolepermissions" ("roleRef", "permissionRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:26:08 UTC [6477-15] vdsr@sails DETAIL:  parameters: $1 = '12', $2 = '24', $3 = '2015-02-18 20:26:08+00', $4 = '2015-02-18 20:26:08+00'
2015-02-18 20:26:08 UTC [6477-16] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "rolepermissions" ("roleRef", "permissionRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:26:08 UTC [6477-17] vdsr@sails DETAIL:  parameters: $1 = '12', $2 = '22', $3 = '2015-02-18 20:26:08+00', $4 = '2015-02-18 20:26:08+00'
2015-02-18 20:26:08 UTC [6477-18] vdsr@sails LOG:  execute <unnamed>: INSERT INTO "rolepermissions" ("roleRef", "permissionRef", "createdAt", "updatedAt") values ($1, $2, $3, $4) RETURNING *
2015-02-18 20:26:08 UTC [6477-19] vdsr@sails DETAIL:  parameters: $1 = '12', $2 = '23', $3 = '2015-02-18 20:26:08+00', $4 = '2015-02-18 20:26:08+00'
2015-02-18 20:26:08 UTC [6477-20] vdsr@sails LOG:  execute <unnamed>: SELECT "groups"."name", "groups"."notes", "groups"."parentGroupRef", "groups"."isCompany", "groups"."hierPos", "groups"."companyRef", "groups"."id", "groups"."createdAt", "groups"."updatedAt" FROM "groups" AS "groups"  WHERE "groups"."companyRef" = $1 
2015-02-18 20:26:08 UTC [6477-21] vdsr@sails DETAIL:  parameters: $1 = '1'
2015-02-18 20:26:08 UTC [6478-1] vdsr@sails LOG:  statement:  update groups set "hierPos" = case id when 2 then '1' when 3 then '2' when 4 then '3' when 5 then '4' when 6 then '4.1' when 10 then '4.1.1' when 18 then '4.2' when 13 then '5' when 17 then '6' when 19 then '7' else "hierPos" end  where id in (2,3,4,5,6,10,18,13,17,19) 
2015-02-18 20:26:08 UTC [6479-1] vdsr@sails LOG:  statement: commit
2015-02-18 20:26:08 UTC [6479-2] vdsr@sails WARNING:  there is no transaction in progress

Answer 1

This seems to be a misunderstanding. Consider my bold emphasis:

[6459-7] vdsr@sails LOG: statement: begin
[6459-8] vdsr@sails LOG: execute : INSERT INTO "groups" ("name", "parentGroupRef", "isCompany", "companyRef", "createdAt", "updatedAt") values ($1, $2, $3, $4, $5, $6) RETURNING *
...
[6459-22] vdsr@sails LOG: statement: commit
...
[6477-5] vdsr@sails LOG: statement: begin
[6477-6] vdsr@sails LOG: execute : INSERT INTO "groups" ("name", "isCompany", "parentGroupRef", "companyRef", "createdAt", "updatedAt") values ($1, $2, $3, $4, $5, $6) RETURNING *
...
[6479-1] vdsr@sails LOG: statement: commit
[6479-2] vdsr@sails WARNING: there is no transaction in progress

The WARNING obviously belongs to a different concurrent transaction, which did not start an explicit transaction. The commit is misplaced there, since it's operating in autocommit mode.

If you keep reading your log, you will probably find an entry for the commit further down:

[6477-??] vdsr@sails LOG: statement: commit

Debug

If you find neither that nor a rollback entry nor an error, I would check for problems in your app leaving uncommitted zombi transactions, which would be a bad thing.

Start the investigation by checking the system view pg_stat_activity while connected to your database:

SELECT *
FROM   pg_stat_activity
WHERE  datname = current_database()  -- only current database
AND    pid <> pg_backend_pid()       -- except your current session
AND    state LIKE 'idle%';

The state value idle is not necessarily suspicious - just a session that's waiting for input.
But idle in transaction and idle in transaction (aborted) are.

More in the manual here or these related answers:

• How to drop a PostgreSQL database if there are active connections to it?
• Is there a timeout for idle PostgreSQL connections?

Answer 2

This is caused by the sails-postgresql node module I am using. It is causing a new session to be created in the middle of my transaction queries and so the commit query was being issued by a different session. That was causing the warning.