Incident brief
Invalid input syntax
A string literal was cast to a type whose input function couldn't parse it. PostgreSQL rejected the value outright rather than guessing at a conversion.
In 10 seconds
- What
- Invalid input syntax
- What triggers it
- Cast a string literal to a type whose input function can't parse it (e.g. a non-numeric string to integer).
- The fix
- Fix the literal so it matches the target type's actual input format.
- Proof
- Reproduced on PostgreSQL 16.14 → Casting a non-numeric string to integer was rejected with SQLSTATE 22P02, naming the exact invalid value. The session was unaffected afterward.
The fix
What to do right now
The immediate, application-level response to this error.
- Fix the literal so it matches the target type's actual input format.
- For boolean specifically, only a documented set of strings — and their unique prefixes — are accepted; see the premium test.
- Don't rely on NULLIF to guard this generally — see the counterexample for why it only catches one specific value.
SELECT '42'::integer;Diagnose
See it live on the server
Run these against the affected instance to confirm the diagnosis before you act.
Standard triage — not specific to this error
These are canonical PostgreSQL system-catalog queries, shown as SQL to run. No sample output is attached because this is general triage, not a captured lab transcript.This SQLSTATE does not have an error-specific live snapshot yet. These are the canonical system-catalog queries you run against the affected server to see the problem in real time — standard triage, not a reproduced transcript.
What is running right now
Active backends, how long each has been running, and what it is waiting on.
SELECT pid,
state,
wait_event_type,
wait_event,
now() - query_start AS running_for,
left(query, 80) AS query
FROM pg_stat_activity
WHERE state <> 'idle'
AND pid <> pg_backend_pid()
ORDER BY running_for DESC NULLS LAST;Who is blocking whom
Turn raw blocking PIDs into the actual queries on both sides of the wait.
SELECT blocked.pid AS blocked_pid,
blocked.query AS blocked_query,
blocking.pid AS blocking_pid,
blocking.query AS blocking_query
FROM pg_stat_activity AS blocked
JOIN LATERAL unnest(pg_blocking_pids(blocked.pid)) AS b(pid) ON true
JOIN pg_stat_activity AS blocking ON blocking.pid = b.pid
WHERE cardinality(pg_blocking_pids(blocked.pid)) > 0;Locks that are still waiting
Every lock a backend has requested but not yet been granted.
SELECT l.pid,
l.locktype,
l.mode,
l.granted,
COALESCE(c.relname, l.transactionid::text) AS object
FROM pg_locks l
LEFT JOIN pg_class c ON c.oid = l.relation
WHERE NOT l.granted
ORDER BY l.pid;Why it happens
What PostgreSQL is telling you
The mechanism behind the error, grounded in the official manual — not paraphrased.
PostgreSQL 16 Documentation — §8.6 Boolean Type
Unique prefixes of these strings are also accepted, for example t or n. Leading or trailing whitespace is ignored, and case does not matter.Read the full section on postgresql.org →
The invalid cast
integer's input function only accepts strings that parse as whole numbers. 'not_a_number' doesn't, so PostgreSQL rejected the value outright instead of guessing.Confirming the session still works
The failed cast didn't affect the session — the next statement ran normally.Reproduce & verify
A real, single-session PostgreSQL reproduction
A literal transcript of SQL run against a live PostgreSQL instance in an isolated lab — the commands below are exactly what was executed.
- 1Cast a string literal to a type whose input function can't parse it (e.g. a non-numeric string to integer).
- 2PostgreSQL's type input function rejects the value.
- 3SQLSTATE 22P02 is reported, naming the exact string and target type.
One client: cast an invalid string literal to integer.
-- No table needed: the failure happens purely at the type-input-function stage.
SELECT 'no schema required' AS setup_note;SELECT 'not_a_number'::integer;SELECT 1 AS session_still_alive;What PostgreSQL actually returned
setup_note
--------------------
no schema required
(1 row)ERROR: invalid input syntax for type integer: "not_a_number"
LINE 1: SELECT 'not_a_number'::integer;
^ session_still_alive
----------------------
1
(1 row)The manual documents exactly which string representations boolean's input function accepts, including unique prefixes, whitespace, and case handling. This was tested directly, alongside a string that matches none of them.
Cast single-letter prefixes ('t', 'n') and a padded, mixed-case word ('true') to boolean, then cast a string that isn't a documented representation or prefix.
Without this
Above: 'not_a_number'::integer has no valid parse and is rejected.
With this, tested
Below: boolean's documented prefixes and padded/mixed-case input are all accepted; a string matching none of them is still rejected.
What Pro unlocks here
- The exact prevention SQL — copy-paste ready
- Raw psql output captured from the Docker lab
- A senior-DBA action list to take it further
- Live monitoring queries to catch it in production
- The deeper audit: fix-that-fails counterexample, GUC before/after, server-log evidence
Related & next steps
Follow the thread
Everything this error touches — jump straight to the sibling error, term, runbook, or parameter.
Verification
- Last verified
- 2026-07-15 (Docker lab, PostgreSQL 16.14)
- Reviewed by
- Verified against PostgreSQL 16.14 in an isolated lab environment
- Audit status
- reviewed