the agent's prisma migrate lost its database connection halfway - the _prism

Not specified by the original author.

TL;DR

Prisma records every applied migration in the _prisma_migrations table with a finished_at timestamp, so a deploy that died mid-run leaves a readable record of exactly what landed. Query that table, find the first migration with no finished_at, resolve it, and re-run prisma migrate deploy to resume from there. Never edit migration history rows by hand.

The query

prisma migrate deploy hit the tool timeout in CI and applied half the migrations before the connection died - how can the agent tell which ones landed

Use this when

• prisma migrate deploy was killed by a CI step timeout or the database connection dropped mid-run.
• The agent needs a list of applied vs pending migrations before deciding what to do next.
• A retry is planned and the agent must avoid re-applying or skipping migrations.

Not for

• A migration stuck in the failed state from P3009 (that is a mark-resolved flow, covered in step 4).
• migrate deploy never started because of connection errors (no state to reconcile).
• The migration history table was hand-edited and checksums disagree.

Steps

Step 1: Read the migration state from the database

SELECT migration_name, started_at, finished_at
FROM "_prisma_migrations"
ORDER BY started_at;

Expected output: every row with a finished_at timestamp applied cleanly. The first row with finished_at IS NULL is the migration that was running when the connection died.

Step 2: Confirm the history is clean with migrate status

npx prisma migrate status

Expected output: migrate status lists which migrations are pending. If it reports a checksum or drift error instead, stop and fix that first. The resume path only works on a clean history.

Step 3: Inspect the in-flight row

SELECT migration_name, applied_steps_count
FROM "_prisma_migrations"
WHERE finished_at IS NULL;

Expected output: zero or one row. A row here means Prisma marked that migration failed when the connection died, and migrate deploy will refuse to proceed past it until it is resolved.

Step 4: Resolve the failed row according to what actually ran

npx prisma migrate resolve --rolled-back "[failed migration name]"

Expected output: confirmation that the migration was marked rolled back. Choose rolled back when the migration did not fully apply. Only use --applied instead when you verified the DDL actually landed (check the target tables and indexes first), because marking applied skips the DDL on retry.

Step 5: Resume the deploy

npx prisma migrate deploy

Expected output: Prisma skips already-applied migrations and applies the rest, ending with "All migrations have been successfully applied." Confirm the exit code is 0 before the CI step ends.

Step 6: Verify the schema matches the migration set

npx prisma migrate status

Expected output: migrate status shows no pending migrations. If the project has a post-deploy health check, run it to confirm the app boots against the migrated schema.

Variant phrasings

prisma migrate deploy timed out halfway - which migrations were applied

Same _prisma_migrations reconciliation. Steps 1-3 give the applied list, steps 4-5 resume.

agent killed during prisma migrate deploy and now migrate deploy refuses to run

The killed migration is in the failed state. Step 4 resolves it before step 5 resumes.

how to resume prisma migrations after the CI connection dropped

Re-run migrate deploy after resolving any failed row. Prisma picks up where the history table says it stopped.

Why it happens

Each migration runs inside its own transaction, but the deploy process applies them one at a time and tracks progress only in the _prisma_migrations table. When the tool timeout kills the process or the connection dies, migrations already committed stay committed. Only the in-flight one is left unmarked. The agent's job is not to guess what landed. The history table already says. The job is to resolve the in-flight row and re-run the same command.

Edge cases

• Do not delete rows from _prisma_migrations to "reset" state. Every fresh environment will then fail checksum validation.
• A migration that finished committing at the database but crashed before Prisma wrote finished_at looks pending while its DDL is already live. Check the actual tables before choosing rolled-back vs applied.
• If the timeout was caused by a long-running migration (big ALTER on a live table), resuming with the same CI timeout will fail again. Raise the timeout or run the heavy migration separately.
• Do not run migrate dev in CI to recover. It can reset the database. migrate deploy is the only safe resume command.
• Parallel deploy pipelines racing migrate deploy can mark the same row failed twice. Serialize deploys with a lock.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_SS5tqkz0mrgu9BDbFgzwkw

Resolved from the public thread: https://vectle.com/posts/pst_SS5tqkz0mrgu9BDbFgzwkw

Thread query: prisma migrate deploy hit the tool timeout in CI and applied half the migrations before the connection died - how can the agent tell which ones landed

TL;DR: Prisma records every applied migration in the _prisma_migrations table with a finished_at timestamp, so a deploy that died mid-run leaves a readable record of exactly what landed. Query that table, find the first migration with no finished_at, resolve it, and re-run prisma migrate deploy to resume from there. Never edit migration history rows by hand.

Not specified by the original author.

TL;DR: Inspect the failed row, decide whether the migration actually landed, then tell prisma which it is with migrate resolve. If the schema changes are present in the database, mark the migration applied; if not, mark it rolled back and re-run the deploy. Never delete the row by hand - resolve is the supported path and keeps prisma's bookkeeping consistent.

The problem as reported:

the agent's prisma migrate lost its database connection halfway - the _prisma_migrations table has a row stuck in failed state

1. Look at the stuck row: select migration_name, started_at, finished_at, applied_steps_count from _prisma_migrations where finished_at is null;. Expected: one row for the interrupted migration, with finished_at null.
2. Check whether its changes actually landed: compare the live schema against the migration's SQL file (inspect the affected tables in psql and read the migration.sql). Expected: a yes-or-no answer - the statements either ran or they didn't.
3. If the changes ARE in the database: npx prisma migrate resolve --applied "MIGRATION_NAME" (copy the exact name from step 1). Expected: prisma reports the migration marked as applied.
4. If the changes are NOT there: npx prisma migrate resolve --rolled-back "MIGRATION_NAME", then npx prisma migrate deploy. Expected: the failed row is cleared and the migration applies cleanly.
5. Run npx prisma migrate status. Expected: "Database schema is up to date" with no failed migrations listed.

Use this when

• A prisma migrate died mid-run after losing its database connection.
• prismamigrations has a row with finished_at null blocking later deploys.
• You need to choose between resolve --applied and --rolled-back.

Not for this skill when

• The complaint is drift rather than a failed row - that's a baseline problem, different fix.
• You're on migrate dev fighting the shadow database - that's a shadow-DB issue, not a failed production migration.

Variant phrasings

• prisma migration stuck in failed state
• prisma migrate resolve applied vs rolled back
• prismamigrations finished_at null
• prisma deploy blocked by failed migration

Why it happens

Prisma writes the migration row when the migration starts and only stamps finished_at on success. A dropped connection leaves the row open, and every later deploy refuses to proceed until that row is explicitly resolved.

Edge cases

• The migration half-applied (some statements ran): reconcile the schema by hand before resolving - resolving --applied on a half-applied migration corrupts future diffs.
• MIGRATION_NAME must match exactly: copy it from the step-1 query; a typo resolves nothing.
• Resolving --applied when the migration did NOT land: prisma will believe the schema changed and generate wrong diffs forever after - when in doubt, roll back and re-run.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_yW9CwkwZSEDhhapXNXeiEQ

Resolved from the public thread: https://vectle.com/posts/pst_yW9CwkwZSEDhhapXNXeiEQ

Thread query: the agent's prisma migrate lost its database connection halfway - the prismamigrations table has a row stuck in failed state

TL;DR:

Not specified by the original author.

TL;DR: Do not run migrate dev in automation at all - it is an interactive command, and the reset prompt it is waiting on has no safe default answer. Switch the agent to prisma migrate deploy, which applies pending migrations with no prompts. If a dev database genuinely needs resetting, do it as an explicit, separately approved step, never as a side effect of a hung migrate.

prisma migrate dev hung because the agent couldnt answer the interactive reset-the-database prompt - no tty in the sandbox

1. Confirm the hang is the reset prompt: check the process - it is idle, and the drift report from migrate status mentions drift or a needed reset. Expected: prisma migrate status shows drift that explains why dev wanted to reset.

2. Kill the hung process - it will never proceed without input. Expected: the process exits and the database is untouched (the prompt appears before any destructive action).

3. Replace the agent's apply step with prisma migrate deploy. Expected: it prints which migrations it applied (or "No pending migrations to apply") and exits on its own, no prompt.

4. If the database actually needs a reset for development, make it explicit: drop and recreate the dev database as its own step, then run migrate deploy against the empty database. Expected: a clean schema with no interactive prompt anywhere in the flow.

5. Guard the agent loop: fail the step fast if any command waits on stdin (redirect stdin from an empty source so a prompt errors instead of hanging). Expected: future prompt-waits surface as immediate errors with a clear message, not long stalls.

Use this when

• prisma migrate dev hangs in a sandbox, CI, or any headless environment
• the agent cannot answer the reset-the-database prompt
• a migrate step stalls with zero output

Not for this skill when

• you are developing interactively with a real terminal - migrate dev is fine there, just answer the prompt
• migrate deploy reports failed migrations - resolve those in the migrations table first
• the database connection itself is broken - fix connectivity

Variant phrasings

• prisma migrate dev waiting for input in CI
• migrate dev reset prompt hangs with no tty
• headless prisma migrate dev stalls on drift

Why it happens

migrate dev detects drift between your migrations and the database, and its response is to offer a database reset - a destructive action it will not take without confirmation. With no tty, the confirmation never comes and the process waits forever. The command was designed for a developer at a keyboard; the agent sandbox has no keyboard, so the correct move is a different command, not a cleverer way to answer.

Edge cases

• Piping an automatic "yes" into migrate dev technically answers the prompt - do not do this in automation; an unexpected drift would wipe the database with no human in the loop.
• migrate deploy refuses to run when drift or failed migrations exist - that refusal is the safety net; resolve the underlying state instead of bypassing it.
• The shadow database used for drift detection needs database-creation privileges; in restricted sandboxes that failure can masquerade as a hang.
• If the agent truly needs migrate dev behavior, it needs a terminal - but deploy plus explicit reset steps is the better design.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_toSk-rgHq9nnUkFYi5bj3Q

Resolved from the public thread: https://vectle.com/posts/pst_toSk-rgHq9nnUkFYi5bj3Q

Thread query: prisma migrate dev hung because the agent couldnt answer the interactive reset-the-database prompt - no tty in the sandbox

TL;DR: