Files
ComfyAssets-ComfyUI_PromptM…/database/library_move.py
T
Vito 9601837aa9 fix(system): never close another thread's library connection during a switch (#321)
* fix(system): never close another thread's library connection during a switch

Move library closed every thread's old connection from the mover thread,
including one whose owner was inside a statement waiting for the old
file's write lock. Closing a sqlite3 connection under a running
sqlite3_step is a use-after-free: Windows CI died with "access violation"
in record_prompt_use, and on Linux the writer got a MemoryError once its
busy timeout ran out.

Managed connections now count the calls their owner is inside.
Retiring one from another thread closes it at once only when idle;
otherwise it is interrupted (sqlite3_interrupt is thread-safe) and its
owner closes it as the call ends. A retired connection refuses new work
and never commits, so a write that waited for the lock is rolled back
and survive_library_switch runs it again on the new library. The mover
retires connections while it holds the locks and waits for the owners
to close them only after releasing them, before the old files are
renamed or a failed copy is removed. Cursors are closed before the
connection so Python 3.10/3.11 release the file handle too.

* test(tagging): wait for in-flight pages before reading the loaded range

The scroll-position test read the loaded count right after scrolling the
continuation out of view, while a listing page the continuation had
already requested could still be in flight. When it landed the count
grew (80 -> 120 in CI) and the stability poll failed. The test now waits
a frame for any scheduled load to start and then for every listing
request to finish before it reads the count.

* fix(system): make retiring a library connection race-free and cheap

Review round for the cross-thread close fix:

- cursor() now records its cursor under the lock _close_now copies the
  cursor set under, and refuses once the connection is retired; a cursor
  opened while the connection closed raised "Set changed size during
  iteration" out of retire() on Python 3.10-3.12. retire() never raises,
  retire_connections keeps going when one connection fails, and the mover
  never reports a completed switch as failed because retiring or awaiting
  old connections did.
- The restore's backup target is marked in use (ManagedConnection.using),
  and in_transaction and create_function are guarded.
- Iterating a cursor marks the connection in use once per fetchmany(128)
  chunk instead of once per row: a 1000-row scan costs 1.10x a plain
  cursor instead of 2.7x (3.14) / 3.8x (3.10).
- Document what an interrupt does not end, the statements a retired
  connection cannot hold back, close() from another thread returning
  before the file is closed, and the await timeout ending as old-in-use.
2026-10-24 20:39:08 -07:00

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"""Move library (#249 S6b): copy the node-folder library, verify it, switch.
``plan_move`` checks a ``utils.library_location`` location can move and
sizes the copy; ``move_library`` does it, in this order:
1. **Disk check** on the target's volume (the copy, the backups and
config.json, plus a margin). The source is never renamed across folders,
so another drive is simply a copy.
2. **Copy** with SQLite's backup API from a private connection holding one
read transaction: the per-table counts, the workflow documents' digest
and ``PRAGMA data_version`` describe exactly the copied snapshot. The copy
is a temp file in the target folder, made self-contained
(``journal_mode=DELETE``), fsynced and owner-only.
3. **Verify**: ``verify_database_file`` (integrity check, schema, every
workflow document decompressed against its hash, #315), the same row
count in every table and the same documents.
4. **Copy files**: every pooled safety backup and pre-migration backup,
checked by size and SHA-256 after the copy (their times are kept, so the
pool prunes in the same order).
5. **Publish** under the old database's write lock (``BEGIN IMMEDIATE``) and
the config.json lock: if any other connection wrote since the snapshot
(``data_version``), steps 2–4 run again (``attempts``, then
``library-busy``). Else config.json is copied (owner-only, checked), a
``pending`` marker is written, the temp files take their final names
(``os.replace`` inside the target folder), the marker turns ``moved``
and ``switch`` points the process at the new library while the old file
is still locked, so no write can land in it.
6. **Retire**: the old file's WAL is checkpointed and the old ``prompts.db``
and ``config.json`` are renamed ``*.moved-to-<folder>`` (never deleted;
the old backups stay where they are). A file still open elsewhere is left
in place and reported (``old-in-use``): the marker already makes a restart
use the new library.
Any failure before the marker says ``moved`` removes everything the move
wrote in the target folder and leaves the old library in use, untouched.
A crash at any point leaves either the old library in use (the marker is
absent or ``pending``; the next move replaces its own leftovers) or the new
one (``moved``). ``MoveFailed`` carries a code and a message without paths.
"""
import contextlib
import hashlib
import json
import os
import shutil
import sqlite3
import time
import types
import uuid
from pathlib import Path
from dataclasses import dataclass, field
from typing import Callable, Dict, List, Optional, Tuple
from .models import BUSY_TIMEOUT_SECONDS, PromptModel
try:
from ..utils import library_location as ll
from ..utils.logging_config import get_logger
except ImportError:
from utils import library_location as ll
from utils.logging_config import get_logger
logger = get_logger("prompt_manager.database.library_move")
TEMP_PREFIX = ".pm-move-"
MOVED_INFIX = ".moved-to-"
DISK_MARGIN_BYTES = 16 * 2**20
DEFAULT_ATTEMPTS = 3
_COPY_CHUNK = 4 * 2**20
# Backups that live beside the database and move with it.
BACKUP_INFIXES = (".backup_", ".pre-workflow-storage_")
MESSAGES = {
"not-movable": (
"This library is not in the node folder, so there is nothing to move."
),
"same-folder": "The new folder is the node folder itself.",
"target-invalid": "The new folder cannot hold the library.",
"target-has-library": (
"The new folder already holds a Prompt Manager library. Nothing was moved."
),
"target-conflict": (
"The new folder already holds files with the same names. Nothing was moved."
),
"insufficient-space": (
"There is not enough free space for the copy. Nothing was moved."
),
"copy-failed": "The copy could not be written or did not match. Nothing was moved.",
"verify-failed": "The copy did not pass verification. Nothing was moved.",
"library-busy": (
"Prompt Manager kept writing to the library while it was copied. "
"Nothing was moved; try again when no workflow is running."
),
"switch-failed": (
"Prompt Manager could not switch to the verified copy, so the copy was "
"removed. Nothing was moved."
),
}
class MoveFailed(Exception):
"""A move that did not happen (or did not finish), with a coded reason."""
def __init__(self, code: str, message: Optional[str] = None):
self.code = code
self.message = message or MESSAGES.get(code, "The library was not moved.")
super().__init__(self.message)
@dataclass(frozen=True)
class MovePlan:
location: "ll.LibraryLocation"
db_path: str
source_dir: str
target_dir: str
config_path: Optional[str]
backups: Tuple[str, ...]
db_bytes: int
files_bytes: int
@property
def required_bytes(self) -> int:
return self.db_bytes + self.files_bytes + DISK_MARGIN_BYTES
@property
def target_location(self) -> "ll.LibraryLocation":
"""Where the library is once moved (an explicit config.json stays)."""
source = self.location.target_source or ll.SOURCE_DEFAULT
config = (
self.location.config_path
if self.location.config_explicit
else os.path.join(self.target_dir, ll.CONFIG_NAME)
)
return ll.LibraryLocation(
source,
os.path.join(self.target_dir, ll.DATABASE_NAME),
config,
self.target_dir,
self.target_dir,
None,
source,
self.location.config_explicit,
)
@dataclass
class MoveResult:
location: "ll.LibraryLocation"
counts: Dict[str, int]
files: List[str]
renamed: List[str] = field(default_factory=list)
retire_problem: Optional[str] = None
def _size(path: str) -> int:
try:
return os.path.getsize(path)
except OSError:
return 0
def _free_bytes(path: str) -> int:
return shutil.disk_usage(path).free
def _existing_ancestor(path: str) -> str:
current = os.path.abspath(path)
while not os.path.isdir(current):
parent = os.path.dirname(current)
if parent == current:
break
current = parent
return current
def backup_names(db_path: str) -> Tuple[str, ...]:
"""The pooled and pre-migration backups beside ``db_path`` (names)."""
folder = os.path.dirname(os.path.abspath(db_path))
base = os.path.basename(db_path)
prefixes = tuple(base + infix for infix in BACKUP_INFIXES)
try:
names = os.listdir(folder)
except OSError:
return ()
return tuple(
sorted(
name
for name in names
if name.startswith(prefixes) and os.path.isfile(os.path.join(folder, name))
)
)
def plan_move(location) -> MovePlan:
"""Check ``location`` can move to its target; raises MoveFailed."""
if not location.movable:
raise MoveFailed("not-movable")
target = os.path.abspath(location.target_dir)
source_dir = os.path.dirname(os.path.abspath(location.db_path))
if ll.same_folder(target, source_dir) or os.path.normcase(
os.path.realpath(target)
) == os.path.normcase(os.path.realpath(source_dir)):
raise MoveFailed("same-folder")
if os.path.exists(target) and not os.path.isdir(target):
raise MoveFailed("target-invalid")
backups = backup_names(location.db_path)
# config.json moves with a node-folder library; one named by
# PROMPT_MANAGER_CONFIG_PATH is the user's and stays where it is.
config = None if location.config_explicit else location.config_path
config = config if config and os.path.isfile(config) else None
if ll.read_marker(target).get("state") != ll.MARKER_PENDING:
if os.path.exists(os.path.join(target, ll.DATABASE_NAME)):
raise MoveFailed("target-has-library")
names = [ll.CONFIG_NAME] if config else []
if any(os.path.exists(os.path.join(target, n)) for n in names + list(backups)):
raise MoveFailed("target-conflict")
db_bytes = _size(location.db_path) + _size(location.db_path + "-wal")
files_bytes = sum(_size(os.path.join(source_dir, n)) for n in backups)
files_bytes += _size(config) if config else 0
return MovePlan(
location,
os.path.abspath(location.db_path),
source_dir,
target,
config,
backups,
db_bytes,
files_bytes,
)
def space_problem(plan: MovePlan) -> Optional[Tuple[int, int]]:
"""``(required, free)`` when the target's volume is short, else None."""
free = _free_bytes(_existing_ancestor(plan.target_dir))
if free < plan.required_bytes:
return plan.required_bytes, free
return None
# ── copy and verify ───────────────────────────────────────────────────
def _tables(conn) -> List[str]:
return [
row[0]
for row in conn.execute(
"SELECT name FROM sqlite_master WHERE type='table' "
"AND name NOT LIKE 'sqlite_%' ORDER BY name"
)
]
def _describe(conn) -> Tuple[Dict[str, int], str]:
"""Row counts per table and a digest of the workflow documents."""
counts = {}
for table in _tables(conn):
# A name read from sqlite_master, quoted as an identifier.
quoted = '"' + table.replace('"', '""') + '"'
sql = f"SELECT COUNT(*) FROM {quoted}" # nosec B608
counts[table] = conn.execute(sql).fetchone()[0]
digest = hashlib.sha256()
if "workflow_documents" in counts:
for row in conn.execute(
"SELECT id, sha256, byte_length FROM workflow_documents ORDER BY id"
):
digest.update(repr((row[0], bytes(row[1]), row[2])).encode())
return counts, digest.hexdigest()
def _fsync_file(path: str) -> None:
with open(path, "rb+") as handle:
os.fsync(handle.fileno())
def _fsync_dir(path: str) -> None:
if os.name != "posix":
return
fd = os.open(path, os.O_RDONLY)
try:
os.fsync(fd)
finally:
os.close(fd)
def _private(path: str) -> None:
if os.name == "posix":
os.chmod(path, 0o600)
def _copy_snapshot(source: sqlite3.Connection, temp: str):
"""Back up ``source``'s current snapshot to ``temp``; return what it holds."""
source.execute("BEGIN")
try:
version = source.execute("PRAGMA data_version").fetchone()[0]
counts, documents = _describe(source)
destination = sqlite3.connect(temp)
try:
source.backup(destination)
finally:
destination.close()
finally:
source.execute("COMMIT")
with contextlib.closing(sqlite3.connect(temp)) as conn:
conn.execute("PRAGMA journal_mode=DELETE").fetchone()
_fsync_file(temp)
_private(temp)
return version, counts, documents
def _verify_copy(temp: str, counts, documents) -> None:
ok, reason = PromptModel.verify_database_file(temp)
if not ok:
logger.error(f"Library move: the copy did not verify: {reason}")
detail = reason if reason.startswith("Workflow document") else None
raise MoveFailed(
"verify-failed",
f"{MESSAGES['verify-failed']} {detail}" if detail else None,
)
uri = Path(os.path.abspath(temp)).as_uri() + "?mode=ro"
try:
with contextlib.closing(sqlite3.connect(uri, uri=True)) as conn:
copied = _describe(conn)
except sqlite3.Error as error:
logger.error(f"Library move: the copy could not be read: {error}")
raise MoveFailed("verify-failed") from error
if copied != (counts, documents):
logger.error("Library move: the copy's rows or documents differ")
raise MoveFailed("verify-failed")
def _hash_copy(source: str, destination: str) -> Tuple[int, str]:
"""Copy ``source`` to ``destination`` (fsynced, owner-only, times kept)."""
digest = hashlib.sha256()
size = 0
with open(source, "rb") as reader, open(destination, "wb") as writer:
while True:
chunk = reader.read(_COPY_CHUNK)
if not chunk:
break
digest.update(chunk)
size += len(chunk)
writer.write(chunk)
writer.flush()
os.fsync(writer.fileno())
stat = os.stat(source)
os.utime(destination, ns=(stat.st_atime_ns, stat.st_mtime_ns))
_private(destination)
return size, digest.hexdigest()
def _file_digest(path: str) -> Tuple[int, str]:
digest = hashlib.sha256()
size = 0
with open(path, "rb") as reader:
while True:
chunk = reader.read(_COPY_CHUNK)
if not chunk:
return size, digest.hexdigest()
digest.update(chunk)
size += len(chunk)
def _check_copies(copies) -> None:
for source, temp, expected in copies:
if _file_digest(temp) != expected or _file_digest(source) != expected:
logger.error(
f"Library move: {os.path.basename(source)} did not copy unchanged"
)
raise MoveFailed("copy-failed")
def write_marker(
directory: str, state: str, source_db: str, source_config: Optional[str] = None
) -> str:
"""Atomically write the move marker; return its path.
``from`` and ``config_from`` name the old files, so a restart after a
crash between the switch and the rename can finish the rename.
"""
path = os.path.join(directory, ll.MARKER_NAME)
temp = os.path.join(directory, f"{TEMP_PREFIX}{uuid.uuid4().hex}.marker")
payload = json.dumps(
{
"version": 1,
"state": state,
"from": source_db,
"config_from": source_config,
"updated_at": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
},
indent=2,
).encode("utf-8")
fd = os.open(temp, os.O_WRONLY | os.O_CREAT | os.O_EXCL, 0o600)
try:
with os.fdopen(fd, "wb") as handle:
handle.write(payload)
handle.flush()
os.fsync(handle.fileno())
_private(temp)
os.replace(temp, path)
except BaseException:
_remove(temp)
raise
_fsync_dir(directory)
return path
def _remove(*paths) -> None:
for path in paths:
try:
if path and os.path.lexists(path):
os.remove(path)
except OSError:
logger.warning(f"Library move: could not remove {os.path.basename(path)}")
def sweep_move_temps(directory: str) -> List[str]:
"""Remove the temp files an interrupted move left in ``directory``."""
removed = []
try:
names = os.listdir(directory)
except OSError:
return removed
for name in names:
if name.startswith(TEMP_PREFIX):
_remove(os.path.join(directory, name))
removed.append(name)
return removed
# ── the move ─────────────────────────────────────────────────────────
def _noop(*_args, **_kwargs):
return None
def switch_process(old_db: str, location, detached: list) -> None:
"""Point this process at ``location``: resolver, every model, observers.
Adds the old file's connections, detached and still open, to
``detached`` as soon as they are detached, so the mover retires them
(``PromptModel.retire_detached``) whether or not the rest succeeds.
"""
from .execution_history import rekey_history_restore
from .review_changes import rekey_review_changes
ll.switch_to(location)
detached.extend(PromptModel.repoint_instances(old_db, location.db_path))
rekey_review_changes(old_db, location.db_path)
rekey_history_restore(old_db, location.db_path)
def unswitch_process(old_db: str, new_db: str) -> list:
"""Undo ``switch_process`` (any part of it); returns detached connections."""
from .execution_history import rekey_history_restore
from .review_changes import rekey_review_changes
ll.clear_override()
detached = PromptModel.repoint_instances(new_db, old_db)
rekey_review_changes(new_db, old_db)
rekey_history_restore(new_db, old_db)
return detached
class _Move:
def __init__(self, plan, *, switch, config_lock, progress, checkpoint):
self.plan = plan
self.switch = switch
self.config_lock = config_lock
self.progress = progress
self.checkpoint = checkpoint
self.created_dir = False
self.temps: List[str] = []
self.published: List[str] = []
self.marker: Optional[str] = None
self.moved = False
# Retired connections still in use; awaited once the locks are free.
self.retiring: list = []
def temp(self, suffix: str) -> str:
path = os.path.join(
self.plan.target_dir, f"{TEMP_PREFIX}{uuid.uuid4().hex}{suffix}"
)
self.temps.append(path)
return path
def prepare_target(self) -> None:
target = self.plan.target_dir
self.created_dir = not os.path.isdir(target)
ll.ensure_private_dir(target)
sweep_move_temps(target)
if ll.read_marker(target).get("state") == ll.MARKER_PENDING:
# An earlier move stopped before it switched: its files are ours.
for name in (ll.DATABASE_NAME, ll.CONFIG_NAME) + self.plan.backups:
_remove(os.path.join(target, name))
for suffix in ("-wal", "-shm", "-journal"):
_remove(os.path.join(target, ll.DATABASE_NAME + suffix))
def copy_round(self, source):
"""Steps 2–4 once: the verified temp copies and the snapshot version."""
self.progress("Copying the database")
temp_db = self.temp(".db")
version, counts, documents = _copy_snapshot(source, temp_db)
self.checkpoint("copied")
self.progress("Verifying the copy")
_verify_copy(temp_db, counts, documents)
self.checkpoint("verified")
copies = []
for name in self.plan.backups:
src = os.path.join(self.plan.source_dir, name)
temp = self.temp(".bak")
try:
expected = _hash_copy(src, temp)
except OSError as error:
logger.error(f"Library move: copying {name} failed: {error}")
raise MoveFailed("copy-failed") from error
copies.append((src, temp, expected, name))
if copies:
self.progress(f"Copied {len(copies)} backup file(s)")
self.checkpoint("files")
_check_copies([(s, t, e) for s, t, e, _ in copies])
return version, counts, temp_db, copies
def discard_round(self, temp_db, copies) -> None:
_remove(temp_db, *[temp for _s, temp, _e, _n in copies])
def publish(self, temp_db, copies) -> List[str]:
"""Under the locks: config.json, marker, final names, marker moved."""
target = self.plan.target_dir
files = []
if self.plan.config_path:
temp = self.temp(".config")
try:
expected = _hash_copy(self.plan.config_path, temp)
except OSError as error:
raise MoveFailed("copy-failed") from error
_check_copies([(self.plan.config_path, temp, expected)])
copies = copies + [(self.plan.config_path, temp, expected, ll.CONFIG_NAME)]
self.marker = write_marker(
target, ll.MARKER_PENDING, self.plan.db_path, self.plan.config_path
)
self.checkpoint("pending")
for _src, temp, _expected, name in copies:
final = os.path.join(target, name)
os.replace(temp, final)
self.published.append(final)
files.append(name)
final_db = os.path.join(target, ll.DATABASE_NAME)
os.replace(temp_db, final_db)
self.published.append(final_db)
files.append(ll.DATABASE_NAME)
_fsync_dir(target)
self.checkpoint("published")
write_marker(target, ll.MARKER_MOVED, self.plan.db_path, self.plan.config_path)
self.moved = True
self.checkpoint("marked")
return files
def cleanup(self) -> None:
if self.moved:
return
_remove(*self.temps, *self.published, self.marker)
if self.created_dir:
try:
os.rmdir(self.plan.target_dir)
except OSError:
pass
def _unique(path: str) -> str:
candidate, number = path, 1
while os.path.lexists(candidate):
candidate = f"{path}_{number}"
number += 1
return candidate
def retire_old_files(plan: MovePlan) -> Tuple[List[str], Optional[str]]:
"""Rename the old database and config.json; ``(renamed, problem code)``.
Every connection to the old file must be closed. The WAL is checkpointed
first; when it cannot be emptied (another process still has the file
open) nothing is renamed (``old-in-use``).
"""
old = plan.db_path
folder = os.path.basename(os.path.normpath(plan.target_dir))
try:
with contextlib.closing(sqlite3.connect(old, timeout=1)) as conn:
busy = conn.execute("PRAGMA wal_checkpoint(TRUNCATE)").fetchone()[0]
except sqlite3.Error as error:
logger.warning(
f"Library move: the old database could not be checkpointed: {error}"
)
return [], "old-in-use"
if busy or _size(old + "-wal") > 0:
return [], "old-in-use"
renamed = []
try:
for path in (old, plan.config_path):
if not path or not os.path.isfile(path):
continue
new_name = _unique(path + MOVED_INFIX + folder)
os.rename(path, new_name)
renamed.append(os.path.basename(new_name))
for suffix in ("-wal", "-shm"):
if os.path.isfile(old + suffix) and _size(old + suffix) == 0:
os.remove(old + suffix)
except OSError as error:
logger.warning(f"Library move: the old files could not be renamed: {error}")
return renamed, "old-locked"
return renamed, None
def finish_interrupted_move(location) -> List[str]:
"""Rename old files a crash left between the switch and the rename.
The marker of the folder in use says ``moved`` and names the old files;
an old ``prompts.db`` (and config.json) still there under its own name is
renamed ``*.moved-to-<folder>`` now, never deleted. Returns the new
names (nothing when there is nothing to finish or the file is in use).
"""
if location.source not in (ll.SOURCE_DEFAULT, ll.SOURCE_ENVIRONMENT):
return []
marker = ll.read_marker(location.data_dir)
old = marker.get("from")
if marker.get("state") != ll.MARKER_MOVED or not isinstance(old, str):
return []
if not os.path.isfile(old) or os.path.basename(old) != ll.DATABASE_NAME:
return []
if ll.same_folder(os.path.dirname(old), location.data_dir):
return []
config = marker.get("config_from")
if not (
isinstance(config, str)
and os.path.basename(config) == ll.CONFIG_NAME
and os.path.isfile(config)
and os.path.normcase(os.path.abspath(config))
!= os.path.normcase(os.path.abspath(location.config_path))
):
config = None
pending = types.SimpleNamespace(
db_path=old, config_path=config, target_dir=location.data_dir
)
renamed, problem = retire_old_files(pending)
if problem:
logger.warning(f"Library move: the old files are still in use ({problem})")
elif renamed:
logger.info(f"Library move finished: renamed {', '.join(renamed)}")
return renamed
def move_library(
plan: MovePlan,
*,
switch: Callable = switch_process,
unswitch: Callable = unswitch_process,
after_switch: Callable = _noop,
config_lock=None,
progress: Callable[[str], None] = _noop,
checkpoint: Callable[[str], None] = _noop,
attempts: int = DEFAULT_ATTEMPTS,
) -> MoveResult:
"""Move the library as planned (blocking; see the module docstring).
``switch(old_db, location, detached)`` points the process at the copy
and adds the old connections it detached to ``detached``; if it raises,
``unswitch(old_db, new_db)`` undoes it while both files are still
locked, every detached connection is closed, the copy is removed and
the move fails (``switch-failed``). ``after_switch()`` runs
once the switch is final; it is best effort (logged, never fails the move).
"""
short = space_problem(plan)
if short is not None:
raise MoveFailed("insufficient-space")
lock = config_lock if config_lock is not None else contextlib.nullcontext()
move = _Move(
plan,
switch=switch,
config_lock=lock,
progress=progress,
checkpoint=checkpoint,
)
move.unswitch = unswitch
location = plan.target_location
try:
move.prepare_target()
files, counts = _copy_and_switch(move, location, attempts)
except Exception:
move.cleanup()
raise
try:
after_switch()
except Exception:
logger.exception("Library move: a follow-up after the switch failed")
from .execution_history import notify_history_restore
notify_history_restore(location.db_path)
progress("Renaming the old files")
renamed, problem = retire_old_files(plan)
checkpoint("retired")
return MoveResult(location, counts, files, renamed, problem)
def _switch_guarded(move: _Move, location) -> list:
"""Switch while the copy is locked too; undo it all if any part fails.
The copy's write lock keeps every repointed thread from writing to it
until the switch is whole, so undoing a partial switch loses nothing.
Returns the old file's detached connections (still open). On failure
every detached connection is retired; those still in use are added to
``move.retiring`` for the caller to await once the locks are released.
"""
plan = move.plan
guard = sqlite3.connect(
location.db_path, timeout=BUSY_TIMEOUT_SECONDS, isolation_level=None
)
try:
guard.execute("BEGIN IMMEDIATE")
detached: list = []
try:
move.switch(plan.db_path, location, detached)
except Exception as error:
logger.exception("Library move: switching failed; undoing it")
move.moved = False # the copy and its marker are removed
# Retire, never wait, here: a connection still in use may be
# waiting on the very locks this thread holds.
try:
undone = move.unswitch(plan.db_path, location.db_path)
except Exception:
logger.exception("Library move: undoing the switch failed")
else:
_retire(move, undone)
# The old file's connections a partial switch detached: the
# models reopen it on next use, so close them now, not at GC.
_retire(move, detached)
raise MoveFailed("switch-failed") from error
move.checkpoint("switched")
return detached
finally:
if guard.in_transaction:
guard.execute("ROLLBACK")
guard.close()
def _copy_and_switch(move: _Move, location, attempts: int):
"""Copy, then switch under both locks; retired connections are awaited.
A connection that was inside a statement when it was retired is closed
by its own thread once the statement ends, which may need the locks
released first; the old files are renamed (and a failed copy removed)
only after that, since Windows refuses to rename or delete an open file.
"""
try:
return _copy_and_switch_locked(move, location, attempts)
finally:
try:
PromptModel.await_detached(move.retiring, logger)
except Exception:
logger.exception("Library move: waiting for old connections failed")
def _retire(move: _Move, connections: list) -> None:
"""Retire ``connections``, adding those still in use to ``move.retiring``.
Never raises: a switch that completed must not be reported as failed
because one of the old connections could not be retired (logged; the
rename then reports the old files as still in use).
"""
try:
move.retiring.extend(PromptModel.retire_detached(connections, logger))
except Exception:
logger.exception("Library move: retiring the old connections failed")
def _copy_and_switch_locked(move: _Move, location, attempts: int):
plan = move.plan
for attempt in range(1, attempts + 1):
source = sqlite3.connect(
plan.db_path, timeout=BUSY_TIMEOUT_SECONDS, isolation_level=None
)
try:
source.execute(f"PRAGMA busy_timeout = {BUSY_TIMEOUT_SECONDS * 1000}")
version, counts, temp_db, copies = move.copy_round(source)
source.execute("BEGIN IMMEDIATE")
try:
if source.execute("PRAGMA data_version").fetchone()[0] != version:
move.progress("The library changed during the copy; copying again")
move.discard_round(temp_db, copies)
continue
move.checkpoint("locked")
with move.config_lock:
files = move.publish(temp_db, copies)
detached = _switch_guarded(move, location)
# Still holding the old file's lock: a write that was waiting
# on it is interrupted and cannot commit, so it fails (and
# runs again on the new library) instead of landing in the
# old file. Its own thread closes the connection.
_retire(move, detached)
finally:
if source.in_transaction:
source.execute("ROLLBACK")
return files, counts
finally:
source.close()
raise MoveFailed("library-busy")