roryqi commented on code in PR #13386: URL: https://github.com/apache/gravitino/pull/13386#discussion_r4219109887
########## design-docs/table-maintenance-service-design.md: ########## @@ -0,0 +1,663 @@ +<!-- + Licensed to the Apache Software Foundation (ASF) under one + or more contributor license agreements. See the NOTICE file + distributed with this work for additional information + regarding copyright ownership. The ASF licenses this file + to you under the Apache License, Version 2.0 (the + "License"); you may not use this file except in compliance + with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, + software distributed under the License is distributed on an + "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + KIND, either express or implied. See the License for the + specific language governing permissions and limitations + under the License. +--> + +# Design of Table Maintenance Service in Gravitino + +## 1. Background + +The Table Maintenance Service (TMS) is an alpha feature. The `maintenance/optimizer` package already +has statistics, rule evaluation, strategy recommendation, and job submission (`Updater`, +`Recommender`, providers, `JobSubmitter`), but that core is not hosted as a long-running Gravitino +service. Gaps today: + +1. No stable **server-side commit event** after Iceberg commits through IRC. +2. Hard to centralize configuration, audit, and service metrics for ad hoc runs. +3. No **embedded scheduler** for multi-node safe expand / submit. + +This design loads TMS as a **main-server REST plugin** on port **8090** +(`gravitino.server.rest.extensionPackages`, same pattern as IdP) so colocated IRC can wake +maintenance after commits. + +--- + +## 2. Goals + +1. **In-process plugin** on the main server (Jersey 2 `Feature`). Commit path does **not** use HTTP. +2. **IRC in-process commit event**: after successful Iceberg commits, enqueue commit-triggered + maintenance (`task_instance = {table_id}`); do **not** `runJob` on the IRC thread (§5.2). +3. **Reuse optimizer core** in-process (`Updater` / `Recommender` / job submit). +4. **Job framework**: Spark work stays in Gravitino Jobs; TMS records runs in + `table_maintenance_job` (Validation + submit gates). +5. **Govern Policy reuse**: existing `policy_meta` / Policy APIs; no parallel policy store. +6. **Multi-node safe**: db-scheduler pick + heartbeat; in-flight gated by + `table_maintenance_job.finished_at IS NULL`. Expand / cron / commit task kinds and pools are + defined in §5.2 — not restated here. +7. **Policy triggers + jobOptions** in `policy_version_info.content` (`schedule`, `jobOptions` / + `rewriteOptions`); nearest attachment wins (§5.1). Non-sensitive IRC/Spark client props (e.g. + `uri`, `type`, `io-impl`) live in **`jobOptions`**. +8. **Cluster-static client auth** in **`gravitino.conf`** (`gravitino.maintenance.gravitinoAuth.*` + / `gravitino.maintenance.ircAuth.*`, §7.4): one Gravitino identity and one IRC client auth for + the service — not per-policy and not a DB table. + +--- + +## 3. Non-Goals + +1. Standalone maintenance daemon or dedicated aux Jetty port (e.g. **9301**). +2. Rewrite of optimizer provider / submitter SPIs. +3. Engine-side commit report when engines bypass Gravitino IRC. +4. Commit-path HTTP or Kafka (`POST …/events/iceberg-commit`, health resource). +5. Auto-create a built-in TMS user / role. Operators grant privileges when authorization is on (§6). + +--- + +## 4. Solution Investigations + +### 4.1 Deployment shape + +| Option | Decision | +| ----------------------------- | ------------------------------------------------------ | +| Process-local only | Rejected — no IRC wake / multi-node coordination | +| **In-process plugin on 8090** | **Chosen** — same JVM as IRC; `extensionPackages` | +| Separate long-running process | Rejected — extra deployable | +| Aux Jetty listener (`:9301`) | Rejected — extra port; diverges from IdP-style plugins | + +### 4.2 Scheduler + +TMS needs cluster-safe scheduling for **three** kinds of work (policy→Spark / cron Spark / +commit-triggered Spark) plus durable **`table_maintenance_job`** for Validation and in-flight +occupancy. + +| | **db-scheduler** (Chosen) | JobRunr | ShedLock | Quartz JDBC | +| -------------------------------- | ------------------------- | ------- | ---------- | ----------- | +| License | Apache 2.0 | LGPL v3 | Apache 2.0 | Apache 2.0 | +| Cluster CAS + heartbeat | Yes | Yes | Lock only | Yes (heavy) | +| Fits long-lived 1 + one-shot 2/3 | Yes | Yes | No | Yes | + +**Chosen:** db-scheduler (Apache 2.0, one `scheduled_tasks` table, built-in heartbeat). Three pools: +expand / cron / commit. Reject JobRunr (license), ShedLock (not a scheduler), Quartz (heavy). + +### 4.3 Where Job configuration lives + +| Concern | Rejected | **Chosen** | +| --------------------------- | ------------------------------------------------- | ----------------------------------------------------- | +| Non-auth Spark / IRC params | Extra options table keyed by catalog/schema/table | Policy content `jobOptions` / `rewriteOptions` (§5.1) | +| Client auth binding | Per-policy named auth configs in policy content | Cluster-static keys in `gravitino.conf` (§7.4) | + +--- + +## 5. Proposal + +TMS is an in-process plugin. Policy content defines **what** and **when**; db-scheduler defines +**who runs which unit** under multi-node pick. Writing `scheduled_tasks` does **not** mean every +node executes — pools poll; **N compete, one pick wins**. + +| Table / store | Role | +| -------------------------------------------------------------- | ------------------------------------------------------------------- | +| `policy_meta` / `policy_relation_meta` / `policy_version_info` | Triggers + `jobOptions` / `rewriteOptions` (§5.1) | +| `scheduled_tasks` | ① `policy-expand` + ② `cron-job` + ③ `commit-job` (§5.2) | +| `table_maintenance_job` | Per-run occupancy + before/after `snapshot_id`; submit gates (§5.2) | +| `table_snapshot_statistic` | Stats keyed by Iceberg `snapshot_id` (§5.2.6) | +| `gravitino.conf` | Cluster-static Gravitino / IRC client auth (§7.4) | +| `job_run_meta` | Spark job run record / `runtime_job_template` snapshot | + +```text +Create / enable policy (policy_id = P) + → INSERT ① policy-expand / {policy_id} + execution_time = next crontab (or far-future if onCommit-only) + +crontab due → pick ① (expand pool) + → page candidates → gates → INSERT ② table:{table_id}:{policy_id} + → retain ①; set next crontab due + +IRC commit → upsert ③ commit-job / {table_id} (IRC thread; not pools) + +pick ② (cron pool): + → gate → sample once at S0 → Recommender → one-type runJob if needed → DELETE ② +pick ③ (commit pool): + → gate → resolve onCommit types (§5.1.2) → sample each at S0 → Recommender per type + → one Spark Job chains remaining types in order → DELETE ③ + → Job terminal: sample S1 per policy in the chain → after_snapshot_id=S1, finished_at + (no re-upsert of ③ for “next type”; new IRC commits may upsert ③ again) +``` + +### 5.1 Policy + +Maintenance policies stay on existing metalake Policy APIs. TMS does **not** add +`/api/maintenance/table/policies` CRUD. One policy row can enable both evaluate triggers; use +**two policies** only when maintenance **types** differ. + +#### 5.1.1 Evaluate triggers (`onCommit` + `crontab`) + +Stored in **`policy_version_info.content.schedule`** (not `policy_meta` columns, not +`scheduled_tasks`). + +| Trigger | Meaning | Notes | +| ---------- | ------------------------------------------------------------- | ---------------------------------------------------- | +| `onCommit` | After IRC commit, one Spark Job chains ordered types (§5.1.2) | Compaction / manifest-rewrite / snapshot-expiry only | +| `crontab` | Periodic expand on a crontab expression | Required for orphan-cleanup | + +`crontab` drives **when ① expand runs**. `onCommit` goes through **③**, not ①. +`minIntervalMs` (§7) caps how soon another enqueue/submit may proceed after +`MAX(finished_at)` on `table_maintenance_job` for that `(table, policy)`. + +**`orphan-cleanup` must not use `onCommit`.** Policy create/alter rejects +`schedule.onCommit = true` for orphan-cleanup. Orphan cleanup is **crontab-only**. + +Illustrative content: + +```json +{ + "rewriteOptions": { "target-file-size-bytes": "536870912" }, + "jobOptions": { + "spark.executor.memory": "7g", + "uri": "http://host:9001/iceberg";, + "type": "rest" + }, + "schedule": { "onCommit": true, "crontab": "0 2 * * *" } +} +``` + +| Field | TMS runtime | +| ------------------- | -------------------------------------------------------------------------- | +| `schedule.onCommit` | IRC upserts ③; commit pool submits one Job that chains §5.1.2 order in-Job | +| `schedule.crontab` | Sets / refreshes ① next `scheduled_tasks.execution_time` | +| `jobOptions` | Non-sensitive Spark / IRC client props (`uri`, `type`, memory, …) | + +At least one of `onCommit` or `crontab` should be set for automated maintenance (except +orphan-cleanup: **`crontab` only**). + +**Policy lifecycle → ①:** create/enable → INSERT ①; alter schedule → update ① `execution_time`; +disable/drop → DELETE ① and outstanding ② for that `policy_id`. + +#### 5.1.2 Commit-driven type order + +**`onCommit` allows only** `compaction` → `manifest-rewrite` → `snapshot-expiry` (strict order). +**`orphan-cleanup` is not allowed** on `onCommit`. + +On the commit path for a table, TMS takes the Active, attached, `onCommit`-enabled subset and +submits **one** Spark Job that runs those types **in that fixed order inside the same Job** +(skip missing types or types the Recommender skips; never reorder). Control plane does **not** +submit one Job per type and does **not** re-upsert ③ after a step for the “next type”. + +That single Job’s Spark resources come from merging the chain’s policies’ `jobOptions`: conflicting +numeric resource settings (e.g. `spark.executor.memory`) use the **maximum**. Per-type +`rewriteOptions` / thresholds stay with each step. `minIntervalMs` is **not** part of this merge +(§7.3). + +`commit-job` is one row per `{table_id}` (IRC bursts coalesce). One pick → at most one chained +`runJob` → DELETE ③. A later IRC commit may upsert ③ again for a new round. + +Crontab remains per-policy expand (① per `policy_id`) and one type per ② Job — it does not use +this in-Job chain. + +#### 5.1.3 Job template parameters (`jobOptions`) + +Non-sensitive Spark / strategy / IRC **client** options live in **`policy_version_info.content`** +alongside `schedule` as an inline map. Examples: `spark.executor.memory`, `rewriteOptions`, Iceberg +REST `uri` / `type` / `warehouse` / `prefix` / `io-impl`. They are **not** `policy_meta` columns and +TMS does **not** add a separate options table. + +**Precedence** (first hit wins), matching policy attachment: + +```text +table-attached > schema-attached > catalog-attached +``` + +Policy create/alter **rejects** credential-shaped keys in `jobOptions` / `rewriteOptions` +(`password`, `secret`, `token`, `access-key`, …). Client auth is cluster-static in +`gravitino.conf` (§7.4), not in policy content. Credential-vending props stay on the catalog / +IRC server side. + +`job_run_meta.runtime_job_template` is a **run snapshot** only — not the default config store. + +#### 5.1.4 Client auth (cluster config) + +TMS uses **one** Gravitino client identity and **one** Iceberg REST client auth for the whole +service. There is no per-policy auth switch — operators set +`gravitino.maintenance.gravitinoAuth.*` and `gravitino.maintenance.ircAuth.*` in `gravitino.conf` +(§7.4). Restart (or conf reload, if supported) applies changes. + +Same split as today’s maintenance / optimizer CLI (`--updater-options` vs Spark / IRC job conf). +Each bag is **non-sensitive props ⊕ auth overlay** — auth alone does not fill the bag: + +| Bag | Non-sensitive (examples) | Auth overlay (from `gravitino.conf`) | +| ------------------- | ------------------------------------------------------------- | --------------------------------------- | +| **`updateOptions`** | `gravitino_uri`, `metalake`, updater impl names, … | `gravitino.maintenance.gravitinoAuth.*` | +| **`jobOptions`** | nearest policy `jobOptions` (`uri`, `type`, Spark resources…) | `gravitino.maintenance.ircAuth.*` | + +TMS control plane also uses `gravitinoAuth.*` directly (expand / submit / RBAC), not only via +`updateOptions`. + +**Submit overlay:** + +```text +control plane: gravitinoAuth.* → authenticate Gravitino client → RBAC from token → runJob +runJob payload: + updateOptions ← cluster non-sensitive updater props (gravitino_uri, metalake, …) + ⊕ gravitino.maintenance.gravitinoAuth.* + jobOptions ← nearest policy jobOptions (uri, type, Spark resources, …) + ⊕ gravitino.maintenance.ircAuth.* +``` + +### 5.2 Scheduling and commit + +#### 5.2.1 Three tasks and three pools + +| Kind | `task_name` | When created | Instance key | After pick | +| ------------------------ | --------------- | ---------------------- | ---------------------------------------------------------------- | ----------------------------------- | +| ① Policy → Spark | `policy-expand` | Policy create / enable | `{policy_id}` | Page → INSERT ②; **keep** ① | +| ② Cron Spark | `cron-job` | Written by ① | `table:{table_id}:{policy_id}` or `batch:{batch_id}:{policy_id}` | Short submit → job row → **DELETE** | +| ③ Commit-triggered Spark | `commit-job` | IRC upsert | `{table_id}` | One chained submit → **DELETE** | + +| Pool | Registers | Default threads | conf key (`gravitino.maintenance.`) | +| ------ | --------- | --------------- | ----------------------------------- | +| Expand | ① only | 4 | `scheduler.expand.threads` | +| Cron | ② only | 8 | `scheduler.cron.threads` | +| Commit | ③ only | 4 | `scheduler.commit.threads` | + +**Uniqueness:** PK `(task_name, task_instance)`. Commit bursts coalesce on +`(commit-job, {table_id})`. Prefixes `table:` / `batch:` avoid id ambiguity. + +**Expand paging:** each ① pick inserts at most `expand.enqueueBatchSize` (default **100**) ② rows; +cursor in ① `task_data` while paging, then cleared. Cron ②: compaction / manifest-rewrite / +orphan-cleanup stay one table per job; **snapshot-expiry** may batch +(`batch:{batch_id}:{policy_id}`). Commit ③: one table, one Job, up to three types chained in-Job +(§5.1.2). + +```text +Spark / Flink / Trino → IRC (:9001) commit + → EventListener (IcebergUpdateTableEvent) → upsert ③ {table_id} + +Node A / B / C — three pools poll; N compete, one pick + ├─ expand: pick ① → INSERT ② → retain ① + ├─ cron: pick ② → one-type runJob → INSERT job → DELETE ② + └─ commit: pick ③ → resolve chain → one chained runJob → DELETE ③ +``` + +#### 5.2.2 In-process commit event + +| Requirement | Detail | +| ----------- | --------------------------------------------------------------------------------------------- | +| Deployment | IRC and main server share **one JVM** | +| Transport | IRC `EventListenerPlugin` on successful `IcebergUpdateTableEvent` — **no** HTTP, **no** Kafka | +| Enqueue | Listener upserts `(commit-job, {table_id})` (must stay short) | +| Execute | **`commit.threads`** picks ③; resolve + gate + short submit | + +Register the listener with `gravitino.eventListener.names` / `{name}.class` (§7.1). The handler +must only enqueue ③ — it does **not** call `runJob`, does **not** use expand/cron/commit pools, and +does **not** build the onCommit type chain (that happens when the commit pool picks ③). + +#### 5.2.3 Execute path + +```text +① due (expand.threads): + load policy → page candidates → expand gates → INSERT ② → retain ① / next crontab + +② due (cron.threads): + in-flight re-check + → S0 = currentSnapshotId; sample once → UPSERT table_snapshot_statistic (…, policy_id, S0) + → Recommender (S0 + that policy) + → if go: updateOptions←updater props⊕gravitinoAuth; jobOptions←policy⊕ircAuth (§7.4) → runJob + → INSERT table_maintenance_job (policy_id, before_snapshot_id=S0, finished_at=NULL) + → else: no runJob + → DELETE ② → return + +③ due (commit.threads): + in-flight re-check (any policy in the prospective chain) + → resolve Active onCommit types in order (§5.1.2) + → S0 = currentSnapshotId; sample once per policy in the chain → UPSERT stats + → Recommender per type → drop skipped types; if chain empty → DELETE ③ → return + → updateOptions←updater props⊕gravitinoAuth; merge jobOptions (Spark max) ⊕ ircAuth (§7.4) → one runJob + (Spark runs remaining types in order inside this Job) + → INSERT table_maintenance_job (policy_id = first step; full chain in runtime template; + before_snapshot_id=S0, finished_at=NULL) + → DELETE ③ → return + +Job terminal listener: + S1 = currentSnapshotId; sample per policy touched by the Job → UPSERT stats + → UPDATE job SET after_snapshot_id=S1, finished_at=… + # no re-upsert of ③ for next type +``` + +**Why DELETE ②/③; keep ①:** ① is the durable per-policy expand lease. ②/③ are one-shot submit +units; Spark lifetime and anti-double-submit live on `table_maintenance_job` + Job listener / +reconcile. + +**Metrics / snapshot drift (Amoro-style, one evaluate per pick):** + +Control-plane sampling is **once per ②/③ claim**. Persist that sample under Iceberg +`snapshot_id` in `table_snapshot_statistic`, then decide. Do **not** re-sample in a loop when HEAD +moves (same pattern as Amoro / Floe / OpenHouse). Stats for `S0` stay valid as history even if HEAD +advances; they may be stale for “current” maintenance need — next `cron-job` / `commit-job` will +sample a newer snapshot. + +| Outcome after one sample | Action | +| ------------------------------------- | ---------------------------------------------------------------------- | +| Recommender says maintain | `runJob`; Job / Iceberg OCC handles concurrent commits | +| Recommender says skip, or gates block | No `runJob`; still **DELETE** ②/③ — this round is **complete** | +| Snapshot moves during/after sample | Do **not** re-sample; end the round; fresher state on the next wake-up | + +**Expand gates** (on ①, before INSERT ②): + +1. In-flight for `(table_id, policy_id)` (`finished_at IS NULL`) → skip. +2. `MAX(finished_at)` within resolved `minIntervalMs` → skip. + +**Submit path** re-checks in-flight; if occupied, **DELETE** the scheduled row and return (no second +`runJob`). Sample **once** at `S0`, upsert history, then recommend. + +**Crontab timeline** (`0 2 * * *`): create → INSERT ① due next 02:00 → pick ① → INSERT many ② due +now → retain ① with next crontab → pick each ② → short submit → DELETE ②. Expand due time ≠ Spark +wall-clock stamp on ②. + +#### 5.2.4 Multi-node coordination + +Every node runs db-scheduler. IRC on the commit node upserts ③; when due, nodes compete and +**exactly one** claim runs (CAS + heartbeat). Missed heartbeats free a hung **short callback** only. + +```text +Policy create → INSERT ① +crontab due → pick ① → INSERT many ② → retain ① +IRC commit → upsert ③ {table_id} +Node A / B / C + ├─ expand: pick ① → INSERT ② → retain ① + ├─ cron: pick ② → short submit → DELETE ② + ├─ commit: pick ③ → one chained submit → DELETE ③ + └─ picker dies → missed heartbeats → instance runnable again +``` + +**Not** “write `scheduled_tasks` ⇒ every node executes.” **Yes** “when due ⇒ every node may try; +exactly one claim runs that instance.” + +`scheduled_tasks` is owned by db-scheduler (upstream DDL). Illustrative usage: + +```text +PK (task_name, task_instance) +① policy-expand / {policy_id} task_data empty or cursor +② cron-job / table:…|batch:… task_data = { tableIds, policyIds } +③ commit-job / {table_id} task_data = { tableIds, policyIds } # chain built at pick +②/③ DELETE after short submit; ① deleted only on policy disable/drop/replace +``` + +#### 5.2.5 Per-run table `table_maintenance_job` + +One row per Gravitino Job (`job_id`): in-flight / `minIntervalMs` gates, plus Iceberg +**`before_snapshot_id` / `after_snapshot_id`** for Jobs Validation. Metric **values** live in +`table_snapshot_statistic` (§5.2.6), not as JSON on this row. +`minIntervalMs` uses this row’s `finished_at`, not `job_run_meta.job_finished_at`. +Column name is **`job_id`** (Jobs API / `JobHandle` wording); it stores the same numeric id as +`job_run_meta.job_run_id`. Surrogate **`id`** is the table PK. + +| Column | Type | Notes | +| -------------------- | -------------------------- | ----------------------------------------------------------------------------------------------- | +| `id` | `BIGINT UNSIGNED` PK | Auto increment | +| `job_id` | `BIGINT UNSIGNED NOT NULL` | Unique; maps to `job_run_meta.job_run_id` | +| `table_id` | `BIGINT UNSIGNED NOT NULL` | `table_meta` PK | +| `policy_id` | `BIGINT UNSIGNED NOT NULL` | Cron: that Job’s policy. Commit chain: first step’s `policy_id`; full chain in runtime template | +| `before_snapshot_id` | `BIGINT NOT NULL` | Iceberg snapshot at sample / submit | +| `after_snapshot_id` | `BIGINT NULL` | Iceberg snapshot after job terminal; null while pending | +| `finished_at` | `BIGINT UNSIGNED NULL` | Epoch millis; **null = in-flight** | + +```sql +CREATE TABLE IF NOT EXISTS `table_maintenance_job` ( + `id` BIGINT(20) UNSIGNED NOT NULL AUTO_INCREMENT COMMENT 'auto increment id', + `job_id` BIGINT(20) UNSIGNED NOT NULL COMMENT 'job id; maps to job_run_meta.job_run_id', + `table_id` BIGINT(20) UNSIGNED NOT NULL COMMENT 'table id from table_meta', + `policy_id` BIGINT(20) UNSIGNED NOT NULL COMMENT 'policy id from policy_meta', + `before_snapshot_id` BIGINT(20) NOT NULL COMMENT 'Iceberg snapshot id at sample/submit', + `after_snapshot_id` BIGINT(20) NULL COMMENT 'Iceberg snapshot id after job; null while pending', + `finished_at` BIGINT(20) UNSIGNED NULL COMMENT 'end time; null = in-flight', + PRIMARY KEY (`id`), + UNIQUE KEY `uk_job_id` (`job_id`), + KEY `idx_tmj_table_policy_finished` (`table_id`, `policy_id`, `finished_at`), + KEY `idx_tmj_before_sid` (`table_id`, `before_snapshot_id`), + KEY `idx_tmj_after_sid` (`table_id`, `after_snapshot_id`) +) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin + COMMENT 'per-run TMS job: snapshot pointers + submit gates'; +``` + +**Validation:** load stats from `table_snapshot_statistic` where +`(table_id, policy_id, snapshot_id)` matches the job’s `table_id` / `policy_id` / +`before_snapshot_id` or `after_snapshot_id`. Do not store metric JSON on the job row. + +#### 5.2.6 Table snapshot statistic (`table_snapshot_statistic`) + +Per-policy Iceberg table statistics keyed by **`snapshot_id`**. Used by TMS sample, Recommender, +and Jobs Validation. **One row = one `(table_id, policy_id, snapshot_id)`** — all metrics in +`statistic_value` (JSON). + +**Why `policy_id`:** compaction, manifest-rewrite, snapshot-expiry, orphan-cleanup may sample the +same table snapshot with **different** metric payloads / Validation needs. Without `policy_id`, +UPSERT on `(table_id, snapshot_id)` would overwrite across types/policies. + +| Column | Type | Notes | +| ----------------- | -------------------------- | ------------------------------------------- | +| `id` | `BIGINT UNSIGNED` PK | Auto increment | +| `table_id` | `BIGINT UNSIGNED NOT NULL` | `table_meta` PK | +| `policy_id` | `BIGINT UNSIGNED NOT NULL` | `policy_meta.policy_id` | +| `snapshot_id` | `BIGINT NOT NULL` | Iceberg snapshot id | +| `statistic_value` | `MEDIUMTEXT NOT NULL` | JSON payload of all metrics for this sample | + +**Unique key:** (`table_id`, `policy_id`, `snapshot_id`). +**Indexes:** (`table_id`); (`table_id`, `policy_id`). + +```sql +CREATE TABLE IF NOT EXISTS `table_snapshot_statistic` ( Review Comment: Why do we need this table? Could we reuse the existing table about statistics or expand existing table? -- This is an automated message from the Apache Git Service. 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