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Author SHA1 Message Date
sonika-shah
0a07caefc2
fix(migration): preempt PDTS duplicates and recover invalid index in 1.12.9 (#28238)
* fix(migration): preempt PDTS duplicates and recover invalid index in 1.12.9

CREATE UNIQUE INDEX CONCURRENTLY aborts when it hits existing duplicate
keys but leaves an invalid index behind. On migration retry, IF NOT EXISTS
no-ops successfully and gets checksum-logged, after which ADD CONSTRAINT
USING INDEX fails permanently with "index ... is not valid". Hit at a
customer with two duplicate table.systemProfile rows on a 10M-row PDTS.

Adds two idempotent statements before the existing constraint build:

- DO block: drops the invalid index and clears its migration-log entry
  when indisvalid=false. No-op on fresh DBs and on already-migrated
  environments (where the index is valid and owned by the constraint).

- DELETE: collapses duplicate rows via single hash aggregate on the
  4-column key + targeted self-join. Reads only key columns (no json
  scan), only touches rows in actual duplicate groups, no-op on clean DBs.
  Efficient on multi-million-row PDTS tables.

Existing CREATE INDEX / ALTER TABLE / ANALYZE statements byte-identical
so checksum-matched skips for already-migrated environments still apply.

* fix(migration): self-heal in one pass + schema-scoped invalid-index probe

Addresses Copilot review on #28238:

1. One-pass self-heal. MigrationFile.parseSQLFiles filters already-logged
   statements at parse time (MigrationFile.java:83). Clearing the CREATE
   log entry from inside a DO block doesn't bring CREATE back into the
   current pass's execution list — it would only re-run on the next
   migration cycle, leaving the same-pass ALTER to fail again. Replace
   the "DROP + clear log" pattern with "DROP + rebuild inline" so a
   valid index exists before ALTER runs in the same pass.

   Inline rebuild uses non-concurrent CREATE UNIQUE INDEX, which takes a
   brief ACCESS EXCLUSIVE lock on the table. Acceptable because this
   path fires only when the environment is already in a degraded state.
   Normal-path customers go through the CONCURRENTLY build below.

2. Schema-scoped invalid-index probe. pg_class.relname is not
   schema-unique. Anchor the lookup via
   i.indrelid = 'profiler_data_time_series'::regclass and DROP by index
   OID (invalid_idx::regclass), so an invalid index with the same name
   in another schema cannot accidentally trigger this branch.

Existing CREATE INDEX / ALTER TABLE / ANALYZE statements byte-identical
to before this PR, so checksum-matched skips still apply for
already-migrated environments. Test gap (Copilot's third comment) for
the recovery scenario tracked as follow-up — existing migration tests
in MigrationWorkflowReprocessingTest are mock-based; verifying recovery
end-to-end needs Postgres integration infrastructure.

* chore(migration): trim verbose comments in 1.12.9/postgres/schemaChanges.sql

Statement bodies unchanged — checksums identical. Detailed mechanism
write-ups live in the commit log / PR description; the file keeps just
the load-bearing intent comment above each statement.

* fix(migration): scope PDTS dedup to operation IS NOT NULL

Addresses Copilot review on PR #28238 discussion r3264066840.

Postgres UNIQUE treats NULLs as DISTINCT by default, so the constraint
on (entityFQNHash, extension, operation, timestamp) permits multiple
rows where operation IS NULL — i.e. table.tableProfile and
table.columnProfile rows that share the other key columns.

The previous dedup used GROUP BY which treats NULLs as equal, so it
would have collapsed retry-induced tableProfile / columnProfile pairs
that the restored constraint never actually blocked. Restricting the
subquery to operation IS NOT NULL (plus a defensive entityFQNHash IS
NOT NULL) aligns dedup with constraint semantics.

DMG's customer rows were all table.systemProfile (operation = INSERT),
so this still removes the customer dupes correctly. tableProfile /
columnProfile retry duplicates — if they exist — stay as-is, which is
the same outcome the unique constraint would produce on its own.

* perf(migration): boost work_mem / maintenance_work_mem for PDTS dedup at scale

Mirrors the tuning pattern from 1.9.9/postgres/postDataMigrationSQLScript.sql
(same table, same operation class). On 50M-row PDTS the dedup DELETE's hash
aggregate spills to disk with default work_mem=4MB, adding ~30-60s of disk
I/O. Bumping work_mem to 256MB keeps the aggregate in memory;
maintenance_work_mem=512MB lets CREATE UNIQUE INDEX CONCURRENTLY sort in
memory too.

Session-level (not SET LOCAL) because schemaChanges runs in autocommit
(CREATE INDEX CONCURRENTLY requires it) — SET LOCAL would reset between
statements. RESET at the end of the file restores defaults before the
connection returns to the Hikari pool.

Expected runtime impact at customer scale:
  20M rows:  ~30s tuned vs ~40s default
  50M rows:  ~40s tuned vs ~90s default (avoids spill)

* chore(migration): trim comments on PDTS dedup additions

* chore(migration): drop 1.9.9 reference from mem comment
2026-05-20 18:27:33 +05:30
sonika-shah
17c3b8b9b2
fix(profiler): N+1 / missing-index regression on /tables/.../columns?fields=profile (#3488) (#27746)
* fix(profiler): N+1 / missing-index regression on /tables/.../columns?fields=profile (#3488)

Root cause
----------
The 1.9.9 migration introduced two separate index regressions on
`profiler_data_time_series`:

1. **PostgreSQL**: `schemaChanges.sql` explicitly dropped the unique
   constraint `profiler_data_time_series_unique_hash_extension_ts`
   (entityFQNHash, extension, operation, timestamp) to allow altering the
   generated `operation` column expression, but never recreated it.  After
   the migration the table kept only the `(extension, timestamp)` index,
   which is useless for queries filtering by `entityFQNHash`.

2. **MySQL/both**: `postDataMigrationSQLScript.sql` created temporary indexes
   (idx_pdts_entityFQNHash, idx_pdts_composite, etc.) for its bulk UPDATE
   pass and then dropped **all** of them, including the only index covering
   `entityFQNHash`.

The batch query issued by `getLatestExtensionsBatch()` when
`fields=profile` is requested:

  SELECT entityFQNHash, MAX(timestamp) FROM profiler_data_time_series
  WHERE entityFQNHash IN (...N hashes...) AND extension = 'table.columnProfile'
  GROUP BY entityFQNHash

required an `(entityFQNHash, extension, timestamp)` index.  Without it the
database performs a full table scan.  On production deployments with
millions of profiler rows this caused 100+ second response times (Grafana:
106 770 ms; 99 % in DB; 93 dbOps).  Without `profile` in the fields param
the same endpoint returned in ~150-220 ms.

A secondary N+1 bug existed independently of the index: `customMetrics`
in fields called `getCustomMetrics(table, column)` once per paginated
column, issuing up to N identical queries against `entity_extension` and
then filtering in Java.

Fix
---
* **migration 2.0.2** (MySQL + PostgreSQL): `CREATE INDEX IF NOT EXISTS
  idx_pdts_fqnhash_ext_ts ON profiler_data_time_series(entityFQNHash,
  extension, timestamp)`.  The `IF NOT EXISTS` guard makes the migration
  safe to re-run and handles both upgrade and fresh-install paths.

* **`getTableColumnsInternal`** — `customMetrics` block: fetch all column
  custom metrics for the table in one query, group by column name in Java,
  then distribute.  Reduces N queries to 1.

* **`getTableColumnsInternal`** — `profile` block: skip the duplicate
  `populateEntityFieldTags` call when `tags` was already fetched earlier in
  the same request, saving one prefix-scan on `tag_usage` per request.

Related: PR #26855 (fixed N+1 tag queries on the list-tables path but left
the profiler-index and customMetrics N+1 untouched on the columns sub-path).

* fix(profiler): restore unique constraint on profiler_data_time_series + batch column extension/customMetrics fetch

Move the migration from 2.0.2/ to 1.12.8/ and switch from a non-unique
covering index to restoring the original unique constraint dropped in
1.9.9. The two-phase CREATE UNIQUE INDEX CONCURRENTLY + ADD CONSTRAINT
USING INDEX pattern avoids the ACCESS EXCLUSIVE lock on the hot
profiler_data_time_series table during the upgrade. Closes the 1.9.9
regression and brings Postgres back in line with MySQL (which never lost
the constraint). The leading (entityFQNHash, extension) prefix serves
the column-profile batch query — same shape MySQL has been running
without 504s. MySQL needs no migration.

Java side, eliminates two more N+1 patterns that compound the latency at
customer scale:

* getTableColumnsInternal extension block: replaced per-column
  getColumnExtension() loop with a single getExtensionsByJsonSchema()
  call, grouped by column FQN-hash in Java.
* searchTableColumnsInternal customMetrics block: applied the same
  batch-fetch pattern already used in getTableColumnsInternal, replacing
  per-column getCustomMetrics() with one getExtensions() call.

New DAO method on EntityExtensionDAO:
  getExtensionsByJsonSchema(id, jsonSchema) — selects extensions for a
  table id filtered by the jsonschema discriminator. Required because
  column extensions are stored with MD5-hashed extension keys and have
  no shared prefix the existing getExtensions(id, prefix) could use.

* chore(profiler): address review feedback — empty-list literal + accurate test comments

* Replace `new ArrayList<>()` default in `metricsByColumn.getOrDefault(...)`
  with `List.of()` at both call sites in `TableRepository` (getTableColumnsInternal
  and searchTableColumnsInternal). `getOrDefault` evaluates its default eagerly,
  so the new ArrayList allocates per-column even when the key is found —
  unnecessary work on a hot path.

* Reword two stale test comments in `test_getColumnsWithProfileField_correctnessAndNoBatchRegression`:
  - "all four field combinations" → "the three field combinations exercised below"
  - "(c) duplicate populateEntityFieldTags must not run twice" → describe the
    observable contract the assertions actually verify (tags + profile both
    present), not the internal call count.

* fix(profiler): force outer index scan in getLatestExtensionsBatch by pushing IN list to the join

The getLatestExtensionsBatch query was the right shape for correctness but
the planner — on Postgres at customer scale, with the new unique constraint
in place — was still choosing a parallel sequential scan over the full
profiler_data_time_series table for the outer side of the JOIN, rather than
a merge join with index scan on both sides.

Inner subquery: filtered by `entityFQNHash IN (...)`, used the index.
Outer: only filtered by `p.extension = :extension`, no IN list, planner
couldn't infer the transitive constraint that p.entityFQNHash must equal
one of the inner hashes (because it's enforced through the JOIN ON clause,
not a WHERE predicate). Result: full table scan reading 6.7M+ rows even
when the actual answer is 23 rows.

Adding the redundant `AND p.entityFQNHash IN (<entityFQNHashes>)` to the
outer WHERE makes the constraint explicit. The result set is unchanged
(implied by the join condition), but the planner can now use the unique
index for the outer access too.

Verified on the AUT dump (6.94M-row pdts):
  EXPLAIN of the batch query: 7,234ms → 79ms (Hash Join + Parallel Seq
  Scan → Merge Join + Index Only Scan).
  Live API /columns?fields=profile&include=all: 6-36 seconds → 22-28ms
  (warm) / 1.9s (very first call). 250-1000x improvement, depending on
  cache state.

Same SQL works on both engines; no @ConnectionAwareSqlQuery split needed.

* test(profiler): shorten classification/tag fixture names in IT to fit varchar(256)

The IT fixture for test_getColumnsWithProfileField_correctnessAndNoBatchRegression
was building a tagFQN of `<classification>.<tag>` where each part went through
TestNamespace.prefix(). With the descriptive method name (62 chars) + class
name (15 chars) + namespace UUID (32 chars) plus the `profile_test_cls` /
`profile_test_tag` base names (16 chars each), the resulting tagFQN was 263
characters — over the tag_usage.tagFQN VARCHAR(256) limit:

  ERROR: value too long for type character varying(256)

Shorten the fixture base names from `profile_test_cls`/`profile_test_tag` to
`cls`/`tag`. The namespace prefix already encodes test isolation (class +
method + UUID), so the base name doesn't need to repeat that context.

New tagFQN length: 237 chars (cls__<32>__TableResourceIT__<62>.tag__<32>__TableResourceIT__<62>),
comfortably under 256.

* fix(table): include extensionKey in column-extension deserialize warn log

Addresses gitar-bot review on PR #27746: the warning log on failed column-
extension deserialization only had table.getId(), so operators could not
pinpoint which row was bad. Add record.extensionName() (the entity_extension
row key) to the log. No extra iteration - record is already in scope inside
the catch.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* chore(migration): move profiler unique-constraint migration to 1.12.9

1.12.8 was already published with the PII classification fix from #27910.
Move the profiler_data_time_series unique-constraint restore (this PR's
postgres migration) to 1.12.9 so customers upgrading past the published
1.12.8 still pick it up.

Add a MySQL placeholder schemaChanges.sql for 1.12.9 consistent with the
1.12.7 convention — MySQL was unaffected by the 1.9.9 regression
(MODIFY COLUMN re-evaluates generated expressions in place without
touching the constraint, so MySQL still has the constraint from 1.1.5).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* refactor(table): extract batchFetchCustomMetricsByColumn helper

Addresses PR #27746 Copilot review:
- Dedupe custom-metric batch logic between getTableColumnsInternal and
  searchTableColumnsInternal.
- Reword IT inline comment to reflect what the test actually validates
  (completes within timeout + correct profiles) instead of claiming it
  inspects query plans.

---------

Co-authored-by: Claude <noreply@anthropic.com>
2026-05-14 06:56:39 -07:00