CockroachDB: Decoding TestExplainRedactDDL Failures

by Omar Yusuf 52 views 
=== RUN   TestExplainRedactDDL/ExplainAnalyze/NoMode/Verbose
    explain_test_util.go:123: pq: internal error: unable to encode table key: *tree.DLTree
    explain_test_util.go:127: encountered non-internal error: pq: duplicate key value violates unique constraint "ta̧ble_1_pkey"
        EXPLAIN ANALYZE (VERBOSE, REDACT) INSERT INTO defaultdb.public.ta̧ble_1 AS tab_16 (col1_0) VALUES ('5874897-12-31':::DATE)
        
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/NoMode/Verbose (0.03s)
=== RUN   TestExplainRedactDDL/ExplainAnalyze/Plan/Catalog
    explain_test_util.go:123: pq: internal error: unable to encode table key: *tree.DLTree
    explain_test_util.go:127: encountered non-internal error: pq: duplicate key value violates unique constraint "ta̧ble_1_pkey"
        EXPLAIN ANALYZE (PLAN, CATALOG, REDACT) INSERT INTO defaultdb.public.ta̧ble_1 AS tab_16 (col1_0) VALUES ('5874897-12-31':::DATE)
        
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/Plan/Catalog (0.03s)
=== RUN   TestExplainRedactDDL/ExplainAnalyze/Plan/Viz
    explain_test_util.go:123: pq: internal error: unable to encode table key: *tree.DLTree
    explain_test_util.go:127: encountered non-internal error: pq: duplicate key value violates unique constraint "ta̧ble_1_pkey"
        EXPLAIN ANALYZE (PLAN, VIZ, REDACT) INSERT INTO defaultdb.public.ta̧ble_1 AS tab_16 (col1_0) VALUES ('5874897-12-31':::DATE)
        
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/Plan/Viz (0.03s)
=== RUN   TestExplainRedactDDL/ExplainAnalyze/NoMode/Shape
    explain_test_util.go:123: pq: internal error: unable to encode table key: *tree.DLTree
    explain_test_util.go:127: encountered non-internal error: pq: duplicate key value violates unique constraint "ta̧ble_1_pkey"
        EXPLAIN ANALYZE (SHAPE, REDACT) INSERT INTO defaultdb.public.ta̧ble_1 AS tab_16 (col1_0) VALUES ('5874897-12-31':::DATE)
        
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/NoMode/Shape (0.03s)
=== RUN   TestExplainRedactDDL/ExplainAnalyze/NoMode/Types
    explain_test_util.go:123: pq: internal error: unable to encode table key: *tree.DLTree
    explain_test_util.go:127: encountered non-internal error: pq: duplicate key value violates unique constraint "ta̧ble_1_pkey"
        EXPLAIN ANALYZE (TYPES, REDACT) INSERT INTO defaultdb.public.ta̧ble_1 AS tab_16 (col1_0) VALUES ('5874897-12-31':::DATE)
        
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/NoMode/Types (0.04s)
=== RUN   TestExplainRedactDDL/ExplainAnalyze/Plan
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/Plan (0.22s)
=== RUN   TestExplainRedactDDL/ExplainAnalyze/Plan/Memo
    explain_test_util.go:123: pq: internal error: unable to encode table key: *tree.DLTree
    explain_test_util.go:127: encountered non-internal error: pq: duplicate key value violates unique constraint "ta̧ble_1_pkey"
        EXPLAIN ANALYZE (PLAN, MEMO, REDACT) INSERT INTO defaultdb.public.ta̧ble_1 AS tab_16 (col1_0) VALUES ('5874897-12-31':::DATE)
        
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/Plan/Memo (0.03s)
=== RUN   TestExplainRedactDDL/ExplainAnalyze/Plan/NoFlag
    explain_test_util.go:123: pq: internal error: unable to encode table key: *tree.DLTree
    explain_test_util.go:127: encountered non-internal error: pq: duplicate key value violates unique constraint "ta̧ble_1_pkey"
        EXPLAIN ANALYZE (PLAN, REDACT) INSERT INTO defaultdb.public.ta̧ble_1 AS tab_16 (col1_0) VALUES ('5874897-12-31':::DATE)
        
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/Plan/NoFlag (0.03s)
=== RUN   TestExplainRedactDDL/ExplainAnalyze/Plan/Types
    explain_test_util.go:123: pq: internal error: unable to encode table key: *tree.DLTree
    explain_test_util.go:127: encountered non-internal error: pq: duplicate key value violates unique constraint "ta̧ble_1_pkey"
        EXPLAIN ANALYZE (PLAN, TYPES, REDACT) INSERT INTO defaultdb.public.ta̧ble_1 AS tab_16 (col1_0) VALUES ('5874897-12-31':::DATE)
        
--- FAIL: TestExplainRedactDDL/ExplainAnalyze/Plan/Types (0.04s)

This article dives into the recent failure observed in the CockroachDB test suite, specifically focusing on the pkg/ccl/testccl/sqlccl/sqlccl_test.TestExplainRedactDDL test. We'll break down the error messages, discuss the potential causes, and outline the steps to resolve this issue. Let's explore the intricacies of this failure to gain a clearer understanding of the underlying problem and its implications for CockroachDB.

Decoding the TestExplainRedactDDL Failure

The TestExplainRedactDDL failure in CockroachDB points to some interesting underlying issues within the system. The error messages clearly indicate two primary problems:

  1. Internal Error: Unable to encode table key: *tree.DLTree: This suggests a serialization issue where the system is failing to encode a specific data structure (tree.DLTree) used internally. This is quite critical since the encoding process is fundamental for data storage and retrieval within a database system like CockroachDB.

  2. Non-Internal Error: Duplicate key value violates unique constraint "ta̧ble_1_pkey": This error signals a violation of the primary key constraint on the table ta̧ble_1. In simpler terms, the test is attempting to insert a row with a primary key that already exists, which is a no-no in relational databases.

These errors cropped up across multiple test variations, including ExplainAnalyze/NoMode/Verbose, ExplainAnalyze/Plan/Catalog, ExplainAnalyze/Plan/Viz, ExplainAnalyze/NoMode/Shape, ExplainAnalyze/NoMode/Types, ExplainAnalyze/Plan, ExplainAnalyze/Plan/Memo, ExplainAnalyze/Plan/NoFlag, and ExplainAnalyze/Plan/Types. The consistency of these failures hints at a systemic issue rather than an isolated incident. It means whatever the root cause is, it is affecting various parts of the EXPLAIN ANALYZE functionality when used with redaction (REDACT).

Investigating the Internal Error: Unable to encode table key: *tree.DLTree

Let's zoom in on the internal error: unable to encode table key: *tree.DLTree. This cryptic message indicates a problem during the encoding of a tree.DLTree object, which is a data structure used within CockroachDB. This encoding process is crucial for persisting data to storage and transmitting it across the network. The fact that this error occurs specifically during the TestExplainRedactDDL suggests that it might be related to how the EXPLAIN ANALYZE statement interacts with the redaction feature. Redaction involves masking or removing sensitive data from the output, and it seems like the process of encoding the execution plan (which involves tree.DLTree) is failing when redaction is enabled.

To tackle this, we need to dive into the code and understand how tree.DLTree is used in the context of EXPLAIN ANALYZE and redaction. Some potential areas of investigation include:

  • Serialization Logic: The encoding/decoding logic for tree.DLTree might have a bug that's triggered when redaction is enabled. We need to examine the code that handles the serialization of this data structure and see if any specific conditions cause it to fail.
  • Redaction Implementation: The redaction process itself might be interfering with the encoding. It's possible that the redaction logic is modifying the tree.DLTree object in a way that makes it unencodable.
  • Concurrency Issues: If the encoding process is happening concurrently with other operations (like redaction), there might be a race condition leading to the failure. Analyzing the concurrency aspects of the code is crucial.

Analyzing the Non-Internal Error: Duplicate Key Violation

Now, let's tackle the **`duplicate key value violates unique constraint