Problemsby GlyphDuckDB costs outgrow the value it gives
4 posts from 4 people4d activeFading, +0 this week
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The posts behind it
DuckDB 2.0.0 LEFT JOIN cardinality estimate regression
### What happens? DuckDB 2.0.0 has two cardinality-estimation problems that can affect join planning: a multi-relation LEFT JOIN can be estimated below its preserved input, and an expression equality such as `ts % 7 = 0` can be estimated using the distinct count of the...
InitializeGlobalState forces full file expansion via GetTotalFileCount(), defeating LIMIT on lazily-expanded file lists
`TableFunctionMultiFileWrapper::InitializeGlobalState` unconditionally expands the entire file list at scan startup: For a `MultiFileList` whose expansion is cheap this is free. For one where enumerating a file requires reading remote metadata, it forces the whole cost before a...
`LEAD` advances a sequence too many times
### What happens? A legal `LEAD(nextval(...))` over 5000 rows returns sequence values as high as 9096 and advances the sequence to 9097 instead of advancing it to 5001. ### To Reproduce ### Code ### Expected | minimum | maximum | total | rows | after | | ---: | ---: | ---: |...
C extension API: expose table filters to table functions (filter pushdown)
...server-side, and on real tables that ratio is far larger. But there appears to be no way to receive filters through the C API. ### What's missing Checked against v1.5.5. `src/include/duckdb_extension.h` contains no occurrence of `filter`, and the two in `src/include/duckdb.h`...
Companies and products named
About this problem
Evidence
4 posts from 4 people in 1 place, about 1 a week over 54 days. Mostly on duckdb/duckdb. Tools named alongside: AWS.
Frustration Frustration 0 of 3· Seen on GitHub issues
How it was grouped
Posts that state a pain and match the "observability-cost" rule about DuckDB. First post Aug 30, 2026, latest Oct 22, 2026. Corroborated: 3 or more posts from 2 or more people or places. Method
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Other DuckDB problems
DuckDB upgrades break working setups
37 posts from 28 people on GitHub issues.
DuckDB users keep filing bugs
Top post: "latest alpha DuckDB 2.0 with Quack server on Windows/Linux got `Authentication failed` since several days ago", one of 23 posts from 15 people on GitHub issues.
Trouble with DuckDB internal
Top post: "duckdb 2.0.0 fails to launch on BE: `INTERNAL Error: The time zone data is corrupt`", one of 14 posts from 7 people on GitHub issues.
DuckDB error messages are cryptic
11 posts from 7 people on GitHub issues.
Trouble with DuckDB returns
Top post: "Comparison simplification returns an incorrect result when a narrowing `DECIMAL` cast is used", one of 9 posts from 9 people on GitHub issues.
Trouble with DuckDB join
Top post: "Segfault in `dense_rank() OVER ()` over a RIGHT_ANTI hash join that returns its unmatched rows", one of 9 posts from 8 people on GitHub issues.
Trouble with DuckDB column
Top post: "2.0 alpha: comparing a CASE/split_part result to a constant fails with BindBuiltinScalarFunction did not", one of 7 posts from 5 people on GitHub issues.
Trouble with DuckDB cast
Top post: "TRY_CAST of an empty BLOB to BIT escapes a non-fallible __cast and invalidates the database", one of 7 posts from 6 people on GitHub issues.
Trouble with DuckDB null
Top post: "DuckDB: `HAVING` of `(φ IS TRUE) OR NOT (φ IS TRUE) AND …` is empty for a NULL `φ`, but the same boolean as", one of 6 posts from 6 people on GitHub issues.
Trouble with DuckDB values
Top post: "ManualVuln37 Unbounded Recursion in EncodeVariantValue Causes Stack Overflow via variant_comparator on Deeply", one of 6 posts from 6 people on GitHub issues.
Experiments on DuckDB are hard to reproduce and track
6 posts from 4 people on GitHub issues.
Trouble with DuckDB parquet
Top post: "External file cache range metadata grows for deleted local Parquet files in v1.5.6 despite buffer eviction", one of 5 posts from 5 people on GitHub issues.
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