ClickHouse/clickhouse-java

ClickHouse Java Clients & JDBC Driver

Stars: 1.6k
Forks: 637
Open beginner issues: 10
Indexed issues: 157
Avg merge: 2d 12h
Merged PRs (30d): 28

Dominant language: Java
License: Apache-2.0
Last GitHub push: Sep 19, 2026
Latest indexed: Sep 15, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: No beginner labels indexed

Beginner friendly Everything

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156 open issues indexed

[jdbc-v2] Fix ArrayResultSet after-last cursor state Open

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

ClickHouse/clickhouse-java#3143 · Opened Sep 18, 2026
[client-v2] NativeFormatReader fails for non-null values of Nullable(String) Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 74/100

ClickHouse/clickhouse-java#3137 · 1 comment · Opened Sep 17, 2026
PR #3073 (0.9.9 patch) never forward-ported the 159 retryable again and setQueryTimeout does not set max_execution_time on main/0.10.0 Open

Difficulty 4/5 3-5 days Newbie friendliness 55/100

ClickHouse/clickhouse-java#3136 · 2 comments · Opened Sep 17, 2026
client-v2: serializePrimitiveData rejects or silently corrupts String values for UInt64, UUID, Date and DateTime Open

area:data-type bug client-api-v2 jdbc-v2

Difficulty 3/5 1-2 days Newbie friendliness 82/100

ClickHouse/clickhouse-java#3132 · 1 comment · Opened Sep 14, 2026
jdbc-v2: ANTLR4 parser backends report a source table as the INSERT target, writing rows into the wrong table Open

area:jdbc-insert area:sql-parser bug jdbc-v2

Difficulty 3/5 1-2 days Newbie friendliness 78/100

ClickHouse/clickhouse-java#3129 · Opened Sep 11, 2026
[jdbc-v2] setObject(LocalDateTime) applies the JVM timezone and stores a shifted value Open

area:data-type bug jdbc

Difficulty 4/5 3-5 days Newbie friendliness 68/100

ClickHouse/clickhouse-java#3127 · 1 comment · Opened Sep 11, 2026
[jdbc-v2] ResultSet label getters return null/0 for an unknown column label instead of throwing SQLException Open

area:jdbc-read bug jdbc-v2

ClickHouse/clickhouse-java#3125 · 1 assignee · Opened Sep 11, 2026
jdbc-v2: JavaCC grammar has no RECURSIVE token, so every recursive CTE logs a parse-failure WARN Open

area:sql-parser jdbc-v2

ClickHouse/clickhouse-java#3122 · 1 comment · 1 assignee · Opened Sep 11, 2026
[client-v2,jdbc-v2] Remove default socket snd/rcv buffer Open

ClickHouse/clickhouse-java#3121 · 1 comment · 1 assignee · Opened Sep 10, 2026
[client-v2, jdbc-v2] Client should detect server compression and use proper decompression algorithm Open

Difficulty 4/5 3-5 days Newbie friendliness 50/100

ClickHouse/clickhouse-java#3120 · Opened Sep 10, 2026
[client-v2] Allow QuerySettings in POJO queryAll overloads Open

Difficulty 3/5 1-2 days Newbie friendliness 68/100

ClickHouse/clickhouse-java#3112 · Opened Sep 9, 2026
[examples] Remove old Spring example Open

Difficulty 1/5 Under an hour Newbie friendliness 85/100

ClickHouse/clickhouse-java#3111 · Opened Sep 9, 2026
[client-v1] Every compressed read fails on ClickHouse 26.9+: Lz4InputStream hardcodes the LZ4 magic byte but the server default codec is now ZSTD Open

area:network bug client-v1

Difficulty 4/5 3-5 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#3107 · Opened Sep 8, 2026
[client-v2] Every compressed read fails on ClickHouse 26.9+: response reader is hardcoded to LZ4 but the server default codec is now ZSTD(3) Open

Difficulty 4/5 3-5 days Newbie friendliness 64/100

ClickHouse/clickhouse-java#3105 · 1 comment · Opened Sep 8, 2026
[client-v2] ClickHouseColumn mis-parses a Tuple whose JSON element is not last: later elements are swallowed as JSON parameters Open

area:data-type bug

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

ClickHouse/clickhouse-java#3098 · 1 comment · Opened Sep 3, 2026
client-v2 0.10.0: getTableSchema fails on ClickHouse 26.8 with "Failed to parse column `null` defined by type 'null'" (works on 26.7) Open

bug client-api-v2 jdbc-v2

Difficulty 4/5 3-5 days Newbie friendliness 52/100

ClickHouse/clickhouse-java#3094 · 3 comments · Opened Sep 1, 2026
`socket_keepalive` doesn't work with shaded clickhouse-jdbc Open

bug

Difficulty 3/5 1-2 days Newbie friendliness 52/100

ClickHouse/clickhouse-java#3092 · 4 comments · Opened Sep 1, 2026
[client-v2] getTableSchema and insert concatenate the raw table name into SQL — names needing backquotes cannot be used Open

Difficulty 3/5 1-2 days Newbie friendliness 72/100

ClickHouse/clickhouse-java#3089 · 3 comments · Opened Aug 31, 2026
client-v2: geo columns (Point/Ring/Polygon/...) are misread in the Native format Open

area:data-type bug client-api-v2

Difficulty 4/5 3-5 days Newbie friendliness 68/100

ClickHouse/clickhouse-java#3088 · Opened Aug 31, 2026
jdbc-v2: an INSERT VALUES list holding a literal is routed to the beta RowBinary writer, which silently shifts the bound values Open

area:jdbc-insert area:sql-parser bug jdbc-v2

Difficulty 3/5 1-2 days Newbie friendliness 76/100

ClickHouse/clickhouse-java#3083 · Opened Aug 26, 2026
Progress Header Support Open

Difficulty 3/5 1-2 days Newbie friendliness 55/100

ClickHouse/clickhouse-java#3080 · Opened Aug 26, 2026
[jdbc-v2] Handle query timeout in the middle of stream Open

jdbc-v2

Difficulty 3/5 1-2 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#3077 · 2 comments · Opened Aug 25, 2026
Flaky test: HttpTransportTests.testAccessTokenAuth / testBearerTokenAuth bind a random fixed port and fail with FatalStartupException Open

bug client-api-v2 test

Difficulty 2/5 1-3 hours Newbie friendliness 92/100

ClickHouse/clickhouse-java#3076 · Opened Aug 25, 2026
[client-v2, jdbc-v2] Make execution TIMEOUT error optionally retriable Open

area:general client-api-v2 jdbc-v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#3072 · Opened Aug 24, 2026
[client-v2, jdbc-v2] A caller-supplied FORMAT clause is silently ignored on ClickHouse 26.8+ (X-ClickHouse-Format wins) Open

area:format bug client-api-v2 jdbc-v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#3070 · Opened Aug 20, 2026
clickhouse-data (v1): ClickHouseUtils.skipSingleLineComment jumps to end of query for an empty -- comment, dropping the rest of the SQL Open

area:sql-parser bug client-v1

Difficulty 1/5 1-3 hours Newbie friendliness 92/100

ClickHouse/clickhouse-java#3066 · Opened Aug 19, 2026
Build: any reactor build stopping before 'package' fails with "module not found: com.clickhouse.data" in clickhouse-client java11 module-info Open

area:packaging bug

Difficulty 4/5 3-5 days Newbie friendliness 50/100

ClickHouse/clickhouse-java#3064 · Opened Aug 18, 2026
[client-v2, jdbc-v2] SQLUtils.enquoteLiteral / enquoteIdentifier do not escape backslashes, corrupting or breaking SQL Open

area:general bug client-api-v2 jdbc jdbc-v2

Difficulty 2/5 1-3 hours Newbie friendliness 88/100

ClickHouse/clickhouse-java#3063 · Opened Aug 18, 2026
[r2dbc] Deprecate pre-1.0 support Open

r2dbc

Difficulty 4/5 3-5 days Newbie friendliness 45/100

ClickHouse/clickhouse-java#3062 · Opened Aug 18, 2026
[client-v2] Expose supported configuration options via a public API Open

area:general client-api-v2 enhancement

Difficulty 5/5 Over a week Newbie friendliness 45/100

ClickHouse/clickhouse-java#3059 · 2 comments · 1 reaction · Opened Aug 17, 2026
Flaky test: R2DBCTestKitImplTest.batch intermittently fails with "Connection pool shut down" Open

bug r2dbc test

Difficulty 4/5 3-5 days Newbie friendliness 52/100

ClickHouse/clickhouse-java#3058 · Opened Aug 17, 2026
[client-v2, jdbc-v2] Add MultiPoint type support Open

area:data-type enhancement

ClickHouse/clickhouse-java#3048 · 1 comment · 1 assignee · Opened Aug 12, 2026
Map(K, V) type support issue Open

bug

Difficulty 4/5 3-5 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#3047 · 1 comment · 2 reactions · Opened Aug 11, 2026
Regression in JDBC 0.9.8 when reading Array(Tuple(...)) with named tuple elements. Open

area:data-type area:jdbc-read bug jdbc-v2

Difficulty 3/5 1-2 days Newbie friendliness 52/100

ClickHouse/clickhouse-java#3045 · Opened Aug 6, 2026
[client-v2] serializeArrayData silently writes zero bytes for a wrong-typed Array/geo value and desynchronizes the RowBinary stream Open

area:client-insert area:data-type bug client-api-v2

Difficulty 3/5 1-2 days Newbie friendliness 78/100

ClickHouse/clickhouse-java#3041 · Opened Aug 4, 2026
[client-v2] Compiled POJO setter emits invalid bytecode (VerifyError) when the column type does not match the primitive field type Open

Difficulty 4/5 3-5 days Newbie friendliness 58/100

ClickHouse/clickhouse-java#2999 · Opened Aug 3, 2026
[client-v2/jdbc-v2] getTableSchemaFromQuery wraps SQL verbatim in DESC (...) - trailing comment or semicolon breaks column metadata (code 62) Open

Difficulty 3/5 1-2 days Newbie friendliness 74/100

ClickHouse/clickhouse-java#2982 · Opened Jul 29, 2026
[client-v2] Implement QBit support for Native Format Open

area:data-type

Difficulty 3/5 1-2 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#2980 · Opened Jul 29, 2026
[R2DBC] Cancelled reactive queries leak HTTP connections and exhaust the connection pool Open

area:network bug r2dbc

Difficulty 4/5 3-5 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#2976 · 1 comment · Opened Jul 29, 2026
[client-v2,jdbc-v2] `FORMAT null` support Open

Difficulty 4/5 3-5 days Newbie friendliness 35/100

ClickHouse/clickhouse-java#2963 · Opened Jul 28, 2026
[repo] Create Pre-release workflow or find point where release verification should happen Open

area:general

Difficulty 5/5 Over a week Newbie friendliness 35/100

ClickHouse/clickhouse-java#2961 · 2 comments · 2 reactions · Opened Jul 27, 2026
Add missing `Hash` output format to `ClickHouseFormat` enum (JDBC/DataGrip throws "No enum constant ... Hash") Open

bug client-api-v2 jdbc-v2

Difficulty 1/5 1-3 hours Newbie friendliness 78/100

ClickHouse/clickhouse-java#2957 · 1 comment · Opened Jul 24, 2026
[client-v2,jdbc-v2] Reading Array(Nullable(String)) with BinaryString enabled Open

area:data-type client-api-v2 jdbc-v2

Difficulty 3/5 1-2 days Newbie friendliness 58/100

ClickHouse/clickhouse-java#2953 · Opened Jul 22, 2026
Can users set a fully custom User-Agent that completely replaces the default one, without appending the driver version? Open

area:general client-api-v2 enhancement

Difficulty 3/5 1-2 days Newbie friendliness 68/100

ClickHouse/clickhouse-java#2935 · 1 comment · Opened Jul 17, 2026
[client-v2] FixedString padding Open

area:data-type area:docs client-api-v2

Difficulty 3/5 1-2 days Newbie friendliness 62/100

ClickHouse/clickhouse-java#2929 · Opened Jul 15, 2026
[client-v2] POJO serialization: Skipped fields still consume memory Open

client-api-v2 performance

Difficulty 4/5 3-5 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#2928 · Opened Jul 15, 2026
[jdbc-v2, client-v2] Document using client with SAML/OAuth Open

Difficulty 3/5 1-2 days Newbie friendliness 58/100

ClickHouse/clickhouse-java#2913 · Opened Jul 7, 2026
[jdbc-v2] `DataLakeCatalog` is not present in `getSchemas()` result or avoid using `system.*` where possible. Open

area:jdbc-metadata bug jdbc-v2

Difficulty 4/5 3-5 days Newbie friendliness 48/100

ClickHouse/clickhouse-java#2907 · 2 comments · Opened Jul 2, 2026
[client-v2] readVariant discards the active type discriminant — colliding Variant alternatives are indistinguishable Open

area:data-type bug client-api-v2

Difficulty 4/5 3-5 days Newbie friendliness 45/100

ClickHouse/clickhouse-java#2901 · 1 comment · Opened Jun 28, 2026
client-v1 (clickhouse-data): "Duplicate key" IllegalStateException on result sets with duplicate column names (0.9.8) Open

bug client-v1 wontfix

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

ClickHouse/clickhouse-java#2895 · 1 comment · Opened Jun 25, 2026

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