Apply SQL_BODY_MAX_LENGTH to ClickHouse JDBC plugin span tags

[daguimu]

Problem

ClickHouseStatementTracingWrapper (in clickhouse-0.3.1-plugin) and ClickHousePrepareStatementTracing (in clickhouse-0.3.2.x-plugin) record the SQL string directly into the DB_STATEMENT span tag:

Tags.DB_STATEMENT.set(span, sql);

Every other JDBC plugin in apm-sdk-plugin/ routes the same tag through SqlBodyUtil#limitSqlBodySize, which truncates the value to JDBCPluginConfig.Plugin.JDBC.SQL_BODY_MAX_LENGTH and appends .... As a result, an operator who lowers SQL_BODY_MAX_LENGTH to control trace payload size still sees the full unbounded SQL emitted by the ClickHouse plugins.

Root Cause

The two ClickHouse interceptors miss the SqlBodyUtil#limitSqlBodySize call that the rest of the JDBC plugin family uses. The configuration option exists and works for every other JDBC dialect; only ClickHouse does not honour it.

Fix

Wrap the SQL with SqlBodyUtil#limitSqlBodySize in both interceptors. SqlBodyUtil already handles the negative-limit sentinel that disables truncation, so behaviour is unchanged for users who left the default in place but rely on the disable-truncation override.

Add a CHANGES.md entry under "Bug Fixes".

Tests Added

Change point	Test
ClickHouseStatementTracingWrapper.of truncates when SQL exceeds the configured limit	ClickHouseStatementTracingWrapperTest#longSqlIsTruncatedToConfiguredLimit — sets the limit to 16, asserts the recorded tag is the first 16 characters plus ...
Same wrapper passes short SQL through unchanged	ClickHouseStatementTracingWrapperTest#shortSqlIsRecordedAsIs — sets the limit to 2048, asserts the recorded tag equals the original SQL
Negative limit disables truncation	ClickHouseStatementTracingWrapperTest#negativeLimitDisablesTruncation — sets the limit to -1 with a 3KB SQL, asserts the full SQL is recorded
Same three semantics for ClickHousePrepareStatementTracing.of	ClickHousePrepareStatementTracingTest#shortSqlIsRecordedAsIs, #longSqlIsTruncatedToConfiguredLimit, #negativeLimitDisablesTruncation

mvn -pl apm-sniffer/apm-sdk-plugin/clickhouse-0.3.1-plugin,apm-sniffer/apm-sdk-plugin/clickhouse-0.3.2.x-plugin -am test — all 31 tests in clickhouse-0.3.2.x-plugin and 6 tests in clickhouse-0.3.1-plugin pass locally.

Each test restores JDBCPluginConfig.Plugin.JDBC.SQL_BODY_MAX_LENGTH in @After to keep test ordering safe.

Impact

• Users who configured plugin.jdbc.sql_body_max_length will now see the same truncation behaviour for ClickHouse spans that they already get for MySQL / PostgreSQL / H2 / SQL Server / ...
• Default users (no explicit limit) keep the same payload size as before, since the default limit is large.
• No public API changes.