perf: CoreStatement uses optimize regex for generated key matches #1080
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While profiling some software that makes heavy use of prepared statements and SQLite, I noticed that each call to `java.sql.Connection#prepareStatement(java.lang.String)` ended up compiling a regex pattern as part of `org.sqlite.core.CoreStatement.<init>(SQLiteConnection)` construction. This appears to be a recent addition as part of xerial#1056 with example call trace showing up as over 75% of total allocations in JFR: <img width="1135" alt="image" src="https://github.com/xerial/sqlite-jdbc/assets/54594/f5b5d452-f21c-4bf0-a8d6-beb8f5640321"> Because JDK `Pattern` instances are immutable and thread-safe, we can compile the regex on `CoreStatement` class load to a static field for reuse, and adjust the regex to avoid additional possible allocations from trimming and converting the SQL to lower case, as well as use non-capturing groups to avoid `Pattern#matcher` allocating the `int[]` arrays associated with capture groups.
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thanks a lot for the PR ! |
gotson
changed the title
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While profiling some software that makes heavy use of prepared statements and SQLite, I noticed that each call to
java.sql.Connection#prepareStatement(java.lang.String)ended up compiling a regex pattern as part oforg.sqlite.core.CoreStatement.<init>(SQLiteConnection)construction. This appears to be a recent addition as part of #1056 with example call trace showing up as over 75% of total allocations in JFR:Because JDK
Patterninstances are immutable and thread-safe, we can compile the regex onCoreStatementclass load to a static field for reuse, and adjust the regex to avoid additional possible allocations from trimming and converting the SQL to lower case, as well as use non-capturing groups to avoidPattern#matcherallocating theint[]arrays associated with capture groups.