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https://issues.apache.org/jira/browse/GROOVY-12371?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18112006#comment-18112006
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ASF GitHub Bot commented on GROOVY-12371:
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paulk-asert opened a new pull request, #2895:
URL: https://github.com/apache/groovy/pull/2895
The prepared-statement cache was an unbounded HashMap keyed on the SQL text,
mutated from getAbstractStatement without synchronization. Two problems
followed. It grew without limit whenever the text varied rather than the
parameters — an inList expands to a different placeholder count per list size,
so a caller sizing the list mints a distinct cached statement each time, held
open until the Sql is closed. And a shared Sql using the cache from more than
one thread could corrupt the map.
The cache is now a synchronized, access-ordered LinkedHashMap that evicts
the least recently used statement past a cap, closing it as it goes so a
bounded cache does not leak the cursor it drops. The cap is statementCacheSize,
default 256, settable and overridable with the groovy.sql.statement.cache.size
system property; 0 or less keeps the old unbounded behaviour for anyone who
relied on it.
Statement creation stays outside the lock — only the get-then-put is
synchronized — so preparing a statement does not serialize other callers, and a
create race keeps the first result and closes the loser rather than leaking it.
One consequence to note: with a shared Sql caching across threads, a bound
below the working set can now evict and close a statement another thread is
about to reuse. A single Sql is typically used serially or per connection;
where it is shared, size the cache above the working set (or leave it
unbounded). Default 256 is generous enough that ordinary use never evicts.
> SQL: bound the statement cache and make it thread-safe
> ------------------------------------------------------
>
> Key: GROOVY-12371
> URL: https://issues.apache.org/jira/browse/GROOVY-12371
> Project: Groovy
> Issue Type: Task
> Reporter: Paul King
> Assignee: Paul King
> Priority: Major
>
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