perf(bigquery): [T1-18] short-circuit duplicate retry evaluation and pre-compile regexes in BigQueryRetryAlgorithm

[lqiu96]

Summary & Bottleneck

Every RPC invoked through BigQueryRetryHelper.runWithRetries calls BigQueryRetryAlgorithm.shouldRetry(Throwable, ResponseT, TimedAttemptSettings) (java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/BigQueryRetryAlgorithm.java:L82-L90). On every retry check (including the initial createFirstAttempt() call where nextAttemptSettings == null on every single RPC), shouldRetry evaluated shouldRetryBasedOnResult(previousThrowable, previousResponse) and shouldRetryBasedOnBigQueryRetryConfig(previousThrowable, previousResponse, bigQueryRetryConfig) before checking nextAttemptSettings != null, AND then evaluated both predicates a second time inside the return statement. Furthermore, matchRegEx (BigQueryRetryAlgorithm.java:L164-L176) called Pattern.compile(regEx, Pattern.CASE_INSENSITIVE) on every retry evaluation, matchErrorMessages (BigQueryRetryAlgorithm.java:L149-L162) called .toLowerCase() on every configured error message string on every retry check, and BigQueryImpl.create(JobInfo, JobOption...) (java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/BigQueryImpl.java:L458) compiled Pattern.compile("Already Exists: Job (.+):(.+)\\.(.+)", Pattern.CASE_INSENSITIVE) inline.

Changes

• Short-circuit BigQueryRetryAlgorithm.shouldRetry (java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/BigQueryRetryAlgorithm.java) to return false immediately when nextAttemptSettings == null and evaluate the retry predicates once instead of twice.
• Pre-compute ImmutableSet<String> lowerCaseRetriableErrorMessages and ImmutableList<Pattern> compiledRetriableRegExes inside BigQueryRetryConfig (java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/BigQueryRetryConfig.java) at config construction time, and use them in BigQueryRetryAlgorithm.matchErrorMessages and BigQueryRetryAlgorithm.matchRegEx.
• Hoist ALREADY_EXISTS_JOB_PATTERN as a private static final Pattern constant in BigQueryImpl (java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/BigQueryImpl.java).

Expected Impact

• Complexity / Scaling: $O(\text{RPCs})$ and $O(\text{retry attempts})$.
• Eliminates redundant predicate evaluation on the initial attempt of every RPC and halves retry evaluation overhead on failed attempts.
• Eliminates per-attempt Pattern.compile(...) and per-config-entry String.toLowerCase(...) allocations.

Verification

• Verified with mvn test -pl java-bigquery/google-cloud-bigquery -Dtest=BigQueryImplTest -Dclirr.skip=true -Denforcer.skip=true -Dcheckstyle.skip=true (151 tests passing).