perf(spanner): use StringBuilder for generating RequestId#12809
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perf(spanner): use StringBuilder for generating RequestId#12809
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Use a StringBuilder instead of String.format(..) to generate the header value of a RequestId. This significantly reduces the CPU time needed. Generating the header value for 10mio RequestIds using the new/old implementation take: - Old: 2750ms - New: 203ms
sakthivelmanii
approved these changes
Apr 15, 2026
rahul2393
approved these changes
Apr 15, 2026
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This pull request optimizes the generation of Spanner request IDs by pre-calculating static and instance-specific prefixes and replacing String.format with StringBuilder in getHeaderValue and toString. The review feedback suggests using a more precise initial capacity for the StringBuilder instances, calculated from the instancePrefix length, to avoid potential internal array resizes in high-throughput paths.
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Use a StringBuilder instead of String.format(..) to generate the header value of a RequestId. This significantly reduces the CPU time needed. Generating the header value for 10mio RequestIds using the new/old implementation take: