Improving object allocation for (positional) parameter binding

[mdonkers]

Summary

I noticed very high object allocation count with the ClickHouse Go client in our code. While with binding the parameters to a String this is logical to some extend, I found some easy improvements:

1. Mis-use of the strings.NewReplacer, as this instance is meant to be re-used but a new instance was created all the time
2. Replacement of positional arguments in the query string, for which not really a regex is needed. Specifically to find \? cases, two regex replacements were nested, creating a temporary string instance that shouldn't be needed. So I changed to code to a 'simple' loop that copies byte sequences.

Original object allocation:

Allocations after just changing strings.NewReplacer to be called once:

Final result:

(of course above numbers are case specific, but for our instance this meant going from being responsible for 70% of object allocations to around 30%)

Checklist

Delete items not relevant to your PR:

• Unit and integration tests covering the common scenarios were added
• A human-readable description of the changes was provided to include in CHANGELOG
• For significant changes, documentation in https://github.com/ClickHouse/clickhouse-docs was updated with further explanations or tutorials

[jkaflik]

@mdonkers this is great! Thanks. Please remove changes to CHANGELOG.md. It's generated automatically. We have quite unstable runners nowadays - i will take a look.

[mdonkers]

@mdonkers this is great! Thanks. Please remove changes to CHANGELOG.md. It's generated automatically. We have quite unstable runners nowadays - i will take a look.

Reverted the changelog and squashed the commits to only have the actual changes in there.