sql: simplifiy tracking of injected txn retry errors

[rafiss]

Rather than using the txn epoch, we can just track how many errors were
injected. This lets us have a bit more control over how many errors to
inject, without having to rely on how the KV layer handles different
types of transaction retries.

informs: #100145
split off from: #107044
Release note: None

[blathers-crl]

It looks like your PR touches production code but doesn't add or edit any test code. Did you consider adding tests to your PR?

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[cockroach-teamcity]

This change is 

[nvanbenschoten]

Reviewed 1 of 1 files at r1, 3 of 3 files at r2, all commit messages.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @michae2 and @rafiss)

---

pkg/sql/txn_state.go line 189 at r2 (raw file):

	// Reset state vars to defaults.
	ts.sqlTimestamp = sqlTimestamp
	ts.isHistorical = false

Double checking that we don't need to reset injectedTxnRetryCounter here.

[rafiss]

Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @michae2 and @nvanbenschoten)

---

pkg/sql/txn_state.go line 189 at r2 (raw file):

Previously, nvanbenschoten (Nathan VanBenschoten) wrote…

Double checking that we don't need to reset injectedTxnRetryCounter here.

hm, well it could. the reason i did not is because i moved the counter into extraTxnState. but after reading this more closely, i think it makes more sense to keep it in this txnState instead. extraTxnState is meant for things that need to be passed into the internal executor, which we don't actually want for this counter

[rafiss]

tftr!

bors r+

[craig]

This PR was included in a batch that was canceled, it will be automatically retried

[craig]

Build succeeded:

• Bazel Essential CI (Cockroach)