workload: add pgx-based SQLRunner, use it in KV

[RaduBerinde]

SQLRunner is a common facility for issuing SQL queries through pgx.
It supports multiple issuing methods, specified by the --method
flag:

• prepare: each statement is prepared once per session and then
  reused.
• noprepare: each statement is executed directly (which internally
  is equivalent to preparing and executing each statement
  separately).
• simple: parameters are formatted as text and replaced in the query
  before it is issued.

KV is switched to use the new runner. The default prepare method
should be similar to the old code (except that we go through pgx).

Benchmark numbers (ops/s for kv80, single node GCE worker):

• before: 30990 (541 stddev)
• prepare (default): 31478 (331 stddev)
• noprepare: 25506 (530 stddev)
• simple: 29187 (599 stddev)

Release note: None

[cockroach-teamcity]

This change is 

[cockroach-teamcity]

This change is 

[RaduBerinde]

Full benchmark results (including a comparison with a gosql version of SQLRunner): https://docs.google.com/spreadsheets/d/1I028xgdHM9nqydMG3KblfzvZlXGfLRBXrC3xeqiilG8/edit?usp=sharing

[RaduBerinde]

Full benchmark results (including a comparison with a gosql version of SQLRunner): https://docs.google.com/spreadsheets/d/1I028xgdHM9nqydMG3KblfzvZlXGfLRBXrC3xeqiilG8/edit?usp=sharing

[danhhz]

Reviewable status: complete! 0 of 0 LGTMs obtained

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pkg/workload/pgx_helpers.go, line 83 at r1 (raw file):

// Get returns one of the pools, in round-robin manner.
func (m *MultiConnPool) Get() *pgx.ConnPool {

Have you thought about how this will play with the partition affinity in tpcc? Keep the existing logic but with one MultiConnPool per url perhaps?

[RaduBerinde]

Reviewable status: complete! 0 of 0 LGTMs obtained

---

pkg/workload/pgx_helpers.go, line 83 at r1 (raw file):

Previously, danhhz (Daniel Harrison) wrote…

Have you thought about how this will play with the partition affinity in tpcc? Keep the existing logic but with one MultiConnPool per url perhaps?

Yeah, that should work fine.

[danhhz]

Reviewable status: complete! 0 of 0 LGTMs obtained (and 1 stale)

[nvanbenschoten]

Reviewable status: complete! 0 of 0 LGTMs obtained (and 2 stale)

[RaduBerinde]

bors r+

[RaduBerinde]

bors r+

[craig]

Build succeeded

• GitHub CI (Cockroach)

[craig]

Build succeeded

• GitHub CI (Cockroach)