feat: iavl, db & disk stats logging

[iproudhon]

Added iavl, db & disk stats logging when IAVL_DEV environment variable is set to the device name to check the disk io activity.

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[codecov]

Codecov Report

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The diff coverage is n/a.

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[egonspace]

.

[egonspace]

Wouldn't it affect performance to open and parse the file every commit? How about to create a config for turning it off and turning it on?

[iproudhon]

Wouldn't it affect performance to open and parse the file every commit? How about to create a config for turning it off and turning it on?

It's just string pointer comparisons. If it's uninitialized, i.e. logIoDev == nil, then it checks environment variable once and only once. It's very likely it's disabled all the time, that's why "if logIoDev == &logIoDevNop" is the first line, so that it's just one if condition check most of the cases.

if logIoDev == &logIoDevNop {
// disabled
} else if logIoDev == nil {
// uninitialized, check env. var.
} else {
// enabled, *logIoDev is set to device name to collect data
}

[egonspace]

It only works when IAVL_DEV is set. I missed this.

[egonspace]

LGTM