Do not enable read_uncommitted by default

[masih]

The PRAGMA for 3 databases across lotus repo enable uncommitted reads:

lotus/chain/ethhashlookup/eth_transaction_hash_lookup.go

Line 25 in 395cdd7

"PRAGMA read_uncommitted = ON",

lotus/chain/events/filter/index.go

Line 32 in 6bc04c8

"PRAGMA read_uncommitted = ON",

lotus/chain/events/filter/index.go

Line 32 in 6bc04c8

"PRAGMA read_uncommitted = ON",

This can have some performance gain but will cause all sorts of problems, specially in db interactions that require ACID properties where data consistency matters. Based on a quick look we do care about data consistency across all three places listed above. Therefore, I recommend against performing dirty reads.

[snissn]

I think we can close this - https://github.com/filecoin-project/lotus/pull/12090/files#diff-fe5e47a357d5465c3a2b1002977a53ad7c0990f76da22137417723577b87b19eL32 @rvagg made the change in pull #12090

[masih]

That PR only updates events db pragma. right?

[rvagg]

yeah, only events sorry, we can follow up with the others as a separate PR

[BigLep]

2024-06-18 triage note: @rvagg we wanted to confirm that #12098 will address this issue.

[rvagg]

yes, it will, they'll all have the same pragma and read_uncommitted is gone