Comment by Jweb_Guru

Your smaller points don't make much sense to me... PG doesn't have a REDO log, that's just not the way it's architected. If you mean WAL, a patch went out in 9.4 to prevent updates to a page from rewriting more than necessary, so they're not doing full-page writes each time. Clustered index also makes inserts slower--it's again not a straight win for MySQL (and what query patterns other than range scans of the PK does it make cheaper?). Finally, while obviously it's not the same as InnoDB compression, TOAST does a rather good job in practice, and Postgres's indexes are quite efficiently compressed (especially with new changes in 9.4). I can't speak to (1), but it's not at all clear to me that any of these advantages put MySQL ahead in the long term, and certainly not for all workloads.