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None of what you said addresses the issue that I (or they) are talking about. On Postgres an update requires a rewrite of every index of the row. On MySQL it
by Negitivefrags 10y ago
None of what you said addresses the issue that I (or they) are talking about.
On Postgres an update requires a rewrite of every index of the row.
On MySQL it only requires an update of the indexes that were touched by the update.
If you have a table with 10 indexes then this means doing 10 extra writes physically to the disk.
- dialogbox 10y agoAs I know, not every updates rewrite indexes in PG. It has single page clean up and HOT (heap only tuple) update optimization. Please refer to 64~ page of https://momjian.us/main/writings/pgsql/mvcc.pdf https://momjian.us/main/writings/pgsql/mvcc.pdf.
- continuational 10y ago10 indexes on one table seems a bit much. It sounds like a table that hasn't been normalized.