sync_local: Re-use prepared statements #79
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simolus3
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simolus3
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This keeps prepared statements around for the last table, to avoid preparing a new statement for every row that we insert/delete.
I did not fully confirm, but I expect that the way the query plan is structured that the rows would typically be processed one table at a time, making it efficient to only keep the tables for the last query. It is not an issue if the order is different - we may just lose a little of the performance benefits here.
In my tests on native desktop with an in-memory db, this reduced the overall sync_local duration by around 25% (2786ms -> 2075ms for 500k rows). When taking into account filesystem overhead, the impact will be a little less, but still significant.