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Asked: 2026-05-23T02:50:27+00:00

Dear fellow developer, for some reason updates for 1720 records takes around 15 seconds

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Dear fellow developer, for some reason updates for 1720 records takes around 15 seconds when on SSD disk (especially when having trim enabled).

I have tweaked the sqlite settings using the following document (which works well)
http://web.utk.edu/~jplyon/sqlite/SQLite_optimization_FAQ.html

I have the following PRAGMA’s set to optimize performance and I DO use transactions around the complete set of updates.

sqlite3_exec(database, "PRAGMA cache_size=500000;", nil, nil, nil);
sqlite3_exec(database, "PRAGMA synchronous=OFF", nil, nil, nil);
sqlite3_exec(database, "PRAGMA count_changes=OFF", nil, nil, nil);
sqlite3_exec(database, "PRAGMA temp_store=MEMORY", nil, nil, nil);

It seems the SSD is doing too much (like deleting blocks and such) which makes it block for 15 seconds for just 1720 simple records update.

Weirdly enough: inserting 2500 records is almost instant.
Can you help me and give me some pointers how to fix this?

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1 Answer

  1. Editorial Team

    I found the answer by doing some good old testing and trying out.
    It seems that sqlite will freeze on SSDs with TRIM when doing a lot of single UPDATE statements after each other in a transaction.

    I’ve changed the code now:
    a) prepare a command and reuse that command for all the to-be updated records.
    b) COMMIT and BEGIN a new transaction every 1500 records

    this seems to have fixed the freeze in sqlite. So in short: reuse the prepared sql statement and make sure the transaction doesn’t get too large.

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