On 2/14/2017 7:33 AM, Jens-Heiner Rechtien wrote:
please consider the attached dump of a sqlite3 database and the
following - admittedly nonsensical, don't ask - query over a restored
version of the database:
*SELECT count(*) FROM spacefavorite, album_asset, albums,
assetProfileLinks, avatarCacheReferences, cacheReferences, comment,
conflicts, coreInfo, coreMD5, errors, flags, importSource,
missingBinariesOnOz, profileRegistration, quota_exceeded,
renditionRevisions, space, space_album LIMIT 1;**
*
You are asking SQLite to count an enormous number of rows, so don't be
surprised if that takes an enormous amount of time.
You have a cross-join of 19 tables. Even if each one contains just 2
rows, that's 2^19 ~ 500K rows to work through. And it grows
exponentially from there.
--
Igor Tandetnik
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