[Fdo-trac] [fdo-trac] #893: MySQL Provider upgrade to use ST_INTERSECTS()

[FDO]

#893: MySQL Provider upgrade to use ST_INTERSECTS()
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 Reporter:  kshippey        |        Owner:  jng
     Type:  enhancement     |       Status:  closed
 Priority:  major           |    Milestone:  3.8.0
Component:  MySQL Provider  |      Version:  3.8.0
 Severity:  3               |   Resolution:  fixed
 Keywords:  ST_INTERSECTS   |  External ID:
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Comment (by kshippey):

 A pseudo-bug on this MySQL Provider update:

 It appears that before querying against the spatial operation, there is an
 initial query to obtain the SRID for all rows of the table. For large
 MySQL spatial tables, this initial SRID query is a very expensive
 operation that ultimately renders it unusable above a certain threshold,
 perhaps 1 million rows, due to timeout. Unfortunately for use on a dynamic
 MySQL table, that is not a very large threshold. Even for smaller tables
 this is an unnecessary query without any applied LIMIT.

 One improvement might be to call the GetSRID() with a LIMIT to just one
 single row, and assume the rest of the table follows suit. Once past that
 SRID call, the spatial index in MySQL is very effective at returning
 relevant results even on a very large dataset.

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Ticket URL: <https://trac.osgeo.org/fdo/ticket/893#comment:4>
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