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33 lines
1.3 KiB
Text
33 lines
1.3 KiB
Text
src/timezone/README
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Timezone
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========
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This is a PostgreSQL adapted version of the timezone library from:
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ftp://elsie.nci.nih.gov/pub/tzcode*.tar.gz
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The code is currently synced with release 2010c. There are many cosmetic
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(and not so cosmetic) differences from the original tzcode library, but
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diffs in the upstream version should usually be propagated to our version.
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The data files under data/ are an exact copy of the latest data set from:
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ftp://elsie.nci.nih.gov/pub/tzdata*.tar.gz
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Since time zone rules change frequently in some parts of the world,
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we should endeavor to update the data files before each PostgreSQL
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release.
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At each update, we should check if time zone offsets have changed.
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Just search for the current or previous year and see what has changed.
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Sometimes a country changes its time zone offsets, for example Georgia
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in 2004. Just grepping in the zic database files for 2004 is enough to
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spot such a change. Then the files under tznames/ should be updated.
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When there has been a new release of Windows (probably including Service
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Packs), the list of matching timezones need to be updated. Run the
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script in src/tools/win32tzlist.pl on a Windows machine running this new
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release and apply any new timezones that it detects. Never remove any
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mappings in case they are removed in Windows, since we still need to
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match properly on the old version.
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