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08612f45a0
If the lower left and upper right corners of a cube are the same, set a flag in the cube header, and only store one copy of the coordinates. That cuts the on-disk size into half for the common case that the cube datatype is used to represent points rather than boxes. The new format is backwards-compatible with the old one, so pg_upgrade still works. However, to get the space savings, the data needs to be rewritten. A simple VACUUM FULL or REINDEX is not enough, as the old Datums will just be moved to the new heap/index as is. A pg_dump and reload, or something similar like casting to text and back, will do the trick. This patch deliberately doesn't update all the alternative expected output files, as I don't have access to machines that produce those outputs. I'm not sure if they are still relevant, but if they are, the buildfarm will tell us and produce the diff required to fix it. If none of the buildfarm animals need them, they should be removed altogether. Patch by Stas Kelvich.
50 lines
1.6 KiB
C
50 lines
1.6 KiB
C
/* contrib/cube/cubedata.h */
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#define CUBE_MAX_DIM (100)
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typedef struct NDBOX
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{
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/* varlena header (do not touch directly!) */
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int32 vl_len_;
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/*----------
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* Header contains info about NDBOX. For binary compatibility with old
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* versions, it is defined as "unsigned int".
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*
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* Following information is stored:
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*
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* bits 0-7 : number of cube dimensions;
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* bits 8-30 : unused, initialize to zero;
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* bit 31 : point flag. If set, the upper right coordinates are not
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* stored, and are implicitly the same as the lower left
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* coordinates.
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*----------
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*/
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unsigned int header;
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/*
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* Variable length array. The lower left coordinates for each dimension
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* come first, followed by upper right coordinates unless the point flag
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* is set.
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*/
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double x[1];
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} NDBOX;
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#define POINT_BIT 0x80000000
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#define DIM_MASK 0x7fffffff
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#define IS_POINT(cube) ( ((cube)->header & POINT_BIT) != 0 )
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#define SET_POINT_BIT(cube) ( (cube)->header |= POINT_BIT )
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#define DIM(cube) ( (cube)->header & DIM_MASK )
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#define SET_DIM(cube, _dim) ( (cube)->header = ((cube)->header & ~DIM_MASK) | (_dim) )
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#define LL_COORD(cube, i) ( (cube)->x[i] )
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#define UR_COORD(cube, i) ( IS_POINT(cube) ? (cube)->x[i] : (cube)->x[(i) + DIM(cube)] )
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#define POINT_SIZE(_dim) (offsetof(NDBOX, x[0]) + sizeof(double)*(_dim))
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#define CUBE_SIZE(_dim) (offsetof(NDBOX, x[0]) + sizeof(double)*(_dim)*2)
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#define DatumGetNDBOX(x) ((NDBOX*)DatumGetPointer(x))
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#define PG_GETARG_NDBOX(x) DatumGetNDBOX( PG_DETOAST_DATUM(PG_GETARG_DATUM(x)) )
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#define PG_RETURN_NDBOX(x) PG_RETURN_POINTER(x)
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