{"push_id":761296412,"size":1,"distinct_size":1,"ref":"refs/heads/dense_block_size","head":"ff2ad1ccb3eaf7619151acb413a3bc0a162c786d","before":"2d4e7e5f48204f391c197e7c5580688230a28f4c","commits":[{"sha":"ff2ad1ccb3eaf7619151acb413a3bc0a162c786d","author":{"email":"79b28d77f769894d4d82a0d46b7298f97cd55d01@mac.com","name":"Paul Norman"},"message":"Increase dense block size from 1k to 8k nodes\n\nThe dense cache has a fixed memory cost which is associated with\nthe number of blocks needed. Increase the block size reduces the\nnumber of blocks, resulting in reduced memory usage. For this change\non modern hardware it is a decrease from 1GB to 128MB. Large blocks\nare less efficient than small ones, but it turns out that this does\nnot matter for planet imports, where the efficiency change is small\nand memory usage is actually slightly reduced, or for small imports,\nwhere the fixed cost change overwhelms anything else.\n\nOn large but not planet sized extracts (e.g. Europe) memory usage\nis slightly increased, by about 450MB, while the cache in total\nconsumes about 18GB.\n\nChanging the cache size did not have a measurable impact of\nperformance in testing.\n\nFixes #439","distinct":true,"url":"https://api.github.com/repos/pnorman/osm2pgsql/commits/ff2ad1ccb3eaf7619151acb413a3bc0a162c786d"}]}