From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [tarantool-patches] Re: [PATCH v5 4/4] box: introduce multikey indexes in memtx References: <20190506154603.txsxk2hsyshdqtdb@esperanza> From: Kirill Shcherbatov Message-ID: <88b86a7c-686d-30ac-fe75-f892381e96a4@tarantool.org> Date: Mon, 6 May 2019 19:35:10 +0300 MIME-Version: 1.0 In-Reply-To: <20190506154603.txsxk2hsyshdqtdb@esperanza> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit To: tarantool-patches@freelists.org, Vladimir Davydov List-ID: > > How's it going to work in case the field map stored in a tuple is > greater than field_map_size? > > I think we should calculate the real size of the field map here > in case the format allows multikey indexes. Consider this diff (not on branch yet): diff --git a/src/box/field_map.c b/src/box/field_map.c index 5d25e3032..a917d4a25 100644 --- a/src/box/field_map.c +++ b/src/box/field_map.c @@ -105,12 +105,28 @@ field_map_build(struct field_map_builder *builder, char *buffer) struct field_map_builder_slot_extent *extent = builder->slots[i].extent; /** Retrive memory for the extent. */ - uint32_t sz = sizeof(struct field_map_builder_slot_extent) + - extent->size * sizeof(uint32_t); field_map[i] = (uint32_t)((char *)extent_wptr - (char *)field_map); - memcpy(extent_wptr, extent, sz); - extent_wptr += sz; + *(uint32_t *)extent_wptr = extent->size; + uint32_t extent_offset_sz = extent->size * sizeof(uint32_t); + memcpy(&((uint32_t *) extent_wptr)[1], extent->offset, + extent_offset_sz); + extent_wptr += sizeof(uint32_t) + extent_offset_sz; } assert(extent_wptr == buffer + builder->extents_size); } + +uint32_t +field_map_get_size(const uint32_t *field_map, uint32_t format_field_map_sz) +{ + uint32_t total = format_field_map_sz; + int32_t field_map_items = format_field_map_sz / sizeof(uint32_t); + for (int32_t slot = -1; slot >= -field_map_items; slot--) { + if ((int32_t)field_map[slot] >= 0) + continue; + uint32_t *extent = (uint32_t *)((char *)field_map + + (int32_t)field_map[slot]); + total += (1 + extent[0]) * sizeof(uint32_t); + } + return total; +} diff --git a/src/box/field_map.h b/src/box/field_map.h index 0fd35c3e1..78c96e4f7 100644 --- a/src/box/field_map.h +++ b/src/box/field_map.h @@ -163,6 +163,19 @@ field_map_get_offset(const uint32_t *field_map, int32_t offset_slot, return offset; } +/** + * Get size of the tuple field_map using + * field_map pointer and format root field_map size. + * + * In case of multikey indexes the real field_map size may be + * greater than the size of format root field_map. To calculate + * the total size of the field_map extentions, routine relies + * on the fact that all field_map slots that has an extention + * use negative offset as a marker. + */ +uint32_t +field_map_get_size(const uint32_t *field_map, uint32_t format_field_map_sz); + /** * Initialize field_map_builder. * diff --git a/src/box/memtx_engine.c b/src/box/memtx_engine.c index 65e8804a4..ab4913035 100644 --- a/src/box/memtx_engine.c +++ b/src/box/memtx_engine.c @@ -1180,6 +1180,8 @@ memtx_tuple_new(struct tuple_format *format, const char *data, const char *end) char *raw = (char *) tuple + tuple->data_offset; field_map_build(&builder, raw - field_map_size); memcpy(raw, data, tuple_len); + assert(field_map_get_size((uint32_t *)raw, + format->field_map_size) == field_map_size); say_debug("%s(%zu) = %p", __func__, tuple_len, memtx_tuple); end: region_truncate(region, region_svp); @@ -1192,8 +1194,9 @@ memtx_tuple_delete(struct tuple_format *format, struct tuple *tuple) struct memtx_engine *memtx = (struct memtx_engine *)format->engine; say_debug("%s(%p)", __func__, tuple); assert(tuple->refs == 0); - size_t total = sizeof(struct memtx_tuple) + format->field_map_size + - tuple->bsize; + const uint32_t *field_map = tuple_field_map(tuple); + size_t total = sizeof(struct memtx_tuple) + tuple->bsize + + field_map_get_size(field_map, format->field_map_size); tuple_format_unref(format); struct memtx_tuple *memtx_tuple = container_of(tuple, struct memtx_tuple, base);