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| author | dgrogan@chromium.org <dgrogan@chromium.org@62dab493-f737-651d-591e-8d6aee1b9529> | 2011-04-19 23:01:25 +0000 |
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| committer | dgrogan@chromium.org <dgrogan@chromium.org@62dab493-f737-651d-591e-8d6aee1b9529> | 2011-04-19 23:01:25 +0000 |
| commit | b743906eeabc925f3e824d91a9747012bf249e2f (patch) | |
| tree | e7cb4f854196c43045756469627920e4e7b146c1 /doc/table_format.txt | |
| parent | b409afe968b6917574ec08e02c4bf6e6f722e3ca (diff) | |
| download | leveldb-b743906eeabc925f3e824d91a9747012bf249e2f.tar.gz | |
Revision created by MOE tool push_codebase.
MOE_MIGRATION=
git-svn-id: https://leveldb.googlecode.com/svn/trunk@22 62dab493-f737-651d-591e-8d6aee1b9529
Diffstat (limited to 'doc/table_format.txt')
| -rw-r--r-- | doc/table_format.txt | 61 |
1 files changed, 0 insertions, 61 deletions
diff --git a/doc/table_format.txt b/doc/table_format.txt deleted file mode 100644 index ad5aa4b..0000000 --- a/doc/table_format.txt +++ /dev/null @@ -1,61 +0,0 @@ -File format -=========== - - <beginning_of_file> - [data block 1] - [data block 2] - ... - [data block N] - [meta block 1] - ... - [meta block K] - [metaindex block] - [index block] - [Footer] (fixed size; starts at file_size - sizeof(Footer)) - <end_of_file> - -The file contains internal pointers. Each such pointer is called -a BlockHandle and contains the following information: - offset: varint64 - size: varint64 - -(1) The sequence of key/value pairs in the file are stored in sorted -order and partitioned into a sequence of data blocks. These blocks -come one after another at the beginning of the file. Each data block -is formatted according to the code in block_builder.cc, and then -optionally compressed. - -(2) After the data blocks we store a bunch of meta blocks. The -supported meta block types are described below. More meta block types -may be added in the future. Each meta block is again formatted using -block_builder.cc and then optionally compressed. - -(3) A "metaindex" block. It contains one entry for every other meta -block where the key is the name of the meta block and the value is a -BlockHandle pointing to that meta block. - -(4) An "index" block. This block contains one entry per data block, -where the key is a string >= last key in that data block and before -the first key in the successive data block. The value is the -BlockHandle for the data block. - -(6) At the very end of the file is a fixed length footer that contains -the BlockHandle of the metaindex and index blocks as well as a magic number. - metaindex_handle: char[p]; // Block handle for metaindex - index_handle: char[q]; // Block handle for index - padding: char[40-p-q]; // 0 bytes to make fixed length - // (40==2*BlockHandle::kMaxEncodedLength) - magic: fixed64; // == 0xdb4775248b80fb57 - -"stats" Meta Block ------------------- - -This meta block contains a bunch of stats. The key is the name -of the statistic. The value contains the statistic. -TODO(postrelease): record following stats. - data size - index size - key size (uncompressed) - value size (uncompressed) - number of entries - number of data blocks |