| = sstablemetadata |
| |
| Print information about an sstable from the related Statistics.db and |
| Summary.db files to standard output. |
| |
| ref: https://issues.apache.org/jira/browse/CASSANDRA-7159 and |
| https://issues.apache.org/jira/browse/CASSANDRA-10838 |
| |
| Cassandra must be stopped before this tool is executed, or unexpected |
| results will occur. Note: the script does not verify that Cassandra is |
| stopped. |
| |
| == Usage |
| |
| sstablemetadata <options> <sstable filename(s)> |
| |
| [cols=",",] |
| |=== |
| |--gc_grace_seconds <arg> |The gc_grace_seconds to use when calculating |
| droppable tombstones |
| |=== |
| |
| == Print all the metadata |
| |
| Run sstablemetadata against the __Data.db file(s) related to a table. If |
| necessary, find the__Data.db file(s) using sstableutil. |
| |
| Example: |
| |
| .... |
| sstableutil keyspace1 standard1 | grep Data |
| /var/lib/cassandra/data/keyspace1/standard1-f6845640a6cb11e8b6836d2c86545d91/mc-1-big-Data.db |
| |
| sstablemetadata /var/lib/cassandra/data/keyspace1/standard1-f6845640a6cb11e8b6836d2c86545d91/mc-1-big-Data.db |
| |
| SSTable: /var/lib/cassandra/data/keyspace1/standard1-f6845640a6cb11e8b6836d2c86545d91/mc-1-big |
| Partitioner: org.apache.cassandra.dht.Murmur3Partitioner |
| Bloom Filter FP chance: 0.010000 |
| Minimum timestamp: 1535025576141000 |
| Maximum timestamp: 1535025604309000 |
| SSTable min local deletion time: 2147483647 |
| SSTable max local deletion time: 2147483647 |
| Compressor: org.apache.cassandra.io.compress.LZ4Compressor |
| TTL min: 86400 |
| TTL max: 86400 |
| First token: -9223004712949498654 (key=39373333373831303130) |
| Last token: 9222554117157811897 (key=4f3438394e39374d3730) |
| Estimated droppable tombstones: 0.9188263888888889 |
| SSTable Level: 0 |
| Repaired at: 0 |
| Replay positions covered: {CommitLogPosition(segmentId=1535025390651, position=226400)=CommitLogPosition(segmentId=1535025390651, position=6849139)} |
| totalColumnsSet: 100000 |
| totalRows: 20000 |
| Estimated tombstone drop times: |
| 1535039100: 80390 |
| 1535039160: 5645 |
| 1535039220: 13965 |
| Count Row Size Cell Count |
| 1 0 0 |
| 2 0 0 |
| 3 0 0 |
| 4 0 0 |
| 5 0 20000 |
| 6 0 0 |
| 7 0 0 |
| 8 0 0 |
| 10 0 0 |
| 12 0 0 |
| 14 0 0 |
| 17 0 0 |
| 20 0 0 |
| 24 0 0 |
| 29 0 0 |
| 35 0 0 |
| 42 0 0 |
| 50 0 0 |
| 60 0 0 |
| 72 0 0 |
| 86 0 0 |
| 103 0 0 |
| 124 0 0 |
| 149 0 0 |
| 179 0 0 |
| 215 0 0 |
| 258 20000 0 |
| 310 0 0 |
| 372 0 0 |
| 446 0 0 |
| 535 0 0 |
| 642 0 0 |
| 770 0 0 |
| 924 0 0 |
| 1109 0 0 |
| 1331 0 0 |
| 1597 0 0 |
| 1916 0 0 |
| 2299 0 0 |
| 2759 0 0 |
| 3311 0 0 |
| 3973 0 0 |
| 4768 0 0 |
| 5722 0 0 |
| 6866 0 0 |
| 8239 0 0 |
| 9887 0 0 |
| 11864 0 0 |
| 14237 0 0 |
| 17084 0 0 |
| 20501 0 0 |
| 24601 0 0 |
| 29521 0 0 |
| 35425 0 0 |
| 42510 0 0 |
| 51012 0 0 |
| 61214 0 0 |
| 73457 0 0 |
| 88148 0 0 |
| 105778 0 0 |
| 126934 0 0 |
| 152321 0 0 |
| 182785 0 0 |
| 219342 0 0 |
| 263210 0 0 |
| 315852 0 0 |
| 379022 0 0 |
| 454826 0 0 |
| 545791 0 0 |
| 654949 0 0 |
| 785939 0 0 |
| 943127 0 0 |
| 1131752 0 0 |
| 1358102 0 0 |
| 1629722 0 0 |
| 1955666 0 0 |
| 2346799 0 0 |
| 2816159 0 0 |
| 3379391 0 0 |
| 4055269 0 0 |
| 4866323 0 0 |
| 5839588 0 0 |
| 7007506 0 0 |
| 8409007 0 0 |
| 10090808 0 0 |
| 12108970 0 0 |
| 14530764 0 0 |
| 17436917 0 0 |
| 20924300 0 0 |
| 25109160 0 0 |
| 30130992 0 0 |
| 36157190 0 0 |
| 43388628 0 0 |
| 52066354 0 0 |
| 62479625 0 0 |
| 74975550 0 0 |
| 89970660 0 0 |
| 107964792 0 0 |
| 129557750 0 0 |
| 155469300 0 0 |
| 186563160 0 0 |
| 223875792 0 0 |
| 268650950 0 0 |
| 322381140 0 0 |
| 386857368 0 0 |
| 464228842 0 0 |
| 557074610 0 0 |
| 668489532 0 0 |
| 802187438 0 0 |
| 962624926 0 0 |
| 1155149911 0 0 |
| 1386179893 0 0 |
| 1663415872 0 0 |
| 1996099046 0 0 |
| 2395318855 0 0 |
| 2874382626 0 |
| 3449259151 0 |
| 4139110981 0 |
| 4966933177 0 |
| 5960319812 0 |
| 7152383774 0 |
| 8582860529 0 |
| 10299432635 0 |
| 12359319162 0 |
| 14831182994 0 |
| 17797419593 0 |
| 21356903512 0 |
| 25628284214 0 |
| 30753941057 0 |
| 36904729268 0 |
| 44285675122 0 |
| 53142810146 0 |
| 63771372175 0 |
| 76525646610 0 |
| 91830775932 0 |
| 110196931118 0 |
| 132236317342 0 |
| 158683580810 0 |
| 190420296972 0 |
| 228504356366 0 |
| 274205227639 0 |
| 329046273167 0 |
| 394855527800 0 |
| 473826633360 0 |
| 568591960032 0 |
| 682310352038 0 |
| 818772422446 0 |
| 982526906935 0 |
| 1179032288322 0 |
| 1414838745986 0 |
| Estimated cardinality: 20196 |
| EncodingStats minTTL: 0 |
| EncodingStats minLocalDeletionTime: 1442880000 |
| EncodingStats minTimestamp: 1535025565275000 |
| KeyType: org.apache.cassandra.db.marshal.BytesType |
| ClusteringTypes: [org.apache.cassandra.db.marshal.UTF8Type] |
| StaticColumns: {C3:org.apache.cassandra.db.marshal.BytesType, C4:org.apache.cassandra.db.marshal.BytesType, C0:org.apache.cassandra.db.marshal.BytesType, C1:org.apache.cassandra.db.marshal.BytesType, C2:org.apache.cassandra.db.marshal.BytesType} |
| RegularColumns: {} |
| .... |
| |
| == Specify gc grace seconds |
| |
| To see the ratio of droppable tombstones given a configured gc grace |
| seconds, use the gc_grace_seconds option. Because the sstablemetadata |
| tool doesn't access the schema directly, this is a way to more |
| accurately estimate droppable tombstones -- for example, if you pass in |
| gc_grace_seconds matching what is configured in the schema. The |
| gc_grace_seconds value provided is subtracted from the curent machine |
| time (in seconds). |
| |
| ref: https://issues.apache.org/jira/browse/CASSANDRA-12208 |
| |
| Example: |
| |
| .... |
| sstablemetadata /var/lib/cassandra/data/keyspace1/standard1-41b52700b4ed11e896476d2c86545d91/mc-12-big-Data.db | grep "Estimated tombstone drop times" -A4 |
| Estimated tombstone drop times: |
| 1536599100: 1 |
| 1536599640: 1 |
| 1536599700: 2 |
| |
| echo $(date +%s) |
| 1536602005 |
| |
| # if gc_grace_seconds was configured at 100, all of the tombstones would be currently droppable |
| sstablemetadata --gc_grace_seconds 100 /var/lib/cassandra/data/keyspace1/standard1-41b52700b4ed11e896476d2c86545d91/mc-12-big-Data.db | grep "Estimated droppable tombstones" |
| Estimated droppable tombstones: 4.0E-5 |
| |
| # if gc_grace_seconds was configured at 4700, some of the tombstones would be currently droppable |
| sstablemetadata --gc_grace_seconds 4700 /var/lib/cassandra/data/keyspace1/standard1-41b52700b4ed11e896476d2c86545d91/mc-12-big-Data.db | grep "Estimated droppable tombstones" |
| Estimated droppable tombstones: 9.61111111111111E-6 |
| |
| # if gc_grace_seconds was configured at 100, none of the tombstones would be currently droppable |
| sstablemetadata --gc_grace_seconds 5000 /var/lib/cassandra/data/keyspace1/standard1-41b52700b4ed11e896476d2c86545d91/mc-12-big-Data.db | grep "Estimated droppable tombstones" |
| Estimated droppable tombstones: 0.0 |
| .... |
| |
| == Explanation of each value printed above |
| |
| |=== |
| |Value |Explanation |
| |
| |
| |SSTable |prefix of the sstable filenames related to this sstable |
| |Partitioner |partitioner type used to distribute data across nodes; |
| defined in cassandra.yaml |
| |Bloom Filter FP |precision of Bloom filter used |
| in reads; defined in the table definition |
| |Minimum timestamp |minimum |
| timestamp of any entry in this sstable, in epoch microseconds |
| |Maximum |
| timestamp |maximum timestamp of any entry in this sstable, in epoch |
| microseconds |
| |SSTable min local deletion time |minimum timestamp of |
| deletion date, based on TTL, in epoch seconds |
| |SSTable max local deletion |
| time |maximum timestamp of deletion date, based on TTL, in epoch seconds |
| |Compressor |blank (-) by default; if not blank, indicates type of |
| compression enabled on the table |
| |TTL min |time-to-live in seconds; |
| default 0 unless defined in the table definition |
| |TTL max |time-to-live in |
| seconds; default 0 unless defined in the table definition |
| |First token |lowest token and related key found in the sstable summary |
| |Last token |highest token and related key found in the sstable summary |
| |Estimated |
| droppable tombstones |ratio of tombstones to columns, using configured gc |
| grace seconds if relevant |
| |SSTable level |compaction level of this |
| sstable, if leveled compaction (LCS) is used |
| |Repaired at |the timestamp |
| this sstable was marked as repaired via sstablerepairedset, in epoch |
| milliseconds |
| |Replay positions covered |the interval of time and commitlog |
| positions related to this sstable |
| |totalColumnsSet |number of cells in the |
| table |
| |totalRows |number of rows in the table |
| |Estimated tombstone drop |
| times |approximate number of rows that will expire, ordered by epoch |
| seconds |
| |Count Row Size Cell Count |two histograms in two columns; one |
| represents distribution of Row Size and the other represents |
| distribution of Cell Count |
| |Estimated cardinality an estimate of unique |
| values, used for compaction |
| |EncodingStats* minTTL |in epoch milliseconds |
| |EncodingStats* minLocalDeletionTime |in epoch seconds |
| |EncodingStats* |
| minTimestamp |in epoch microseconds |
| |KeyType |the type of partition key, |
| useful in reading and writing data from/to storage; defined in the table |
| definition |
| |ClusteringTypes |the type of clustering key, useful in reading |
| and writing data from/to storage; defined in the table definition |
| |StaticColumns |a list of the shared columns in the table |
| |RegularColumns |a |
| list of non-static, non-key columns in the table |
| |=== |
| |
| `*` For the encoding stats values, the delta of this and the current epoch |
| time is used when encoding and storing data in the most optimal way. |
