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https://issues.apache.org/jira/browse/CASSANDRA-18134?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jacek Lewandowski updated CASSANDRA-18134:
------------------------------------------
Description:
This patch improves the following things:
# SSTable metadata will store a covered slice in addition min/max clusterings.
The difference is that for slices there is available the type of a bound rather
than just a clustering. In particular it will provide the information whether
the lower and upper bound of an sstable is opened or closed. The legacy min/max
clustering will be stored until a new major format {{o}} to ensure backward
compatibility
# SSTable metadata will store a flag whether the SSTable contains any partition
level deletions or not
# SSTable metadata will store the first and the last keys of the sstable. This
is mostly for consistency - key range is logically a part of stats metadata. So
far it is stored at the end of the index summary. After this change, index
summary will be no longer needed to read key range of an sstable (although we
will keep storing key range as before for compatibility reasons)
# The above two changes required to introduce a new minor format for SSTables -
{{nc}}
# Single partition read command makes use of the above changes. In particular
an sstable can be skipped when it does not intersect with the column filter,
does not have partition level deletions and does not have statics; In case
there are partition level deletions, but the other conditions are satisfied,
only the partition header needs to be accessed (tests attached)
# Skipping sstables assuming those three conditions are satisfied has been
implemented also for partition range queries (tests attached). Also added minor
separate statistics to record the number of accessed sstables in partition
reads because now not all of them need to be accessed. That statistics is also
needed in tests to confirm skipping.
# Artificial lower bound marker is now an object on its own and is not
implemented as a special case of range tombstone bound. Instead it sorts right
before the lowest available bound in the data
# Extended the lower bound optimization usage due the 1 and 2
# Do not initialize iterator just to get a cached partition and associated
columns index. The purpose of using lower bound optimization was to avoid
opening an iterator of an sstable if possible.
See also CASSANDRA-14861
The changes in this patch include work of [~blambov], [~slebresne],
[~jakubzytka] and [~jlewandowski]
was:
This patch improves the following things:
# SSTable metadata will store a covered slice in addition min/max clusterings.
The difference is that for slices there is available the type of a bound rather
than just a clustering. In particular it will provide the information whether
the lower and upper bound of an sstable is opened or closed. The legacy min/max
clustering will be stored until a new major format {{o}} to ensure backward
compatibility
# SSTable metadata will store a flag whether the SSTable contains any partition
level deletions or not
# SSTable metadata will store the first and the last keys of the sstable. This
is mostly for consistency - key range is logically a part of stats metadata. So
far it is stored at the end of the index summary. After this change, index
summary will be no longer needed to read key range of an sstable (although we
will keep storing key range as before for compatibility reasons)
#
# The above two changes required to introduce a new minor format for SSTables -
{{nc}}
# Single partition read command makes use of the above changes. In particular
an sstable can be skipped when it does not intersect with the column filter,
does not have partition level deletions and does not have statics; In case
there are partition level deletions, but the other conditions are satisfied,
only the partition header needs to be accessed (tests attached)
# Skipping sstables assuming those three conditions are satisfied has been
implemented also for partition range queries (tests attached). Also added minor
separate statistics to record the number of accessed sstables in partition
reads because now not all of them need to be accessed. That statistics is also
needed in tests to confirm skipping.
# Artificial lower bound marker is now an object on its own and is not
implemented as a special case of range tombstone bound. Instead it sorts right
before the lowest available bound in the data
# Extended the lower bound optimization usage due the 1 and 2
# Do not initialize iterator just to get a cached partition and associated
columns index. The purpose of using lower bound optimization was to avoid
opening an iterator of an sstable if possible.
See also CASSANDRA-14861
The changes in this patch include work of [~blambov], [~slebresne],
[~jakubzytka] and [~jlewandowski]
> Improve handling of min/max clustering in sstable
> -------------------------------------------------
>
> Key: CASSANDRA-18134
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18134
> Project: Cassandra
> Issue Type: Improvement
> Components: Local/SSTable
> Reporter: Jacek Lewandowski
> Assignee: Jacek Lewandowski
> Priority: Normal
> Fix For: 5.x
>
>
> This patch improves the following things:
> # SSTable metadata will store a covered slice in addition min/max
> clusterings. The difference is that for slices there is available the type of
> a bound rather than just a clustering. In particular it will provide the
> information whether the lower and upper bound of an sstable is opened or
> closed. The legacy min/max clustering will be stored until a new major format
> {{o}} to ensure backward compatibility
> # SSTable metadata will store a flag whether the SSTable contains any
> partition level deletions or not
> # SSTable metadata will store the first and the last keys of the sstable.
> This is mostly for consistency - key range is logically a part of stats
> metadata. So far it is stored at the end of the index summary. After this
> change, index summary will be no longer needed to read key range of an
> sstable (although we will keep storing key range as before for compatibility
> reasons)
> # The above two changes required to introduce a new minor format for SSTables
> - {{nc}}
> # Single partition read command makes use of the above changes. In particular
> an sstable can be skipped when it does not intersect with the column filter,
> does not have partition level deletions and does not have statics; In case
> there are partition level deletions, but the other conditions are satisfied,
> only the partition header needs to be accessed (tests attached)
> # Skipping sstables assuming those three conditions are satisfied has been
> implemented also for partition range queries (tests attached). Also added
> minor separate statistics to record the number of accessed sstables in
> partition reads because now not all of them need to be accessed. That
> statistics is also needed in tests to confirm skipping.
> # Artificial lower bound marker is now an object on its own and is not
> implemented as a special case of range tombstone bound. Instead it sorts
> right before the lowest available bound in the data
> # Extended the lower bound optimization usage due the 1 and 2
> # Do not initialize iterator just to get a cached partition and associated
> columns index. The purpose of using lower bound optimization was to avoid
> opening an iterator of an sstable if possible.
> See also CASSANDRA-14861
> The changes in this patch include work of [~blambov], [~slebresne],
> [~jakubzytka] and [~jlewandowski]
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