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Posted to common-commits@hadoop.apache.org by Apache Wiki <wi...@apache.org> on 2007/04/17 17:30:17 UTC
[Lucene-hadoop Wiki] Trivial Update of "Hbase/HbaseArchitecture" by stack
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The following page has been changed by stack:
http://wiki.apache.org/lucene-hadoop/Hbase/HbaseArchitecture
The comment on the change is:
Sync doc w/ code: Add 'family name' delimiter to all column names, etc.
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may not have a value for a particular row key (sparse). The following example is a slightly modified form of the one on page 2 of the [http://labs.google.com/papers/bigtable.html Bigtable Paper].
[[Anchor(datamodelexample)]]
- ||<:> '''Row Key''' ||<:> '''Time Stamp''' ||<:> '''Column''' ''"contents:"'' ||||<:> '''Column''' ''"anchor:"'' ||<:> '''Column''' ''"mime"'' ||
+ ||<:> '''Row Key''' ||<:> '''Time Stamp''' ||<:> '''Column''' ''"contents:"'' ||||<:> '''Column''' ''"anchor:"'' ||<:> '''Column''' ''"mime:"'' ||
||<^|5> "com.cnn.www" ||<:> t9 || ||<)> "anchor:cnnsi.com" ||<:> "CNN" || ||
||<:> t8 || ||<)> "anchor:my.look.ca" ||<:> "CNN.com" || ||
||<:> t6 ||<:> "<html>..." || || ||<:> "text/html" ||
@@ -105, +105 @@
It is important to note in the diagram above that the empty cells
shown in the conceptual view are not stored. Thus a request for the
- value of the ''"contents"'' column at time stamp ''t8'' would return
+ value of the ''"contents:"'' column at time stamp ''t8'' would return
- a null value. Similarly, a request for an ''"anchor"'' value at time
+ a null value. Similarly, a request for an ''"anchor:"'' value at time
stamp ''t9'' for "my.look.ca" would return a null value.
However, if no timestamp is supplied, the most recent value for a
particular column would be returned and would also be the first one
found since time stamps are stored in descending order. Consequently
- the value returned for ''"contents"'' if no time stamp is supplied is
+ the value returned for ''"contents:"'' if no time stamp is supplied is
- the value for ''t6'' and the value for an ''"anchor"'' for
+ the value for ''t6'' and the value for an ''"anchor:"'' for
"my.look.ca" if no time stamp is supplied is the value for time stamp
''t8''.
=== Example ===
- To show how data is stored on disk, consider the folloing example:
+ To show how data is stored on disk, consider the following example:
A program writes rows "row[0-9]", column "anchor:foo"; then writes
rows "row[0-9]"; column "anchor:bar"; and finally writes rows
@@ -299, +299 @@
tablename + endkey + regionId.
- You can see this identifier being constructed in
+ (You can see this identifier being constructed in the
- HRegion.buildRegionName().
+ HRegionInfo constructor.)
[[Anchor(metadata)]]
= META Table =