DODB PDF.
parent
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commit
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.G1
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copy "legend.grap"
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frame invis ht 3 wid 4 left solid bot solid
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coord y 0,50
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ticks left out from 0 to 50 by 10
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ticks bot out at 50000 "50,000", 100000 "100,000", 150000 "150,000", 200000 "200,000", 250000 "250,000"
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label left "Request duration with" unaligned "an index (µs)" "(Median)" left 0.8
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label bot "Number of cars in the database" down 0.1
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obram = obuncache = obcache = obsemi = 0 # old bullets
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cbram = cbuncache = cbcache = cbsemi = 0 # current bullets
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legendxleft = 100000
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legendxright = 250000
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legendyup = 15
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legendydown = 2
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boite(legendxleft,legendxright,legendyup,legendydown)
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legend(legendxleft,legendxright,legendyup,legendydown)
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copy "../data/index.d" thru X
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cx = $1*5
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y_scale = 1000
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# ram cached semi uncached
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line from cx,$2/y_scale to cx,$4/y_scale
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line from cx,$5/y_scale to cx,$7/y_scale
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line from cx,$8/y_scale to cx,$10/y_scale
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line from cx,$11/y_scale to cx,$13/y_scale
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#ty = $3
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cx = $1*5
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cbram = $3/y_scale
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cbcache = $6/y_scale
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cbsemi = $9/y_scale
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cbuncache = $12/y_scale
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if (obram > 0) then {line from cx,cbram to ox,obram}
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if (obcache > 0) then {line from cx,cbcache to ox,obcache}
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.gcolor blue
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if (obsemi > 0) then {line from cx,cbsemi to ox,obsemi}
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.gcolor
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.gcolor green
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if (obuncache > 0) then {line from cx,cbuncache to ox,obuncache}
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.gcolor
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obram = cbram
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obcache = cbcache
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obsemi = cbsemi
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obuncache = cbuncache
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ox = cx
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# ram cached semi uncached
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.gcolor red
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bullet at cx,cbram
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.gcolor
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bullet at cx,cbcache
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.gcolor blue
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bullet at cx,cbsemi
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.gcolor
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.gcolor green
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bullet at cx,cbuncache
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.gcolor
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X
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.G2
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@ -0,0 +1,66 @@
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.G1
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copy "legend.grap"
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frame invis ht 3 wid 4 left solid bot solid
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coord x 0,5000*2 y 0,350
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ticks left out from 0 to 350 by 50
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label left "Request duration" unaligned "for a partition (ms)" "(Median)" left 0.8
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label bot "Number of cars matching the partition" down 0.1
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obram = obuncache = obcache = obsemi = 0
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cbram = cbuncache = cbcache = cbsemi = 0
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legendxleft = 1000
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legendxright = 6500
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legendyup = 330
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legendydown = 230
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boite(legendxleft,legendxright,legendyup,legendydown)
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legend(legendxleft,legendxright,legendyup,legendydown)
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copy "../data/partitions.d" thru X
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cx = $1*2
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y_scale = 1000000
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# ram cached semi uncached
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line from cx,$2/y_scale to cx,$4/y_scale
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line from cx,$5/y_scale to cx,$7/y_scale
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line from cx,$8/y_scale to cx,$10/y_scale
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line from cx,$11/y_scale to cx,$13/y_scale
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#ty = $3
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cbram = $3/y_scale
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cbcache = $6/y_scale
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cbsemi = $9/y_scale
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cbuncache = $12/y_scale
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if (obram > 0) then {line from cx,cbram to ox,obram}
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if (obcache > 0) then {line from cx,cbcache to ox,obcache}
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.gcolor blue
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if (obsemi > 0) then {line from cx,cbsemi to ox,obsemi}
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.gcolor
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.gcolor green
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if (obuncache > 0) then {line from cx,cbuncache to ox,obuncache}
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.gcolor
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obram = cbram
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obcache = cbcache
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obsemi = cbsemi
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obuncache = cbuncache
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ox = cx
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# ram cached semi uncached
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.gcolor red
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bullet at cx,cbram
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.gcolor
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bullet at cx,cbcache
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.gcolor blue
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bullet at cx,cbsemi
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.gcolor
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.gcolor green
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bullet at cx,cbuncache
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.gcolor
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X
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.G2
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@ -0,0 +1,65 @@
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.G1
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copy "legend.grap"
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frame invis ht 3 wid 4 left solid bot solid
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coord x 0,5000 y 0,170
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ticks left out from 0 to 170 by 20
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label left "Request duration" unaligned "for a tag (ms)" "(Median)" left 0.8
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label bot "Number of cars matching the tag" down 0.1
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obram = obuncache = obcache = obsemi = 0
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cbram = cbuncache = cbcache = cbsemi = 0
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legendxleft = 200
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legendxright = 3000
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legendyup = 170
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legendydown = 120
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boite(legendxleft,legendxright,legendyup,legendydown)
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legend(legendxleft,legendxright,legendyup,legendydown)
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copy "../data/tags.d" thru X
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cx = $1
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y_scale = 1000000
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# ram cached semi uncached
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line from cx,$2/y_scale to cx,$4/y_scale
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line from cx,$5/y_scale to cx,$7/y_scale
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line from cx,$8/y_scale to cx,$10/y_scale
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line from cx,$11/y_scale to cx,$13/y_scale
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#ty = $3
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cbram = $3/y_scale
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cbcache = $6/y_scale
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cbsemi = $9/y_scale
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cbuncache = $12/y_scale
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if (obram > 0) then {line from cx,cbram to ox,obram}
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if (obcache > 0) then {line from cx,cbcache to ox,obcache}
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.gcolor blue
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if (obsemi > 0) then {line from cx,cbsemi to ox,obsemi}
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.gcolor
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.gcolor green
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if (obuncache > 0) then {line from cx,cbuncache to ox,obuncache}
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.gcolor
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obram = cbram
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obcache = cbcache
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obsemi = cbsemi
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obuncache = cbuncache
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ox = cx
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# ram cached semi uncached
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.gcolor red
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bullet at cx,cbram
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.gcolor
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bullet at cx,cbcache
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.gcolor blue
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bullet at cx,cbsemi
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.gcolor
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.gcolor green
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bullet at cx,cbuncache
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.gcolor
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X
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.G2
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272
graphs/graphs.ms
272
graphs/graphs.ms
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@ -1,5 +1,5 @@
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.so macros.roff
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.TITLE Brief performance analysis of Document Oriented DataBase (DODB)
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.TITLE Document Oriented DataBase (DODB)
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.AUTHOR Philippe P.
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.ABSTRACT1
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DODB is a database-as-library, enabling a very simple way to store applications' data: storing serialized
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@ -9,10 +9,46 @@ To speed-up searches, attributes of these documents can be used as indexes which
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.I symlinks ) (
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on the disk.
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.br
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See the \f[CW]README\f[] for a longer explanation.
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This document briefly presents an experiment to understand the performances we can get with this approach.
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This document briefly presents DODB and its main differences with other database engines.
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An experiment is described and analysed to understand the performance that can be expected from this approach.
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.ABSTRACT2
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.SECTION Introduction to DODB
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A database consists in managing data, enabling queries (preferably fast) to retrieve, to modify, to add and to delete a piece of information.
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Anything else is
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.UL accessory .
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Universities all around the world teach about Structured Query Language (SQL) and relational databases.
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The main idea of relational databases is to put data into
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.I tables ,
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with typed columns so the database can optimize operations and storage.
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A database is a list of tables with relations between them.
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For example, let's imagine a database of a
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.I table
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can contain a list of users (their age, height, job, etc.).
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When another
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The SQL language enables arbitrary operations on databases: add, modify and delete entries.
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Furthermore, SQL enables even to manage administrative operations of the databases themselves: managing users with fine-grained authorizations, creating databases and tables, etc.
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Many tools were used or even developed over the years specifically to aleviate the inherent complexity and limitations of SQL.
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For example, Unified Modeling Language (UML) is used to design databases by providing a graphical overview of the relations between tables.
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SQL databases can be scripted to automate operations and provide a massive speed up to the operations (
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.I "stored procedures" ,
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see
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.I "PL/SQL" ),
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etc.
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Document-oriented databases are key-value stores.
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Furthermore, metadata is extracted for further optimization.
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Contrary to SQL, DODB has a very narrow scope: to provide
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Thus, DODB doesn't provide an interactive shell, no request language to perform arbitrary operations on the database, etc.
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.SECTION Basic usage
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.SECTION A few more options
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.SECTION Limits of DODB
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.SECTION Experimental scenario
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.LP
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The following experiment shows the performance of DODB based on quering durations.
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@ -61,7 +97,7 @@ class Car
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end
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.SOURCE
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.
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.SECTION Basic indexes (1 to 1 relations)
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.SS Basic indexes (1 to 1 relations)
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.LP
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An index enables to match a single value based on a small string.
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In our example, each \f[CW]car\f[] has an unique \fIname\f[] which is used as an index.
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@ -69,213 +105,43 @@ In our example, each \f[CW]car\f[] has an unique \fIname\f[] which is used as an
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The following graph represents the result of 100 queries of a car based on its name.
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The experiment starts with a database containing 1,000 cars and goes up to 250,000 cars.
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.so graph_query_index.grap
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Since there is only one value to retrieve, the request is quick and time is almost constant.
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When the value and the index are kept in memory (see \f[CW]RAM only\f[] and \f[CW]Cached db\f[]), the retrieval is almost instantaneous (about 50 to 120 ns).
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In case the value is on the disk, deserialization takes about 15 µs (see \f[CW]Uncached db, cached index\f[]).
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The request is a little longer when the index isn't cached, in this case DODB walks the file-system to find the right symlink to follow, thus slowing the process even more, by up to 20%.
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.G1
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copy "legend.grap"
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frame invis ht 3 wid 4 left solid bot solid
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coord y 0,50
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ticks left out from 0 to 50 by 10
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ticks bot out at 50000 "50,000", 100000 "100,000", 150000 "150,000", 200000 "200,000", 250000 "250,000"
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The request is a little longer when the index isn't cached (see \f[CW]Uncached db and index\f[]); in this case DODB walks the file-system to find the right symlink to follow, thus slowing the process even more, by up to 20%.
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label left "Request duration with" unaligned "an index (us)" "(Median)" left 0.8
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label bot "Number of cars in the database" down 0.1
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.TS
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allbox tab(:);
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c | lw(4.0i) | cew(1.4i).
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DODB instance:Comment and database usage:T{
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compared to RAM only
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T}
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RAM only:T{
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Worst memory footprint (all data must be in memory), best performance.
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T}:-
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Cached db and index:T{
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Performance for retrieving a value is the same as RAM only while
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enabling the admin to manually search for data on-disk.
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T}:about the same perfs
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Uncached db, cached index::300 to 400x slower
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Uncached db and index:T{
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Best memory footprint, worst performance.
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T}:400 to 500x slower
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.TE
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obram = obuncache = obcache = obsemi = 0 # old bullets
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cbram = cbuncache = cbcache = cbsemi = 0 # current bullets
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legendxleft = 100000
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legendxright = 250000
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legendyup = 15
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legendydown = 2
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boite(legendxleft,legendxright,legendyup,legendydown)
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legend(legendxleft,legendxright,legendyup,legendydown)
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copy "../data/index.d" thru X
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cx = $1*5
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y_scale = 1000
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# ram cached semi uncached
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line from cx,$2/y_scale to cx,$4/y_scale
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line from cx,$5/y_scale to cx,$7/y_scale
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line from cx,$8/y_scale to cx,$10/y_scale
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line from cx,$11/y_scale to cx,$13/y_scale
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#ty = $3
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cx = $1*5
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cbram = $3/y_scale
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cbcache = $6/y_scale
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cbsemi = $9/y_scale
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cbuncache = $12/y_scale
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if (obram > 0) then {line from cx,cbram to ox,obram}
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if (obcache > 0) then {line from cx,cbcache to ox,obcache}
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.gcolor blue
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if (obsemi > 0) then {line from cx,cbsemi to ox,obsemi}
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.gcolor
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.gcolor green
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if (obuncache > 0) then {line from cx,cbuncache to ox,obuncache}
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.gcolor
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obram = cbram
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obcache = cbcache
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obsemi = cbsemi
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obuncache = cbuncache
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ox = cx
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# ram cached semi uncached
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.gcolor red
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bullet at cx,cbram
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.gcolor
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bullet at cx,cbcache
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.gcolor blue
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bullet at cx,cbsemi
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.gcolor
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.gcolor green
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bullet at cx,cbuncache
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.gcolor
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X
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.G2
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.B Conclusion :
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as expected, retrieving a single value is fast and the size of the database doesn't matter much.
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Each deserialization and, more importantly, each disk access is a pain point.
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Caching the value enables a massive performance gain, data can be retrieved several hundred times quicker.
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.bp
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.SECTION Partitions (1 to n relations)
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.SS Partitions (1 to n relations)
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.LP
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.G1
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copy "legend.grap"
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frame invis ht 3 wid 4 left solid bot solid
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coord x 0,5000*2 y 0,350
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ticks left out from 0 to 350 by 50
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label left "Request duration" unaligned "for a partition (ms)" "(Median)" left 0.8
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label bot "Number of cars matching the partition" down 0.1
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.so graph_query_partition.grap
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obram = obuncache = obcache = obsemi = 0
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cbram = cbuncache = cbcache = cbsemi = 0
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legendxleft = 1000
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legendxright = 6500
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legendyup = 330
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legendydown = 230
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boite(legendxleft,legendxright,legendyup,legendydown)
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legend(legendxleft,legendxright,legendyup,legendydown)
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copy "../data/partitions.d" thru X
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cx = $1*2
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y_scale = 1000000
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# ram cached semi uncached
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line from cx,$2/y_scale to cx,$4/y_scale
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line from cx,$5/y_scale to cx,$7/y_scale
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line from cx,$8/y_scale to cx,$10/y_scale
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line from cx,$11/y_scale to cx,$13/y_scale
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#ty = $3
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cbram = $3/y_scale
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cbcache = $6/y_scale
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cbsemi = $9/y_scale
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cbuncache = $12/y_scale
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if (obram > 0) then {line from cx,cbram to ox,obram}
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if (obcache > 0) then {line from cx,cbcache to ox,obcache}
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.gcolor blue
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if (obsemi > 0) then {line from cx,cbsemi to ox,obsemi}
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.gcolor
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.gcolor green
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if (obuncache > 0) then {line from cx,cbuncache to ox,obuncache}
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.gcolor
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obram = cbram
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obcache = cbcache
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obsemi = cbsemi
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obuncache = cbuncache
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ox = cx
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# ram cached semi uncached
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.gcolor red
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bullet at cx,cbram
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.gcolor
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bullet at cx,cbcache
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.gcolor blue
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bullet at cx,cbsemi
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.gcolor
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.gcolor green
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bullet at cx,cbuncache
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.gcolor
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X
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.G2
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.bp
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.SECTION Tags (n to n relations)
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.SS Tags (n to n relations)
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.LP
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.G1
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copy "legend.grap"
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frame invis ht 3 wid 4 left solid bot solid
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coord x 0,5000 y 0,170
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ticks left out from 0 to 170 by 20
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label left "Request duration" unaligned "for a tag (ms)" "(Median)" left 0.8
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label bot "Number of cars matching the tag" down 0.1
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obram = obuncache = obcache = obsemi = 0
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cbram = cbuncache = cbcache = cbsemi = 0
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legendxleft = 200
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legendxright = 3000
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legendyup = 170
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legendydown = 120
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boite(legendxleft,legendxright,legendyup,legendydown)
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||||
legend(legendxleft,legendxright,legendyup,legendydown)
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copy "../data/tags.d" thru X
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cx = $1
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y_scale = 1000000
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# ram cached semi uncached
|
||||
line from cx,$2/y_scale to cx,$4/y_scale
|
||||
line from cx,$5/y_scale to cx,$7/y_scale
|
||||
line from cx,$8/y_scale to cx,$10/y_scale
|
||||
line from cx,$11/y_scale to cx,$13/y_scale
|
||||
|
||||
#ty = $3
|
||||
|
||||
cbram = $3/y_scale
|
||||
cbcache = $6/y_scale
|
||||
cbsemi = $9/y_scale
|
||||
cbuncache = $12/y_scale
|
||||
|
||||
if (obram > 0) then {line from cx,cbram to ox,obram}
|
||||
if (obcache > 0) then {line from cx,cbcache to ox,obcache}
|
||||
.gcolor blue
|
||||
if (obsemi > 0) then {line from cx,cbsemi to ox,obsemi}
|
||||
.gcolor
|
||||
.gcolor green
|
||||
if (obuncache > 0) then {line from cx,cbuncache to ox,obuncache}
|
||||
.gcolor
|
||||
|
||||
obram = cbram
|
||||
obcache = cbcache
|
||||
obsemi = cbsemi
|
||||
obuncache = cbuncache
|
||||
ox = cx
|
||||
|
||||
# ram cached semi uncached
|
||||
.gcolor red
|
||||
bullet at cx,cbram
|
||||
.gcolor
|
||||
bullet at cx,cbcache
|
||||
.gcolor blue
|
||||
bullet at cx,cbsemi
|
||||
.gcolor
|
||||
.gcolor green
|
||||
bullet at cx,cbuncache
|
||||
.gcolor
|
||||
X
|
||||
.G2
|
||||
.so graph_query_tag.grap
|
||||
|
|
|
|||
|
|
@ -20,7 +20,7 @@ define legend {
|
|||
diffy = yup - ydown
|
||||
|
||||
hdiff = diffy/4.3
|
||||
cy = yup - (diffy/8)
|
||||
cy = yup - (diffy/6)
|
||||
cx = (diffx/20) + xleft
|
||||
|
||||
lstartx = cx
|
||||
|
|
@ -33,7 +33,7 @@ define legend {
|
|||
"RAM only" ljust at tstartx,cy
|
||||
cy = cy - hdiff
|
||||
line from lstartx,cy to lendx,cy
|
||||
"Cached DODB" ljust at tstartx,cy
|
||||
"Cached db and index" ljust at tstartx,cy
|
||||
cy = cy - hdiff
|
||||
.gcolor blue
|
||||
line from lstartx,cy to lendx,cy
|
||||
|
|
|
|||
Loading…
Reference in New Issue