add frozen memtable figure

Signed-off-by: Alex Chi <iskyzh@gmail.com>

mini-lsm-book/src/lsm-tutorial/00-full-overview.svg

@@ -1,6 +1,6 @@
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 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
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+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="-5 170 704 599" width="704" height="599">
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@@ -8,7 +8,7 @@
       </g>
     </marker>
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-  <g id="00-full-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="00-full-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>00-full-overview</title>
     <rect fill="white" x="-5" y="170" width="704" height="599"/>
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mini-lsm-book/src/lsm-tutorial/00-lsm-read-flow.svg

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
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+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 194 693 361" width="693" height="361">
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       <g>
@@ -18,7 +18,7 @@
       </g>
     </marker>
   </defs>
-  <g id="00-lsm-read-flow" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="00-lsm-read-flow" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>00-lsm-read-flow</title>
     <rect fill="white" x="6" y="194" width="693" height="361"/>
     <g id="00-lsm-read-flow_Layer_1">

mini-lsm-book/src/lsm-tutorial/00-lsm-write-flow.svg

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
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+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 245 693 273" width="693" height="273">
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       <g>
@@ -13,7 +13,7 @@
       </g>
     </marker>
   </defs>
-  <g id="00-lsm-write-flow" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="00-lsm-write-flow" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>00-lsm-write-flow</title>
     <rect fill="white" x="6" y="245" width="693" height="273"/>
     <g id="00-lsm-write-flow_Layer_1">

mini-lsm-book/src/lsm-tutorial/week1-01-frozen.svg

@@ -0,0 +1,70 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 214 693 135" width="693" height="135">
+  <defs>
+    <marker orient="auto" overflow="visible" markerUnits="strokeWidth" id="FilledArrow_Marker" stroke-linejoin="miter" stroke-miterlimit="10" viewBox="-1 -4 10 8" markerWidth="10" markerHeight="8" color="black">
+      <g>
+        <path d="M 8 0 L 0 -3 L 0 3 Z" fill="currentColor" stroke="currentColor" stroke-width="1"/>
+      </g>
+    </marker>
+    <marker orient="auto" overflow="visible" markerUnits="strokeWidth" id="FilledArrow_Marker_2" stroke-linejoin="miter" stroke-miterlimit="10" viewBox="-9 -4 10 8" markerWidth="10" markerHeight="8" color="#7f8080">
+      <g>
+        <path d="M -8 0 L 0 3 L 0 -3 Z" fill="currentColor" stroke="currentColor" stroke-width="1"/>
+      </g>
+    </marker>
+  </defs>
+  <g id="week1-01-frozen" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
+    <title>week1-01-frozen</title>
+    <rect fill="white" x="6" y="214" width="693" height="135"/>
+    <g id="week1-01-frozen_Layer_1">
+      <title>Layer 1</title>
+      <g id="Line_37">
+        <line x1="7" y1="319" x2="697.696" y2="319" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-dasharray="4.0,4.0" stroke-width="1"/>
+      </g>
+      <g id="Graphic_36">
+        <text transform="translate(12 325)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="0" y="15">On Disk</tspan>
+        </text>
+      </g>
+      <g id="Graphic_35">
+        <text transform="translate(12 296.552)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="0" y="15">In Memory</tspan>
+        </text>
+      </g>
+      <g id="Graphic_32">
+        <rect x="273.68968" y="245.974" width="73.31032" height="41.5" fill="white"/>
+        <rect x="273.68968" y="245.974" width="73.31032" height="41.5" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+        <text transform="translate(278.68968 257.5)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="4.983159" y="15">Current</tspan>
+        </text>
+      </g>
+      <g id="Graphic_30">
+        <rect x="500.31726" y="252.052" width="124.08348" height="28.447998" fill="white"/>
+        <rect x="500.31726" y="252.052" width="124.08348" height="28.447998" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+        <text transform="translate(505.31726 257.052)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="16.52974" y="15">key + value</tspan>
+        </text>
+      </g>
+      <g id="Line_27">
+        <line x1="500.31726" y1="266.3863" x2="356.9" y2="266.64124" marker-end="url(#FilledArrow_Marker)" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+      </g>
+      <g id="Graphic_38">
+        <rect x="195" y="245.974" width="62.81032" height="41.5" fill="white"/>
+        <rect x="195" y="245.974" width="62.81032" height="41.5" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+        <text transform="translate(200 257.5)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="2.117159" y="15">Frozen</tspan>
+        </text>
+      </g>
+      <g id="Line_39">
+        <path d="M 240.73783 237.3985 C 248.2207 225.4971 258.08746 214.5 269 214.5 C 282.52838 214.5 294.045 231.40123 301.4606 245.974" marker-start="url(#FilledArrow_Marker_2)" stroke="#7f8080" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+      </g>
+      <g id="Graphic_40">
+        <rect x="116.31032" y="245.974" width="62.81032" height="41.5" fill="white"/>
+        <rect x="116.31032" y="245.974" width="62.81032" height="41.5" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+        <text transform="translate(121.31032 257.5)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="2.117159" y="15">Frozen</tspan>
+        </text>
+      </g>
+    </g>
+  </g>
+</svg>

mini-lsm-book/src/lsm-tutorial/week1-01-overview.svg

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
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+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 213 693 136" width="693" height="136">
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@@ -8,7 +8,7 @@
       </g>
     </marker>
   </defs>
-  <g id="week1-01-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week1-01-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week1-01-overview</title>
     <rect fill="white" x="6" y="213" width="693" height="136"/>
     <g id="week1-01-overview_Layer_1">

mini-lsm-book/src/lsm-tutorial/week1-01-single.svg

@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 245 693 104" width="693" height="104">
+  <defs>
+    <marker orient="auto" overflow="visible" markerUnits="strokeWidth" id="FilledArrow_Marker" stroke-linejoin="miter" stroke-miterlimit="10" viewBox="-1 -4 10 8" markerWidth="10" markerHeight="8" color="black">
+      <g>
+        <path d="M 8 0 L 0 -3 L 0 3 Z" fill="currentColor" stroke="currentColor" stroke-width="1"/>
+      </g>
+    </marker>
+  </defs>
+  <g id="week1-01-single" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
+    <title>week1-01-single</title>
+    <rect fill="white" x="6" y="245" width="693" height="104"/>
+    <g id="week1-01-single_Layer_1">
+      <title>Layer 1</title>
+      <g id="Line_37">
+        <line x1="7" y1="319" x2="697.696" y2="319" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-dasharray="4.0,4.0" stroke-width="1"/>
+      </g>
+      <g id="Graphic_36">
+        <text transform="translate(12 325)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="0" y="15">On Disk</tspan>
+        </text>
+      </g>
+      <g id="Graphic_35">
+        <text transform="translate(12 296.552)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="0" y="15">In Memory</tspan>
+        </text>
+      </g>
+      <g id="Graphic_32">
+        <rect x="273.68968" y="245.974" width="62.81032" height="41.5" fill="white"/>
+        <rect x="273.68968" y="245.974" width="62.81032" height="41.5" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+        <text transform="translate(278.68968 248.276)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="8.317159" y="15">Mem </tspan>
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="7.589159" y="33.448">Table</tspan>
+        </text>
+      </g>
+      <g id="Graphic_30">
+        <rect x="500.31726" y="252.052" width="124.08348" height="28.447998" fill="white"/>
+        <rect x="500.31726" y="252.052" width="124.08348" height="28.447998" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+        <text transform="translate(505.31726 257.052)" fill="black">
+          <tspan font-family="Helvetica Neue" font-size="16" fill="black" x="16.52974" y="15">key + value</tspan>
+        </text>
+      </g>
+      <g id="Line_27">
+        <line x1="500.31726" y1="266.38404" x2="346.4" y2="266.65207" marker-end="url(#FilledArrow_Marker)" stroke="black" stroke-linecap="round" stroke-linejoin="round" stroke-width="1"/>
+      </g>
+    </g>
+  </g>
+</svg>

mini-lsm-book/src/lsm-tutorial/week1-02-overview.svg

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
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+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 213 693 136" width="693" height="136">
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@@ -8,7 +8,7 @@
       </g>
     </marker>
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-  <g id="week1-02-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week1-02-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week1-02-overview</title>
     <rect fill="white" x="6" y="213" width="693" height="136"/>
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mini-lsm-book/src/lsm-tutorial/week1-03-overview.svg

@@ -1,6 +1,6 @@
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@@ -8,7 +8,7 @@
       </g>
     </marker>
   </defs>
-  <g id="week1-03-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week1-03-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week1-03-overview</title>
     <rect fill="white" x="-5" y="245" width="704" height="524"/>
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mini-lsm-book/src/lsm-tutorial/week1-04-overview.svg

@@ -1,6 +1,6 @@
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+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 245 693 480" width="693" height="480">
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       </g>
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-  <g id="week1-04-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week1-04-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
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mini-lsm-book/src/lsm-tutorial/week1-05-overview.svg

@@ -1,6 +1,6 @@
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mini-lsm-book/src/lsm-tutorial/week1-07-overview.svg

@@ -1,6 +1,6 @@
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@@ -8,7 +8,7 @@
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-  <g id="week1-07-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week1-07-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week1-07-overview</title>
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mini-lsm-book/src/lsm-tutorial/week1-overview.svg

@@ -1,6 +1,6 @@
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-  <g id="week1-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week1-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week1-overview</title>
     <rect fill="white" x="-5" y="170" width="784" height="599"/>
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mini-lsm-book/src/lsm-tutorial/week2-01-overview.svg

@@ -1,6 +1,6 @@
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 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
-<svg xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xl="http://www.w3.org/1999/xlink" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 245 693 269" width="693" height="269">
+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 245 693 269" width="693" height="269">
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       <g>
@@ -8,7 +8,7 @@
       </g>
     </marker>
   </defs>
-  <g id="week2-01-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week2-01-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week2-01-overview</title>
     <rect fill="white" x="6" y="245" width="693" height="269"/>
     <g id="week2-01-overview_Layer_1">

mini-lsm-book/src/lsm-tutorial/week2-05-overview.svg

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
-<svg xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xl="http://www.w3.org/1999/xlink" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 245 765 268" width="765" height="268">
+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 245 765 268" width="765" height="268">
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       <g>
@@ -13,7 +13,7 @@
       </g>
     </marker>
   </defs>
-  <g id="week2-05-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week2-05-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week2-05-overview</title>
     <rect fill="white" x="6" y="245" width="765" height="268"/>
     <g id="week2-05-overview_Layer_1">

mini-lsm-book/src/lsm-tutorial/week2-06-overview.svg

@@ -1,6 +1,6 @@
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 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
-<svg xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xl="http://www.w3.org/1999/xlink" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 213 693 291" width="693" height="291">
+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 213 693 291" width="693" height="291">
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       <g>
@@ -8,7 +8,7 @@
       </g>
     </marker>
   </defs>
-  <g id="week2-06-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week2-06-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week2-06-overview</title>
     <rect fill="white" x="6" y="213" width="693" height="291"/>
     <g id="week2-06-overview_Layer_1">

mini-lsm-book/src/lsm-tutorial/week2-overview.svg

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
-<svg xmlns="http://www.w3.org/2000/svg" version="1.1" xmlns:xl="http://www.w3.org/1999/xlink" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 156 788 358" width="788" height="358">
+<svg xmlns:xl="http://www.w3.org/1999/xlink" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:dc="http://purl.org/dc/elements/1.1/" viewBox="6 156 788 358" width="788" height="358">
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       <g>
@@ -13,7 +13,7 @@
       </g>
     </marker>
   </defs>
-  <g id="week2-overview" fill-opacity="1" stroke-dasharray="none" fill="none" stroke-opacity="1" stroke="none">
+  <g id="week2-overview" stroke-dasharray="none" fill="none" fill-opacity="1" stroke="none" stroke-opacity="1">
     <title>week2-overview</title>
     <rect fill="white" x="6" y="156" width="788" height="358"/>
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mini-lsm-book/src/week1-01-memtable.md

@@ -37,7 +37,9 @@ Now, we will add our first data structure, the memtable, to the LSM state. In `L
 
 Taking a look at `lsm_storage.rs`, you will find there are two structures that represents a storage engine: `MiniLSM` and `LsmStorageInner`. `MiniLSM` is a thin wrapper for `LsmStorageInner`. You will implement most of the functionalities in `LsmStorageInner`, until week 2 compaction.
 
-`LsmStorageState` stores the current structure of the LSM storage engine. For now, we will only use the `memtable` field, which stores the current memtable. In this task, you will need to implement `LsmStorageInner::get`, `LsmStorageInner::put`, and `LsmStorageInner::delete`. All of them should directly dispatch the request to the current memtable.
+`LsmStorageState` stores the current structure of the LSM storage engine. For now, we will only use the `memtable` field, which stores the current mutable memtable. In this task, you will need to implement `LsmStorageInner::get`, `LsmStorageInner::put`, and `LsmStorageInner::delete`. All of them should directly dispatch the request to the current memtable.
+
+![one memtable LSM](./lsm-tutorial/week1-01-single.svg)
 
 Your `delete` implementation should simply put an empty slice for that key, and we call it a *delete tombstone*. Your `get` implementation should handle this case correspondingly.
 
@@ -52,6 +54,8 @@ src/lsm_storage.rs
 src/mem_table.rs
 ```
 
+![one memtable LSM](./lsm-tutorial/week1-01-frozen.svg)
+
 A memtable cannot continuously grow in size, and we will need to freeze them (and later flush to the disk) when it reaches the size limit. You may find the memtable size limit, which is equal to the SST size limit, in the `LsmStorageOptions`. This is not a hard limit and you should freeze the memtable at best effort.
 
 In this task, you will need to compute the approximate memtable size when put/delete a key in the memtable. This can be computed by simply adding the total number of bytes of keys and values when `put` is called. Is a key is put twice, though the skiplist only contains the latest value, you may count it twice in the approximate memtable size. Once a memtable reaches the limit, you should call `force_freeze_memtable` to freeze the memtable and create a new one.