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authorAmit Kapila <akapila@postgresql.org>2020-10-27 08:22:39 +0530
committerAmit Kapila <akapila@postgresql.org>2020-10-27 08:22:39 +0530
commit2f0760c9ff827bb3d23ee327e6b46038000c7ef9 (patch)
tree290dc24ef8fadb90f0d372696d4f298c2c76155e /doc/src
parent2f17fe431860fc434084d99d8b789e6ec7e6977b (diff)
downloadpostgresql-2f0760c9ff827bb3d23ee327e6b46038000c7ef9.tar.gz
postgresql-2f0760c9ff827bb3d23ee327e6b46038000c7ef9.zip
Update description of spilled counters in pg_stat_replication_slots view.
This is to make the description of spilled counters clear. Author: Amit Kapila Reviewed-by: Sawada Masahiko Discussion: https://postgr.es/m/CA+fd4k5_pPAYRTDrO2PbtTOe0eHQpBvuqmCr8ic39uTNmR49Eg@mail.gmail.com
Diffstat (limited to 'doc/src')
-rw-r--r--doc/src/sgml/monitoring.sgml14
1 files changed, 9 insertions, 5 deletions
diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index f5cf163c8c6..aeb694d4a86 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -2603,9 +2603,9 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
</para>
<para>
Number of transactions spilled to disk after the memory used by
- logical decoding exceeds <literal>logical_decoding_work_mem</literal>. The
- counter gets incremented both for toplevel transactions and
- subtransactions.
+ logical decoding of changes from WAL for this slot exceeds
+ <literal>logical_decoding_work_mem</literal>. The counter gets
+ incremented both for toplevel transactions and subtransactions.
</para></entry>
</row>
@@ -2614,7 +2614,8 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
<structfield>spill_count</structfield> <type>bigint</type>
</para>
<para>
- Number of times transactions were spilled to disk. Transactions
+ Number of times transactions were spilled to disk while performing
+ decoding of changes from WAL for this slot. Transactions
may get spilled repeatedly, and this counter gets incremented on every
such invocation.
</para></entry>
@@ -2625,7 +2626,10 @@ SELECT pid, wait_event_type, wait_event FROM pg_stat_activity WHERE wait_event i
<structfield>spill_bytes</structfield> <type>bigint</type>
</para>
<para>
- Amount of decoded transaction data spilled to disk.
+ Amount of decoded transaction data spilled to disk while performing
+ decoding of changes from WAL for this slot. This and other spill
+ counters can be used to gauge the I/O occurred during logical decoding
+ and accordingly can tune <literal>logical_decoding_work_mem</literal>.
</para></entry>
</row>